No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Oceanic transport of fossil dammar resin: The chemistry of coastal resinites from South Australia
Abstract
Fragments of resin and fossilised resin (resinites) occasionally wash ashore along the southern Australian coast. Chemical and isotopic analyses were carried out on a suite of coastal and reference resinites to determine the likelihood of a local, as opposed to a distant, origin. All of the coastal resinites were found to contain a polymer based on the sesquiterpenoid cadinene skeleton and were markedly different to the diterpenoid resinites found in local Victorian coals. The coastal resinites closely resemble both fossil and recent dammar resin—a material associated primarily with the tropical angiosperm hardwoods of Southeast Asia, and one which has no known Australian source. Minor variations in the composition of our resinite samples are attributed to differences in their thermal history. These findings confirm the viability of long-distance oceanic transport, not only for the resinites but also for the waxy bitumens that strand along the same coastline.Analytical data on the coastal resinites also help to clarify the role of dammar resin in generating bicadinanes—a class of source and age-specific triterpanes found commonly in the Cainozoic oils and sediments of Southeast Asia.
... Later, the contribution of dipterocarp resins to oil formation was further shown by Murray et al (1994a) in a broader study in IAA localities, and by Stout (1995) focusing on sites in the Mahakam Delta in Kalimantan (Indonesian part of Borneo). At the same time, the first stable isotope analyses from dipterocarp ambers were conducted by Murray et al. (1994b), together with a detailed description of the organic chemistry of a Brunei specimen. This was followed by other works, including δ 13 C compositions of both modern and fossil resins from Borneo, undertaken by Stout (1995) and Murray et al. (1998). ...
... Consequently, these fossil samples are suggested to have drifted to Australia via oceanic currents from Southeast Asia. Interestingly, ambers of dipterocarp origin were also found on the beach in southern Australia, much farther away from an IAA source, and an oceanic transport from Southeast Asia was proposed here as well (Murray et al., 1994b). However, Coward et al. (2018) reported some undoubted autochthonous Eocene resins from southern Australia that belong to Class II resin suggesting a locally available polycadinene producing botanical source, which requires further investigations. ...
... In our study, the overall average carbon stable isotope compositions were found to be different for resins and ambers. Extending our database with data found in the literature (Murray et al., 1994b(Murray et al., , 1998Stout, 1995), the fossil samples show a more than 3 ‰ higher average value when compared to the modern ones (Fig. 10a). ...
In this study we intend to provide an overview on fossilized tree resins (amber) commonly found in Southeast Asia, more particularly in the Indo-Australian Archipelago (IAA). These remains are often referred in literature as “Indonesian amber”, “Borneo amber” or simply as “dammar”. They are very common in the region and the Brunei Sultanate is no exception as most of its Neogene sedimentary successions contain amber-rich layers. Although amber is a common fossil in the country and in northern Borneo, to our knowledge it has not been studied in great detail so far. Here we present an account on the “Borneo Ambers” from Brunei, regarding their stratigraphic origin, basic physical properties, their interaction with the biosphere and their botanical origin using Fourier-transform infrared spectroscopy (FTIR). Additionally, a number of ambers and modern tree resins were analysed for their carbon isotope composition and a few were tested with gas chromatography. We discuss the results in a regional and global context, in comparison with available data from the IAA.
The ambers come from four different lithostratigraphic units with an age range of 12 to 3 million years (middle Miocene to Pliocene). Recently reworked ambers from the coast, ambers from younger alluvial deposits, and several modern tree resins from Dipterocarpaceae and Araucariaceae (Agathis borneensis) were also included in the study. The >60 FTIR analyses of modern and fossil specimens suggest that all the Brunei ambers were produced by trees of Dipterocarpaceae. There is no indication of Agathis in the fossil record, in agreement with their lower abundance in the forests of Borneo. Modern and fossil dipterocarp resins were found to be different based on the following criteria: (1) Different reactions to solubility, hot needle and UV tests with faster reaction time and less fluorescence for the modern ones; (2) Clear distinction based on certain FTIR absorbance band ratios, mostly by those that represent carboxylic acids and esters (e.g., ~1700 and 1243 cm⁻¹); (3) Modern resin yielded on an average 3‰ lower δ¹³C values, (4) Gas chromatography data reflect maturation differences among the samples. Although there is some overlap in the chemical results between the two groups, generally all these differences reflect different maturation stages of the resinous material and point towards loss of low δ¹³C components from the organic structure of the resin. The minor timewise decreasing trend in average δ¹³C from the late middle Miocene to late Miocene can be explained by (1) gradual changes in local environmental conditions, and/or (2) increased amount of less mature specimens among the younger samples. In contrast, the highest obtained δ¹³C values were found in the youngest Pliocene ambers. Instead of maturation bias this can be linked to environmental factors such as cooler-drier climate with increased seasonality, probably reflecting the onset of the northern hemisphere glaciation.
... Some specimens show flow banding. Murray, Padley, McKirdy, Summons and Booth (1994) showed that the coastal ambers of South Australia are fragments of resin and fossilised resin (resinite) derived from tropical angiosperms of the family Dipterocarpaceae, of which there are 16 genera and around 500 species. These trees dominate the lowland forests of Southeast Asia but do not grow in Australia (Ashton, 1982;Paijmans, 1976). ...
... Their Cenozoic geographical range corresponds to the present distribution of extant species (Ashton, 1982). Pyrolysis of these coastal ambers yielded a series of isomeric bicadinanes (Murray et al., 1994), the same triterpenoid hydrocarbons found in three families of the waxy coastal bitumens (see Table 3) and in many Southeast Asian oils Teerman, Hwang, & Williams, 1987;Van Aarssen, Hessels, Abbink, & De Leeuw, 1992). ...
... In several places, large eddies swing the current into and away from the coastline (Rennie, Pattiaratchi, & McCauley, 2007). It is the SEC and LC that together transport the waxy bitumens, dammar resin and other flotsam (including tropical marine fauna such as the leatherback turtle found dead on the beach at Castle Cove, Victoria, in 1992: Padley, 1995) from their points of origin in Indonesia southwards into Australian waters Currie et al., 1992;McGowran et al., 1997;McKirdy et al., 1994;Murray et al., 1994). ...
The stranding of bitumen on ocean beaches in South Australia and western Victoria has been known for at least 170 years. In this review, we define what is meant by ‘coastal bitumen’, illustrate its different varieties, and present the results of the first quantitative geospatial survey of its occurrence in South Australia. We then summarise the distinguishing molecular and isotopic characteristics of six families of these ‘ocean wanderer’ bitumens, as pointers to their likely provenance.
A bimonthly survey of six South Australian beaches conducted during 1991–1992 identified three categories of stranded petroleum: waxy bitumen, asphaltite and oil slicks. Each is physically and chemically distinct and bears no resemblance to any crude oil so far discovered in Australia’s sedimentary basins. The maximum waxy bitumen loading of the beaches visited was 2 kg per 100 m. Accounting for 90% of the strandings, the waxy bitumens originate from oil seeps within the Indonesian Archipelago and are transported into southern Australian waters as flotsam by a complex system of surface ocean currents. The less common asphaltite is now understood to be a product of low-intensity seepage from tar mats exposed by the incision of submarine canyons into Australia’s southern continental slope. The oil slicks represent occasional spillage from local maritime traffic.
The stranding of petroleum along Australia’s southern coastline therefore can be attributed to both natural and anthropogenic causes. The recent commencement of a new phase of oil and gas exploration in the Great Australian Bight highlights the need to characterize and quantify these inputs to the hydrocarbon loading of the adjacent ocean beaches.
... Some specimens show flow banding. Murray, Padley, McKirdy, Summons and Booth (1994) showed that the coastal ambers of South Australia are fragments of resin and fossilised resin (resinite) derived from tropical angiosperms of the family Dipterocarpaceae, of which there are 16 genera and around 500 species. These trees dominate the lowland forests of Southeast Asia but do not grow in Australia (Ashton, 1982;Paijmans, 1976). ...
... Their Cenozoic geographical range corresponds to the present distribution of extant species (Ashton, 1982). Pyrolysis of these coastal ambers yielded a series of isomeric bicadinanes (Murray et al., 1994), the same triterpenoid hydrocarbons found in three families of the waxy coastal bitumens (see Table 3) and in many Southeast Asian oils Teerman, Hwang, & Williams, 1987;Van Aarssen, Hessels, Abbink, & De Leeuw, 1992). ...
... In several places, large eddies swing the current into and away from the coastline (Rennie, Pattiaratchi, & McCauley, 2007). It is the SEC and LC that together transport the waxy bitumens, dammar resin and other flotsam (including tropical marine fauna such as the leatherback turtle found dead on the beach at Castle Cove, Victoria, in 1992: Padley, 1995) from their points of origin in Indonesia southwards into Australian waters Currie et al., 1992;McGowran et al., 1997;McKirdy et al., 1994;Murray et al., 1994). ...
The stranding of bitumen on ocean beaches in South Australia and western Victoria has been known for at least 170 years. In this review, we define what is meant by coastal bitumen, illustrate its different varieties, and present the results of the first quantitative geospatial survey of its occurrence in South Australia. We then summarise the distinguishing molecular and isotopic characteristics of six families of these ocean wanderer bitumens, as pointers to their likely provenance. A bimonthly survey of six South Australian beaches conducted during 1991-1992 identified three categories of stranded petroleum: waxy bitumen, asphaltite and oil slicks. Each is physically and chemically distinct and bears no resemblance to any crude oil so far discovered in Australia's sedimentary basins. The maximum waxy bitumen loading of the beaches visited was 2kg per 100m. Accounting for 90% of the strandings, the waxy bitumens originate from oil seeps within the Indonesian Archipelago and are transported into southern Australian waters as flotsam by a complex system of surface ocean currents. The less common asphaltite is now understood to be a product of low-intensity seepage from tar mats exposed by the incision of submarine canyons into Australia's southern continental slope. The oil slicks represent occasional spillage from local maritime traffic. The stranding of petroleum along Australia's southern coastline therefore can be attributed to both natural and anthropogenic causes. The recent commencement of a new phase of oil and gas exploration in the Great Australian Bight highlights the need to characterise and quantify these inputs to the hydrocarbon loading of the adjacent ocean beaches.
... The distribution of s.g for the resinite fraction reported in Bodily and Kopp (1987) is also shown in Fig. 13. Long distance oceanic transport of Cenozoic resinite from Southeast Asia to the southern Australian coast is confirmed by geochemical fingerprinting (Murray et al., 1994). The s.g. of the five samples of coastal resinites and three reference samples given in Murray et al. (1994) are likewise shown in Fig. 13. ...
... Long distance oceanic transport of Cenozoic resinite from Southeast Asia to the southern Australian coast is confirmed by geochemical fingerprinting (Murray et al., 1994). The s.g. of the five samples of coastal resinites and three reference samples given in Murray et al. (1994) are likewise shown in Fig. 13. The compilation in Fig. 13 shows that the major part of measured s.g. of Kvaefjord coal compares with the lower part of the s.g. ...
... The compilation in Fig. 13 shows that the major part of measured s.g. of Kvaefjord coal compares with the lower part of the s.g. distribution from Bodily and Kopp (1987), and with the denser samples of coastal resinites from Murray et al. (1994). Sea water acts as a density separator for coals containing resinite, and only lumps with extremely high resinite content, such as the analysed samples from discoveries 18913[14 Fraena] and 18914[15 Tromsø] (Fig. 3A,B), will be capable of oceanic transportation. ...
... In earlier reports we have proposed new maturity indices based on changes in the isomeric distributions of bicadinanes, diaromatic secobicadinanes, diaromatic tricadinanes and cadalenes (Murray et al., 1994b;Sosrowidjojo et al., 1993Sosrowidjojo et al., , 1994Alexander et al., 1994), Almost all the Tertiary oils of Southeast Asia contain these and other compounds formed during catagenetic dissociation of polycadinene--a major constituent of resins exuded by some tropical angiosperms (van Aarssen et al., 1990(van Aarssen et al., , 1992(van Aarssen et al., , 1994Murray et al., 1994a). Smaller relative amounts of bicadinanes have also been found in oils and sediments from outside Southeast Asia and in samples of we-Tertiary age (Armanios et al., 1996;Summons et al., 1995;Murray et al., 1994b;van Aarssen et al., 1994). ...
... Compound T has been identified as trans-trans trans bicadinane (Cox et al., 1986) but the structures of compounds T1 and R are not known. However, since their mass spectra differ only slightly from that of compound T (Murray et al., 1994a), they are presumed to have the trans-transtrans ring configuration and to differ from compound T in the ring position or axial/equatorial location of the substituent groups. Another bicadinane maturity index, BMI-3, is based on the relative abundance of cis-cis-trans isomers (Murray et al., 1994b). ...
... First, Alexander et al. (1994) demonstrated that acid-clays promote the loss and transfer of the isopropyl group from cadalene in vitro and presented evidence that these reactions occur under natural conditions. Second, we have observed a homologous series of alkyl and des-alkyl bicadinanes in oils, resin pyrolysates and sediments (Murray et al., 1994a;Murray et al., in preparation) and preliminary observations suggest that their abundance is highest in shales. The factors which promote the removal or transfer of the isopropyl group do not appear to be the same as those associated with the formation of neohopanes, as we observe no correlation between TjTm and the abundance of des-isopropyl bicadinanes in oils. ...
Biomarker maturity indices have proven useful in petroleum exploration to assess the thermal maturity of oils and sediments. However, their application to deltaic petroleum systems is often hindered by source and diagenetic interferences. Recently, we have described several new maturity indices based on the catagenetic products of the plant biopolymer polycadinene. These indices should be largely immune to biochemical effects during diagenesis, since little microbial activity will remain at temperatures sufficient to dissociate the polymer.Here we report changes in five polycadinene-related maturity indices through a marine-fluvio-deltaic depositional sequence in the South Sumatra Basin, Indonesia. The results are compared with the maturity required for oil generation as estimated by kinetic modelling and with conventional maturity indicators such as sterane epimerisation and the methyl phenanthrene index. The data confirm that the polycadinene indices are less subject to source and diagenetic interferences than those based on the sterane and aromatic hydrocarbon distributions. Values for several of the indices have also been measured for 17 Tertiary oils from Southeast Asia, Papua New Guinea, New Zealand and Australia. Contrary to an earlier report, the bicadinane maturity indicator (BMI-1) continues to change into the oil window and hence may be useful in ranking the relative maturity of oils as well as sediments. The BMI-1 values for two oils having unusually low sterane maturities are normal, leading us to question whether the low sterane maturity of many Tertiary-age oils is due to their source rocks having been heated more rapidly than those of older oils.
... Bocherens et al., 1994 for a review of fossil plant data). However, a search of both the botanical and geological literature prior to embarking on this project (Murray et al., 1994a) revealed only two references to the carbon isotope composition of resinite: Rigby et al. (1981) and Smith et al. (1982) compared the d 13 C value of resinites in Australian coals with values obtained for other coal macerals. This de®ciency determined the broad aim of the present project which was to measure d 13 C for a range of resins and resinites and then to develop a better understanding of their natural variability and to explore how resin-derived hydrocarbons in¯uence the isotopic compositions of oils and oil-prone sediments. ...
... Fossil resin samples were obtained from the Yallourn open-cut coal mine, Victoria, Westport and Greymouth coal ®elds, New Zealand (courtesy of Dr J. Newman), Blind Canyon Mine, Utah, U.S.A. (courtesy of Dr A. Davis), outcrop coals on Jalan Sungei Akar, Bandar Seri Begawan, Brunei Darussalam) and as¯otsam on the Southern Australian coast (see details in Murray et al., 1994a). Further details of the origin, age (where known) and botanical anity of the resin and resinite samples are given in the tables of results. ...
... All d 13 C values are reported in the standard delta notation relative to the Pee Dee Belemnite (PDB). A sample of laboratory gradè`D ammar Resin'' (Fluka Pty) was previously measured at À26.5- (Murray et al., 1994a). Additional, individual pieces from the same batch showed slight colour variation and were subsequently measured at À27.8, À28.7 and À28.5thus showing that care must be taken to ensure that speci®c samples are representative and homogeneous. ...
Hydrocarbons derived from plant resins are major components of some terrigenous oils and bitumens. These compounds are structurally distinct and this makes them useful biomarkers applicable in petroleum exploration as well as sources of biogeochemical information about palaeoenvironment and palaeobotany. Although recent studies have elucidated the molecular structure of resinites, very little information has been available for the carbon isotope composition of resinites and no studies of resin-derived compounds in oils had been performed prior to the present study. Hence, carbon stable isotope analyses were carried out on a suite of modern and fossil resins of diverse origins, including compound specific isotope analysis of individual hydrocarbons produced during resin pyrolysis. Oils derived from resinitic source organic matter were also analysed. The results showed that “Class I” resinites derived from gymnosperms were enriched in the heavy carbon isotope compared with those from angiosperms (“Class II” resinites). Furthermore, both fossil resinites themselves and individual hydrocarbons derived from them were isotopically heavy compared with modern plant resins. The isotopic signatures of diterpanes and triterpanes in various early Tertiary oils from Australasia and Southeast Asia reflect their origins from gymnosperms and angiosperms, respectively.
... [207,208] Another plausible source of aromatic compounds is organic matter from the sediments, in which the resins were buried. [53,77,178,192,194,[209][210][211][212][213][214][215][216][217][218][219][220] The Table 3. Characteristic Raman bands of fossil resins and their assignments. ...
... [189,222] However, EEM of the resins is complex and very difficult in interpretation. [77,192,194,[209][210][211][212][213][214][215][216][217][218][219] The other substances and minerals present in natural resins may quench or adsorbed fluorescence emission from fluorescent compounds. The fluorescence of the material can be also altered by the natural weathering processes induced by light, heat and oxygen. ...
The review presents methods that are used frequently for multi-analytical study of fossil resins. The preliminary characterization relies on physical methods such as microhardness, density and fluorescence in UV light measurements. The spectroscopic methods: infrared spectroscopy, Raman spectroscopy, fluorescence spectroscopy are also presented in the paper. Besides that, the review also contains examples of the application of chromatographic methods: gas chromatography, thin layer chromatography, high-performance liquid chromatography, two-dimensional gas chromatography coupled to time-of-flight mass spectrometry as well as sample preparation methods for chromatographic studies such as pyrolysis. Additionally, thermal methods such as thermogravimetric analysis and differential scanning calorimetry also are covered by the review. Beside the examples of application, a detailed description with development history and perspective for further improvement are presented for each method. Moreover, fit-for-purpose assessment of each method is illustrated based on many examples from literature. The paper also contains examples of the application of multivariate statistical analysis and chemometric methods for comparing multiple properties of different fossil resin specimens for differentiation and classification purposes.
... This oceanic transportation pathway has previously been invoked to explain the occurrence of oils of apparent Indonesian origin arriving on the coastlines of Western Australia, South Australia and Victoria (Currie et al., 1992;McKirdy et al., 1994;Padley, 1995;Edwards et al., 2018). Further evidence that these currents transport flotsam from SE Asia is provided by the occurrence of fossilised tree resins (resinites) derived from tropical angiosperms of the family Dipterocarpaceae, which similarly strand along the South Australian coastline (Murray et al., 1994). Upon entering the Great Australian Bight, the oils are carried further by local ocean currents, in particular the Coastal Current (Fig. 1), which flows east during winter and west during summer, consistent with the observed lower abundance of coastal bitumen strandings in the summer months (Edwards et al., 2018). ...
... Furthermore, although numerous minor shipping incidents were reported, no large oil discharges or spills occurred in proximity to the paths of the currents along the Western Australian or South Australian coastline during the study period which might otherwise account for the oils described herein (Australian Maritime Safety Authority, 2014, 2015. Given the lack of significant anthropogenic sources of oil, and the fact that the majority of the stranded oils have atypical biomarker signatures similar to those of SE Asian oils, a region where numerous seafloor seeps are recognised (Macgregor, 1993;Orange et al., 2009;Noble et al., 2009) and welldocumented ocean currents (Gordon, 2005;Middleton and Bye, 2007;Gordon et al., 2012;Susanto et al., 2016) are known to transport material (Murray et al., 1994;McGowran et al., 1997), we consider all of the oils documented herein to originate from natural seepage. ...
In 2014–2016 more than 600 specimens of semi-solid crude oil were recovered from 30 ocean beaches along the coastline of South Australia, as part of the recently completed Great Australian Bight Research Program. All are believed to be products of submarine oil seepage. Their source-specific biomarker signatures provide the basis for their assignment to sixteen oil families, some previously unrecognised. Two of these families (asphaltite and asphaltic tar) likely originated from Cretaceous marine source rocks in the offshore Bight Basin. The others comprise waxy oils of lacustrine, fluvio-deltaic and marine source affinity. Their biomarker characteristics do not match those of any Australian crude oil. However, they are strikingly similar to those of oils found in Cenozoic and Mesozoic basins throughout the Indonesian Archipelago and elsewhere in Southeast Asia.
... Les composantes polymériques ou macromoléculaires peuvent être natives, c'est-à-dire présentes initialement dans les différents ingrédients employés pour préparer les substances organiques trouvées en contexte archéologique. On peut notamment évoquer les bitumes dont certains constituants peuvent atteindre 10 000 Da (Hellmuth, 1989) ou certaines résines comme par exemple les résines de Dipterocarpaceae composées de constituants polymériques basés sur des sous-unités de type cadinène (Van Aarssen et al., 1990a, 1990bMurray et al., 1994). Mais il est également possible que certaines de ces composantes polymériques ou macromoléculaires soient issues de réactions de condensation/polymérisation impliquant les composés de bas poids moléculaire intervenant pendant une activité de préparation faite par l'Homme (e.g. ...
... Ce des-A-triterpène, qui n'a jamais été décrit dans la littérature auparavant, constitue potentiellement un nouveau biomarqueur d'altération des résines de Dipterocarpaceae en conditions anaérobies. Ces composés correspondent à des analogues di-et trimériques des polymères de cadinène qui constituent la fraction macromoléculaire des résines de dammar (Van Aarssen et al., 1990a, 1990bMurray et al., 1994). (Stout, 1996). ...
Cette thèse a été consacrée à la problématique de l’altération de substances organiques en contexte archéologique, avec pour objectifs de donner des clés analytiques et expérimentales pour étudier les processus mis en jeu, d’identifier de nouveaux outils moléculaires indicateurs des processus subis par les matériaux organiques archéologiques et d’interpréter l’impact de ces processus sur les signatures moléculaires de ces matériaux. Après la mise au point d’un protocole expérimental de vieillissement en laboratoire reproduisant les processus « naturels » de vieillissement de substances organiques archéologiques, nous avons déterminé que les réactions croisées entre ingrédients (esters d’acides gras, terpènes) conduit à la formation de composés oligo-/polymériques intéressants à étudier à l’aide de réactions de dégradation chimique. L’étude moléculaire de matériaux organiques archéologiques a aussi été abordée. Ainsi, de la résine de diptérocarpacées provenant de deux épaves asiatiques du XIIème siècle et du brai de bouleau utilisé pour réparer des céramiques néolithiques ont été identifiés. De nouveaux biomarqueurs triterpéniques d’altération issus de la dégradation anaérobie en milieu sédimentaire de triterpènes précurseurs (résine), et des biomarqueurs de traitement thermique intense (brai) ont été caractérisés.
... New Zealand, Australia, Philippines and Papua New Guinea) and in samples of pre-Tertiary age (Murray et al., 1994b; van Aarssen et al., 1994; Armanios et al., 1995 ). Although the tropical angiosperm family Dipterocarpaceae is not the only angiosperm from which sedimentary bicadinanes can be derived (Murray et al., 1994a; van Aarssen et al., 1994; Armanios et al., 1995), it is suggested that the bicadinanes enriched in the Tertiary oils of Southeast Asia are associated with dammar resins from Dipterocarpaceae plants (van Aarssen et al., 1990a; Murray et al., 1994a). Remnants of these plants only occur in rocks of Oligocene or younger age (e.g. ...
... New Zealand, Australia, Philippines and Papua New Guinea) and in samples of pre-Tertiary age (Murray et al., 1994b; van Aarssen et al., 1994; Armanios et al., 1995 ). Although the tropical angiosperm family Dipterocarpaceae is not the only angiosperm from which sedimentary bicadinanes can be derived (Murray et al., 1994a; van Aarssen et al., 1994; Armanios et al., 1995), it is suggested that the bicadinanes enriched in the Tertiary oils of Southeast Asia are associated with dammar resins from Dipterocarpaceae plants (van Aarssen et al., 1990a; Murray et al., 1994a). Remnants of these plants only occur in rocks of Oligocene or younger age (e.g. ...
Triterpanes and steranes in condensates from the YA13-1 gas field, Qiongdongnan Basin, were monitored. The YA13-1
condensates have unusual biomarker distributions dominated by terpanes and steranes derived from higher plants. Anomalously
abundant 18a-oleanane and remarkably abundant bicadinanes are present in the YA13-1 condensates, whereas the 17a-hopane
contents are extremely low. Taraxastane and significantly abundant 17a-diahopanes occur in the condensates. In addition, a
number of unknown C29 and C30 pentacyclic triterpanes including previously unreported compounds were detected in the
condensates, some of which are significantly abundant. The unknown compounds may be terrestrial biomarkers. C29
homologues are relatively predominant among the regular and rearranged steranes. The diasterane concentrations are markedly
higher than those of regular steranes. The maturity of the YA13-1 condensates is relatively high, at the peak to late oil
generation stage (corresponding to 0.85–1.10% Ro), based on sterane and terpane and including bicadinane maturity
parameters (i.e. T/(T1 + R) and T/R bicadinane ratios). The above maturity assessment result is different from that based on
diamondoid maturity parameters (%Ro = 1.60–1.70) [Org. Geochem. 25 (1996) 179], which can be explained by a contribution
of hydrocarbons from two sources at different depths. The YA13-1 condensates were probably generated from the Yacheng and
Lingshui coal-bearing source rocks buried both in the Qiongdongnan Basin (3400–5000 m) and in the Yinggehai Basin (>5000
m). The possible contribution of lower maturity hydrocarbons from the Yacheng and Lingshui Formations (3400–4100 m) in
the Qiongdongnan Basin to the YA13-1 gases and condensates should not be neglected.
... Methylbicadinane and four isomers of bicadinane were identified in the Family 1 waxy bitumens (Fig. 8). Using the nomenclature of Summons et al. (1993) and Murray et al. (1994a), the C 30 bicadinane isomers are labelled W, T, T1 and R, respectively; and the methylated bicadinane isomers of T and T1, are annotated as MeT and MeT1, respectively. Typically, the relative abundance of bicadinane isomers in Family 1 waxy bitumens is T > T1 > R > W (parameter 16, Table 4b). ...
... Oleanane first appeared during the Late Cretaceous (late Campanian), but high concentrations of this pentacyclic triterpane have only been observed in Cenozoic sediments and oils, corresponding to the time when angiosperms became the dominant flora. Bicadinane has been identified in Cenozoic oils throughout Indonesia, southern China, Papua New Guinea, the Philippines and New Zealand (van Aarssen et al., 1990;Murray et al., , 1994aMurray et al., , 1994b. However, high concentrations of bicadinane appear to be confined to Cenozoic sediments and associated oils from Southeast Asia. ...
Reports of bitumen stranding on the ocean beaches of southern Australia date back to the early days of European settlement. Previous investigations have shown that this ‘coastal bitumen’ comprises three categories of stranded petroleum: waxy bitumen, asphaltite and oil slicks. All three varieties are physically and chemically distinct from each other, and bear no geochemical resemblance to any indigenous Australian crude oil. This study focuses on the most common variety, waxy bitumen, which accounted for 90% of the strandings on six South Australian beaches repeatedly surveyed during 1991–1992. Geochemical analysis of 96 individual specimens collected from these survey sites and other beaches in South Australia and western Victoria has shown them to be variously weathered high-wax crude oils of paraffinic to aromatic-intermediate bulk composition. Elemental, isotopic and biomarker differences allow their assignment to at least five oil families with inferred source facies that range from deep freshwater lacustrine through paludal and deltaic to euxinic marine, possibly deposited within different sedimentary basins. Family 1, 2 and 3 waxy bitumens all contain biomarkers derived from the freshwater alga Botryococcus sp. and tropical angiosperms (notably dipterocarps). Similar biomarker assemblages are unknown in Australian sedimentary basins but are common in Cenozoic crude oils and source rocks throughout western Indonesia. Family 4 waxy bitumens lack these biomarkers, but do contain dinosterane and 24-n-propylcholestane, indicative of a marine source affinity, while the carbon isotopic signatures and high pristane/phytane (Pr/Ph) ratios of Family 5 waxy bitumens are consistent with their origin from coal-rich source rocks deposited in fluvial to deltaic sedimentary successions. The majority of these waxy bitumens represent an oceanic influx of non-indigenous, Southeast Asian crude oils carried into the waters of southern Australia by the Leeuwin Current. Although they are likely to originate from natural seepage within the Indonesian Archipelago, it is unknown whether the parent oils emanate from submarine seeps or from inland seepages which are then carried to the sea by rivers. The common practice of tanker cleaning operations in the Java and Banda seas may augment the supply of natural bitumen to the beaches of Australia.
... The bicadinanes W, T, T1 and R were assigned in HPLC fractions from an Assam Basin oil (sample code 2007004-14601) and a Niger Delta oil (sample code 2007004-14449) by comparison with mass spectra in the literature (Grantham et al., 1983; Alam and Pearson, 1990; van Aarssen et al., 1990 van Aarssen et al., , 1992 Murray et al., 1994b ). Structures of bicadinanes T and W (P and Q) have been determined by means of NMR (Cox et al., 1986; van Aarssen et al., 1990). ...
... Both oils contain an unidentified bicadinane with a bicadinane T-like mass spectrum (denoted as ''T? " in Figs. 4 and 5). Murray et al. (1994b) detected a bicadinane (W2) having a similar relative retention time but with a mass spectrum resembling that of W. Bicadinanes are particularly abundant in crude oils from southeast Asia (van Aarssen et al., 1992) and GC–MS–MS analysis of the oils in Table 1 (412 ? 369, C 30 bicadinanes only) also showed the highest relative concentrations in the Lufa Seep from Papua New Guinea and the Kutei Basin oils, followed by the Assam Basin oils and the two oils from Vietnam. ...
a b s t r a c t The three most abundant rearranged oleanoid triterpanes eluting early in gas chromatography (GC) have been isolated from a Niger Delta oil and characterized using nuclear magnetic resonance (NMR) spectros-copy. The NMR data confirmed the identification of two of them, observed previously in the literature, as 1(10 ? 5)abeo-3b-methyl-24b-nor-18a(H)-oleanane and 5(4 ? 3)abeo-3a(H), 5b(Y), 18a(Y)-oleanane on the basis of X-ray crystallography and comparison with a synthetic standard. The third compound was a novel rearranged oleanane, 3a,5b-dimethyl-23a,25-dinor-10b(H),18a(H)-oleanane, with one of the methyl groups at C-4 in the oleanane structure shifted to C-3 and another shifted from C-10 to C-5. The distribution of these three rearranged oleananes and other, yet unidentified, rearranged oleanoid C 30 triterpanes in 25 Late Cretaceous-or Tertiary-sourced oils from Angola, Canada, Greece, India, Indo-nesia, Iran, New Zealand, Nigeria and Vietnam was examined by way of reverse phase high pressure liquid chromatography (HPLC), GC–mass spectrometry (GC–MS) and GC–MS–MS. Mass spectra of rear-ranged oleananes and compounds tentatively assigned as rearranged taraxastanes are presented. Rear-ranged oleananes and other rearranged triterpanes are probably formed by dehydration and rearrangement of higher plant triterpenoids functionalized at C-3. The distribution of rearranged olean-anes and their relative concentration seems to be dependent on the extent of clay catalysis during dia-genesis. A diagenetic pathway for formation of the rearranged oleananes is proposed. All 25 oils have almost identical rearranged oleanane/oleanane and diasterane/regular sterane ratio values. Two uniden-tified early eluting (GC) rearranged oleananes are only abundant in oils with a high proportion of diaster-anes. Bicadinanes were found in 20 of the 25 oils.
... Further evidence of this oceanic transportation pathway is provided by strandings of fossilised tree resins (resinites) along the South Australian coastline. These originate from tropical hardwoods not found in Australia, but common throughout SE Asia (Murray et al., 1994). ...
Crude oil released from natural offshore seeps may strand in coastal environments. Understanding the different types of oil which accumulate on a given coastline, in addition to their spatial distribution and abundance, may be used to establish an environmental baseline for natural “background” petroleum contamination. Here we summarise the hydrocarbon loading of thirty beaches on Australia's southern margin based on three annual surveys in 2014–2016. Comparison with the results of surveys conducted in 1990 and 1991 reveals a marked reduction in hydrocarbon loading. Furthermore, modern samples of the most commonly encountered oil, attributed to a lacustrine petroleum system in the Indonesian Archipelago, are significantly more degraded than those of prior studies. We attribute this reduction in hydrocarbon loading to prolonged oil production in Southeast Asia, which in turn results in reduced reservoir pressures and the eventual cessation of formerly active offshore seepage.
... Polymers of cadalanes (i.e., bicadinanes, polycadinenes) have been found in the angiosperm dammar resins of the family Dipterocarpaeae, a tropical hardwood (van Aarssen et al. 1990). These resins were found to be responsible for much of the crude oil discovered in South-East Asia and Australia (Murray et al. 1994). Dutta et al. (2009Dutta et al. ( , 2011 reported the occurrence of bicadinanes typical of dammar resin within Eocene lignites from India, providing evidence for the first appearance of Dipterocarpaceae angiosperms during the early Eocene and the subsequent out-of-India dispersal of Asian dipterocarps. ...
Peat depositional environments, the sites where and conditions under which peat accumulates, significantly influence a resultant coal's physical properties, chemical composition, and coal utilization behavior. Recognition of peat depositional environments for coal is a challenging endeavor because coal's observed compositional properties not only result from a variety of geological processes operating during peat accumulation, but also reflect the influence of adjoining or external depositional sedimentary environments and alteration during later diagenesis and/or epigenesis. The maceral or microlithotype composition of any one layer of peat can be the product of years or decades of plant growth, death, decay, and post-burial infiltration by roots in addition to the symbiotic, mutualistic, parasitic, and saprophytic relationships with non-plant biota, such as arthropods, fungi, and bacteria. The overprint of increasing thermal maturation and fluid migration through time on the resulting coal can make these relationships difficult to recognize. Therefore, published models based on maceral composition alone must be used with great caution. Lipid compositions, even from lipid-poor low-rank coals, can provide important information about depositional environments and paleoclimate, especially if combined with the results of organic petrography and paleontological studies. Just as sulfur derived from seawater provides environmental clues, the ratios of two particularly relevant trace elements rather than a single trace element can be used to interpret peat depositional environments. Epigenetic minerals, as well as their corresponding chemical compositions should not be used for such a purpose; similarly, resistant terrigenous minerals deposited during peat accumulation in many cases should be used with considerable caution. The interactions of the biota present in the peat-forming ecosystem, often determined using palynological and geochemical proxies, and their interpretation in the context of geography and paleoclimate are important means for deciphering peat depositional environments. Overall, a combination of evidence from geochemistry, mineralogy, palynology, and petrology of coal and from stratigraphy, sedimentology, and sedimentary facies of related rocks is necessary for accurate and comprehensive determination of depositional environments. The need for interdisciplinary studies is underscored by peat compositional properties, which have been greatly affected by various processes during the syngenetic, diagenetic or epigenetic stages of coal formation.
... Nouvelle-Zélande, de certains copals et de l'ambre balte (Colchester et al., 2006 (Murray et al., 1994). ...
Les travaux de cette thèse portent sur la caractérisation chimique des ambresprovenant de plusieurs gisements d’âges et d’origines géographiques variés, dont certains sontinédits. Des protocoles identiques à tous les échantillons et combinant les analysesspectroscopiques (IR et RMN 13C) et chromatographiques (THM-CPG-SM) ont été appliqués,permettant d’identifier l’origine botanique des ambres et fournissant des indices pour lareconstitution des paléoenvironnements terrestres.La caractérisation chimique des gisements d’ambre du Jurassique supérieur(Kimméridgien) jusqu’au Crétacé supérieur (Santonien) du Liban, de Jordanie, du Congo,d’Equateur et de France, permet de proposer des biomarqueurs pour les résines deCheirolepidiaceae, une famille exclusivement mésozoïque de Conifères. Une évolution dessources botaniques des résines produites durant le Mésozoïque et le Cénozoïque est alorsdiscutée. Une production dominée par les familles de Conifères Araucariaceae etCheirolepidiaceae est remarquée au Jurassique supérieur et Crétacé inférieur. La productionau Crétacé supérieur est plutôt dominée par des Cupressaceae. Au Cénozoïque, les originesbotaniques des ambres sont plus variées, et des familles d’Angiospermes sont à l’origine denombreux gisements, dont l’ambre du Pérou produit par une Fabaceae. La production par desConifères reste toutefois importante au Tertiaire, à l’exemple des ambres de Nouvelle-Zélande qui ont pour origine les Araucariaceae.Les données obtenues ont permis une ré-évaluation de la classification des ambres parPy-GC-MS. Ainsi, une nouvelle molécule dont la structure est inconnue encore, a étéidentifiée dans les chromatogrammes d’ambres de classe Ib et Ic, ajoutant un caractèrediscriminant entre ces deux sous-classes.Enfin, la relation âge / maturation des résines fossiles est discutée, qui dépend avanttout des conditions d’enfouissement des résines.Une large base de données moléculaires est ainsi établie pour un grand nombre degisements d’âges et d’origines botaniques variés, qui permettra une comparaison globale dansles travaux futurs.
... Polymers of cadalanes (i.e., bicadinanes (XVII; Fig. 1), polycadinenes (XVIII, Fig. 1)) have been found in the angiosperm dammar resins of the family Dipterocarpaceae, a tropical hardwood (van Aarssen et al. 1990). These resins were identified to be responsible for much of the crude oil found in Southeast Asia and Australia (Murray et al. 1994). ...
... However, Dipterocarpaceae is absent from both the macrofossil and pre-Quaternary pollen record (Christophel, 1989), and modern biota (Ashton, 1982), of Australia. Previous studies on Australian Class II amber from the beaches of South Australia (Murray et al., 1994) and Cape York, northern Australia (Sonibare et al., 2014), reconciled this by proposing that the amber was transported by ocean currents from a dipterocarpaceous source in Southeast Asia, although the source areas have not yet been confirmed. This mechanism of deposition is considered highly unlikely at Anglesea, the only locality of the present study where Class II amber was found, for the following reasons: ...
Amber is a complex, organic polymer that offers unparalleled utility as a preservation medium, providing insights into past organisms and environments. However, under specific circumstances, this information can be compromised through alteration of the amber structure. Understanding the degradation of amber in the geosphere could improve prospecting techniques and maximise the quality and validity of chemical information from altered samples. This study analysed 114 amber samples retrieved from two new Eocene Australian deposits at Strahan, Tasmania and Anglesea, Victoria using a combination of attenuated total reflectance Fourier transform infrared and solid-state ¹³C cross-polarised magic angle spinning nuclear magnetic resonance spectroscopy. Results identified both Class Ib polylabdanoid and Class II cadinene-based amber. The presence of Class II amber in Australia suggests one of two possibilities: (1) a local Dipterocarpaceae source, the primary producer of Class II resins, despite the absence of this family from the Australian Eocene fossil record; or (2) a local, unidentified botanical source of cadinene-based amber. A third alternative, that Class II amber was transported to Australia from Southeast Asia via ocean currents, is rejected. Taphonomic analysis revealed four mechanisms of alteration prevalent in amber across the two study regions, with evidence of oxidation and metal carboxylate formation. Both the nature and extent of these alterations were found to vary significantly between classes I and II, suggesting that amber class may play a defining role in determining the chemical pathways by which amber degrades. Of note was the high proportion of amber that exhibited no significant chemical changes despite extensive visible alteration features, suggesting the integrity of palaeobiological and palaeoenvironmental information in these samples may be preserved.
... It is resistant to diagenesis and can maintain its original chemical and isotopic composition and for this reason is thought to be a very powerful tool for reconstruction of the palaeoatmosphere and the palaeoenvironment (Murray et al., 1998;McKellar et al., 2011;Dal Corso et al., 2011Aquilina et al., 2013;Tappert et al., 2013). It has been shown that amber d 13 C (d 13 C AMBER ) falls in the range of typical modern C3 plants and may reveal information about climate and environment at the time of resin exudation, for example changes in plant carbonisotope discrimination linked to environmental stresses such as insect infestation or water availability (Murray et al., 1994(Murray et al., , 1998Nissenbaum and Yakir, 1995;McKellar et al., 2008McKellar et al., , 2011Dal Corso et al., 2011Tappert et al., 2013). However, contrary to that of wood and leaf, less research has focused on developing amber as a palaeoatmosphere proxy (Tappert et al., 2013). ...
During the mid-Cretaceous, angiosperms diversified from several nondiverse lineages to their current global domination [1], replacing earlier gymnosperm lineages [2].Several hypotheses explain this extensive radiation [3], one of which involves proliferation of insect pollinator associations in the transition from gymnosperm to angiosperm dominance. However, most evidence supports gymnosperm–insect pollinator associations, buttressed by direct evidence of pollen on insect bodies, currently established for four groups: Thysanoptera (thrips), Neuroptera (lacewings), Diptera (flies), and now Coleoptera (beetles). Each group represents a distinctive pollination mode linked to a unique mouthpart type and feeding guild [4–9]. Extensive indirect evidence, based on specialized head and mouthpart morphology, is present for one of these pollinator types, the long-proboscid pollination mode [10], representing minimally ten family-level lineages of Neuroptera, Mecoptera (scorpionflies), and Diptera [8, 10, 11]. A recurring feature uniting these pollinator modes is host associations with ginkgoalean, cycad, conifer, and bennettitalean gymnosperms. Pollinator lineages bearing these pollination modes were categorized into four evolutionary cohorts during the 35-million year-long angiosperm radiation, each defined by its host-plant associations (gymnosperm or angiosperm) and evolutionary pattern (extinction, continuation, or origination) during this interval [12]. Here, we provide the first direct evidence for one cohort, exemplified by the beetle Darwinylus marcosi, family Oedemeridae (false blíster beetles), that had an earlier gymnosperm (most likely cycad) host association, later transitioning onto angiosperms [13]. This association constitutes one of four patterns explaining the plateau of family-level plant lineages generally and pollinating insects specifically during the mid-Cretaceous angiosperm radiation [12].
... It is resistant to diagenesis and can maintain its original chemical and isotopic composition and for this reason is thought to be a very powerful tool for reconstruction of the palaeoatmosphere and the palaeoenvironment (Murray et al., 1998;McKellar et al., 2011;Dal Corso et al., 2011Aquilina et al., 2013;Tappert et al., 2013). It has been shown that amber d 13 C (d 13 C AMBER ) falls in the range of typical modern C3 plants and may reveal information about climate and environment at the time of resin exudation, for example changes in plant carbonisotope discrimination linked to environmental stresses such as insect infestation or water availability (Murray et al., 1994(Murray et al., , 1998Nissenbaum and Yakir, 1995;McKellar et al., 2008McKellar et al., , 2011Dal Corso et al., 2011Tappert et al., 2013). However, contrary to that of wood and leaf, less research has focused on developing amber as a palaeoatmosphere proxy (Tappert et al., 2013). ...
Stable carbon-isotope geochemistry of fossilized tree resin (amber) potentially could be a very useful tool to infer the composition of past atmospheres. To test the reliability of amber as a proxy for the atmosphere, we studied the variability of modern resin δ¹³C at both local and global scales. An amber δ¹³C curve was then built for the Cretaceous, a period of abundant resin production, and interpreted in light of data from modern resins. Our data show that hardening changes the pristine δ¹³C value by causing a ¹³C-depletion in solid resin when compared to fresh liquid–viscous resin, probably due to the loss of ¹³C-enriched volatiles. Modern resin δ¹³C values vary as a function of physiological and environmental parameters in ways that are similar to those described for leaves and wood. Resin δ¹³C varies between plant species and localities, within the same tree and between different plant tissues by up to 6‰, and in general increases with increasing altitudes of the plant-growing site. We show that, as is the case with modern resin, Cretaceous amber δ¹³C has a high variability, generally higher than that of other fossil tissues. Despite the high natural variability, amber shows a negative 2.5–3‰ δ¹³C trend from the middle Early Cretaceous to the Maastrichtian that parallels published terrestrial δ¹³C records. This trend mirrors changes in the atmospheric δ¹³C calculated from the δ¹³C and δ¹⁸O of benthic foraminiferal tests, although the magnitude of the shift is larger in plant material than in the atmosphere. Increasing mean annual precipitation and pO2 could have enhanced plant carbon-isotope fractionation during the Late Cretaceous, whereas changing pCO2 levels seem to have had no effect on plant carbon-isotope fractionation. The results of this study suggest that amber is a powerful fossil plant material for palaeoenvironmental and palaeoclimatic reconstructions. Improvement of the resolution of the existing data coupled with more detailed information about botanical source and environmental growing conditions of the fossil plant material will probably allow a more faithful interpretation of amber δ¹³C records and a wider understanding of the composition of the past atmosphere.
... Long-range transportation is facilitated owing to low specific gravities of ambers, which allow them to float easily, as seen around the North Sea and Baltic Sea. This has been invoked previously for resinites found along the southern Australian coast (Murray et al. 1994). ...
The terpenoid composition of fossil resin from the Cape York Peninsula, Australia has been analysed by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) to determine its origin. The pyrolysis products were dominated by cadalene-based C15 bicyclic sesquiterpenoids including some C30–C31 bicadinanes and bicadinenes typical of Class II resin derived from angiosperm plants of Dipterocarpaceae. This observation contrasts with the Araucariaceae (Agathis sp.) source previously suggested for the resin based on Fourier transform infrared (FTIR) analyses. Dipterocarpaceae are not known in Australian vegetation but grow abundantly in Southeast Asia including New Guinea, indicating that the geological origin of the amber is not the Australian mainland but could be traced to Southeast Asia.
... Barclay et al., 2010) have been analyzed to reconstruct δ 13 C org trends, infer carbon-cycle perturbations and evaluate the carbon-isotope composition of atmospheric CO 2 in the past. Additionally, a few papers have explored the carbon-isotope signature of amber, pointing out that such analysis of fossil resin could be a useful tool for palaeobotanical, palaeoclimatic and palaeoenvironmental purposes: existing data show that amber has δ 13 C values similar to those expected for C 3 plants and seems to retain its original carbon-isotope signature (Murray et al., 1994;Nissenbaum and Yakir, 1995;Murray et al., 1998;McKellar et al., 2008;Stern et al., 2008). ...
The carbon-isotope signatures of Carnian (Late Triassic) amber drops from Rifugio Dibona (Southern Alps, Italy) were studied and compared with that of other Middle-early Late Triassic fossil plant remains, namely wood and leaves. Amber, wood and leaf carbon-isotope data are highly variable within the same beds. δ 13 C amber values vary by up to 5.4‰ and are enriched by ~ 2.5‰ with respect to associated wood. δ 13 C wood and δ 13 C leaf ranges are narrower than that of amber (~ 2–3‰) and the isotopic offset within each bed is similar over time. The high Triassic amber carbon-isotope variability is similar to that of recent resin. Despite the high variability, δ 13 C wood and δ 13 C leaf illustrate a Middle-early Late Triassic secular positive trend that is similar to that of marine δ 13 C inorg data and must record the carbon-isotope evolution of the ocean–atmosphere system.
... These studies provide excellent evidence that resins have the potential to retain their original characteristic isotopic signature. In another study (Murray et al. 1994), carbon isotopic ratios from two resinites washed ashore on the southern coast of Australia were compared to reference samples. Both isotopic and molecular evidence showed that the resinites most closely resemble both fossil and recent dammar from South-East Asia but not Australia. ...
We have applied and refined methods for the determination of bulk hydrogen, carbon and oxygen isotope ratios in modern and archaeological resins. The modern resins have a wide range of isotopic values and vary within the same tree, between individual trees, with species and location. For all isotopes measured, there is a general trend of increasing depletion of the heavier isotope with increasing altitude. There is also a linear trend between depletion of δD and δ13C values with increasing latitude; this trend is less clear for oxygen, but is related to the meteoric water line. Two case studies using archaeological resins known or suspected to have been transported in antiquity have been investigated to determine whether isotopic signatures can assist in pinpointing the geographical origin of the resin: Pistacia sp. resin from Canaanite amphorae imported into Egypt from known geographical locations in the eastern Mediterranean during the Late Bronze Age, and Roman amphorae sherds lined with Pinus sp. resin from sites ranging from Britain to the eastern Mediterranean. These results show separate groupings between the two resin types (pine/pistacia) and between the modern/archaeological resins. Some archaeological samples are distinct from the others and the modern resins show differences between geographical areas. However, there are no clear patterns relating the different Canaanite fabrics or the suggested manufacturing site of the Roman amphorae.
... Currie et al., 1992;Volkman et al., 1992;Summons et al., 1993;McKirdy et al., 1994). Currie et al. (1992) proposed long distance transport by ocean currents to account for the presence of geochemical signatures that were unambiguously endemic to the Indonesian Archipelago and this is supported by other work showing long-distance ocean transport of plant resins from SE Asia to southern Australia (Murray et al., 1994). ...
Sediment traps were deployed on the Northwest Shelf (NWS) of Australia in November 1996, to determine fluxes of organic matter and inorganic elements from the photic zone to deeper waters transecting the Exmouth Shelf to Exmouth Plateau. Dry weight fluxes from the traps ranged from 124 to 616 mg m−2 day−1 and POC fluxes ranged from 22.8 to 43.9. The biogenic hydrocarbons consisted of biomarkers indicative of marine zooplankton, phytoplankton and bacteria. GC analyses also revealed a significant component of petroleum-derived hydrocarbons through the presence of an unresolved complex mixture (UCM) that was approximately 4 times the biogenic hydrocarbon flux at shallow stations and up to 7 times at the most offshore station. The molecular characteristics of these hydrocarbons were investigated using GC-MS and GC-MS-MS and compared with local and regional petroleum accumulations. GC-MS analysis showed the hydrocarbons included n-alkanes, alkylated aromatics plus hopane and sterane biomarkers indicating a mature and moderately degraded crude oil. The sterane and triterpane signatures also indicated that the source rock of this oil was marine sediment with a calcareous lithology and of probable Mesozoic age. Commercially exploited oils of similar composition are mostly not known on the NWS. However, there are indications that there is an active petroleum system with some similar characteristics in the southern Carnarvon Basin as shown by oils of anomalous composition to the Chervil, North Herald and South Pepper fields. These results indicate that exploration strategies in the region should not be confined to oil reserves based on the Upper Jurassic Dingo claystone source.
... Bitumens collected from the Northern Territory tend to be highly weathered compared to those from temperate latitudes which can contain n-alkanes ranging between C 16 and C 35 (Dowling et al., 1995). Long distance oceanic transport is supported by the record of dammar resins washed ashore on the southern Australian coast, as far east as Wonthaggi in Victoria (Murray et al., 1994). The 'waxy bitumens' are interpreted to be derived from natural oil seeps in Indonesia and are transported to southern waters by the Leeuwin current (Currie et al., 1992). ...
Surprisingly few natural hydrocarbon seeps have been identified in Australia's offshore basins despite studies spanning thirty years. Early studies of natural hydrocarbon seepage around the Australian margin were generally based on the geochemical analysis of stranded bitumens, water column geochemical ‘sniffer’ sampling, synthetic aperture radar or airborne laser fluorosensor. Later studies involved the integration of these remote sensing and geochemical techniques with multi-channel and shallow seismic. A review of these earlier studies indicates that many seepage interpretations need to be re-evaluated and that previous data sets, when placed in a global context, often represent normal background hydrocarbon levels. Low Recent burial and subsidence rates are not favourable for high rates of seepage. There are also difficulties in proving seepage on high energy, shallow carbonate shelves, where seabed features may be rapidly re-worked and modern marine signatures are overprinted on authigenic seep carbonates. Thus, the relatively few sites of proven natural hydrocarbon seepage in Australia's offshore sedimentary basins can be reconciled relative to their geological occurrences and the dominantly passive margin setting. Active thermogenic methane seepage on the Yampi Shelf, the only proven documented occurrence in Australia, is driven by deposition of a thick Late Tertiary carbonate succession and Late Miocene tectonic reactivation. Therefore, to increase the success of detecting and correctly interpreting natural hydrocarbon seepage, data need to be analysed and integrated within the context of the local geological setting, and with an understanding of what is observed globally.
... These oils enter the ocean via rivers or submarine oil seeps. Geochemically, the coastal ambers are very similar in composition to both extant and fossil southeast Asian dammars, with their pyrolysates containing an isomeric series of bicadinanes ( Murray et al., 1994). They do not resemble either modern or fossil kauri resins. ...
The Leeuwin Current can be tracked from the western margin of the Australian continent to the southern margin by the record of fossilized organisms typical of warm-water marine environments. This transport smudges the normal latitudinal asymmetry in the biotas of opposing oceanic and continental margins, in which the eastern margins of oceans are cooler than the western margins and warmer biotas are restricted to lower latitudes in the east. The most comprehensive record is in the large benthic foraminifera, although fossils of benthic invertebrates, nektonic nautiloids and planktonic protists are also informative. In addition, organic biomarker hydrocarbons in stranded bitumens and resins demonstrate that they have travelled the same route from their ultimate sources in Cenozoic sedimentary basins and modern tropical rainforests of the Indonesian Archipelago. The earliest spoor of the current is in the later middle Eocene, at which time the part-deflection of counter-gyral circulation in the Indian Ocean to the southeast was stimulated by the accelerated opening of the oceanic gap between Australia and Antarctica. Thus the origin of the Leeuwin Current is twice the age of the previously suggested origin in the Miocene. The current turns on and turns off in the Great Australian Bight during the late Quaternary in concert with the interglacials and the glacials at scales of 105 yr. The switch can be seen in the faunal succession of planktonic foraminifera which are consistent with the neritic benthic faunas of the central gulfs: both communities show that, at the warm peak of the last interglacial, the current transported biota across the Bight more strongly than it has during the Holocene. The Cenozoic record of the past 40 Ma is in the same mode at 106 yr scales: the relevant fossils are found concurrently at major marine transgressions and warming reversals of the overall fall in global temperature. However, the fossil pattern is due to transport on the activated Leeuwin Current, not merely to general warming and the spread of friendly environments to higher latitudes.
... Furthermore, Murray et al. (1994) proved long-distance oceanic transport of fossil resin nodules. ...
A resin nodule was found in glauconite-rich detrital sediments of the Cretaceous Garschella Formation (Aptian to Albian) outcropping at Langer Köchel (Bavaria, S Germany). Gas chromatographic and mass spectrometric analyses of the fossil resin revealed dealkylation and the total defunctionalisation of its polycyclic constituents. Besides many unspecific components a specific one, agathalene, has survived. Agathalene also presents a strongly degraded product, but may have been derived from its natural precursor agathic acid, which is a very specific constituent (biomarker) of recent and fossil kauri resin. Although agathalene is a far less specific secondary biomarker, it indicates the botanic origin of the fossil resin nodule.
Besides other potential producers of agathic acid, precursors of the present-day conifer species Agathis dammara and A. australis were distributed in a wider palaeophytogeographic range than today and might have been the botanical source of kauri resin. In view of the east-west directed Early Cretaceous surface current system of the Tethys ocean, the palaeogeographic provenance of the Werdenfels resin nodule probably was a mainland positioned further to the east or southeast of the Helvetic shelf, to where it was transported probably by driftwood of the resin-producing Agathis sp.
... These studies provide excellent evidence that resins have the potential to retain their original characteristic isotopic signature. In another study (Murray et al. 1994), carbon isotopic ratios from two resinites washed ashore on the southern coast of Australia were compared to reference samples. Both isotopic and molecular evidence showed that the resinites most closely resemble both fossil and recent dammar from South-East Asia but not Australia. ...
Resin found within Canaanite amphorae from the Late Bronze Age shipwreck discovered off the coast of southwest Turkey at Uluburun has previously been identified as Pistacia sp. Although evidence from Egypt suggests that this resin was in high demand and typically transported in such amphorae, it has also been proposed that the amphorae contained wine, with the resin used to seal the interior surfaces and to flavour and/or preserve the wine. To attempt to resolve this question, we have analysed five samples of pistacia resin found in amphorae from the shipwreck using a range of analytical techniques which have used in the past for the analysis of wine residues: spot tests, FT-IR, and HPLC-MS-MS. As well as the archaeological samples, we have analysed modern samples of pistacia resin, leaves and fruit to determine the effectiveness of each technique and to exclude the possibility of false positive results. In addition to the analyses for wine we also detail analysis (GC-MS) of the terpenoids for the purpose of further molecular characterisation of the resin. Bulk stable isotope analysis was used in comparison with similar resins to attempt to identify the geographical origin of the resin.
The Wenchang B depression and the western Qionghai uplift, in the south of the Zhu-3 sub-basin, are two adjacent sub-tectonic units with multiple oil-bearing structures. The former contains well-developed source rocks, whereas the latter does not. Previous studies have preliminarily explored the source of crude oil in the Wenchang B depression and the western Qionghai uplift. However, systematic investigations have been absent in characterizing the two main source rocks (i.e. Enping and Wenchang formations) and elucidating the migration of crude oil, which has significantly hindered oil and gas exploration. In this study, multiple methods are integrated to re-evaluate the source rocks of the depression, clarify crude oil sources, and analyse vertical oil migration and accumulation characteristics. The methods used included Rock-Eval pyrolysis, carbon isotope analysis, gas chromatography-mass spectrometry (GC-MS), hierarchical cluster analysis (HCA), and basin modelling. The source rocks of the Wenchang formation are demonstrated to have good to excellent hydrocarbon generation potential, whereas those of the Enping Formation have fair to good potential. Both source rocks are further divided into two members (i.e. EP1 and EP2 members for the Enping Formation and WC1 and WC2 members for the Wenchang Formation) based on differences in the biomarkers including ratios of bicadinanes (W + T)/C30hopane (C30H), ∑C30 4-methylsterane (MSt)/∑C29 regular sterane (RSt), pristane (Pr)/phytane (Ph), and ∑C27RSt/∑C29RSt, the source rocks are divided into four sets, named E1, E2 of the Enping Formation, and W1, W2 of the Wenchang Formation, respectively. Both W1 and W2 source rocks were weakly oxidizing-weakly reducing sedimentary environments. The input of organic matter to W2 source rock was dominated by aquatic organisms such as algae. The parent source of W1 source rock has both the contribution of aquatic organisms and the input of terrestrial organic matter. The E1 source rock was formed in an oxidative depositional environment, and its parent source is similar to that of W1. E2 source rock was a weakly oxidizing-weakly reducing depositional environment, and the parent source was resins from higher plants. There are great differences in crude oil characteristics. Through HCA and oil-source correlation analysis, the crude oil in the Wenchang B depression was found to be mainly from the W2 source rock. However, in the northern part of the depression, some crude oil was suggested to originate from both W1 and E1 source rock, presenting mixed characteristics. The crude oil in the western Qionghai uplift was mainly derived from W1 and E1 source rocks, with a small part was from the W2 source rock.
There is a lack of systematic study on geochemical characteristics and the source of crude oil in Shenhu uplift area of the Pearl River Mouth Basin (PRMB). Under such circumstances, the Rock–Eval, gas chromatography (GC), and gas chromatography-mass spectrometry (GC–MS) experiments were carried out. The results show that the following: (1) The medium-deep lacustrine source rocks of the Wenchang Formation (MWC) in the Wenchang-B depression have the highest organic matter abundance. The shallow lacustrine source rocks of the Wenchang Formation (SWC) in Wenchang-B depression and the shallow lacustrine source rocks of the Enping Formation (SEP) in the Wenchang-A depression have relatively low organic matter abundance, but three sets of hydrocarbons have reached the mature stage and have good hydrocarbon generation potential. (2) The n-alkanes of crude oil in the Shenhu uplift have pre-peak characteristics, and the Pr/Ph > 2.00. The tricyclic terpene (TT) content is relatively low, and C19-C20-C21-C23TT presents a “low–high-low” distribution characteristic. Meanwhile, the content of rearranged sesquiterpanes is higher in bicyclic sesquiterpanes. In addition, ααα20RC27-ααα20RC28-ααα20RC29 regular steranes are “L”-shaped, C30-4 methyl sterane (C30-4MSt)/C29 regular sterane values are between 0.24 and 0.34, and dicadinane (W + T)/C30H values are 1.08–1.61. By comparing these biomarkers with source rocks one by one, it is finally found that the crude oil has the closest genetic relationship with the SEP in well WA4.
The Northern Hemisphere dominates our knowledge of Mesozoic and Cenozoic fossilized tree resin (amber) with few findings from the high southern paleolatitudes of Southern Pangea and Southern Gondwana. Here we report new Pangean and Gondwana amber occurrences dating from ~230 to 40 Ma from Australia (Late Triassic and Paleogene of Tasmania; Late Cretaceous Gippsland Basin in Victoria; Paleocene and late middle Eocene of Victoria) and New Zealand (Late Cretaceous Chatham Islands). The Paleogene, richly fossiliferous deposits contain significant and diverse inclusions of arthropods, plants and fungi. These austral discoveries open six new windows to different but crucial intervals of the Mesozoic and early Cenozoic, providing the earliest occurrence(s) of some taxa in the modern fauna and flora giving new insights into the ecology and evolution of polar and subpolar terrestrial ecosystems.
Amber is fossilised plant resin. It can be used to provide insights into the terrestrial conditions at the time the original resin was exuded. Amber research thus can inform many aspects of palaeontology, from the recovery and description of enclosed fossil organisms (biological inclusions) to attempts at reconstruction of past climates and environments. Here we focus on the resin itself, the conditions under which it may have been exuded, and its potential path to fossilisation, rather than on enclosed fossils. It is noteworthy that not all plants produce resin, and that not all resins can (nor do) become amber. Given the recent upsurge in the number of amber deposits described, it is time to re‐examine ambers from a botanical perspective. Here we summarise the state of knowledge about resin production in modern ecosystems, and review the biological and ecological aspects of resin production in plants. We also present new observations on conifer‐derived resin exudation, with a particular focus on araucarian conifer trees. We suggest that besides disease, insect attacks and traumatic wounding from fires and storms, other factors such as tree architecture and local soil conditions are significant in creating and preserving resin outpourings. We also examine the transformation of resin into amber (maturation), focusing on geological aspects of amber deposit formation and preservation. We present new evidence that expands previous understanding of amber deposit formation. Specific geological conditions such as anoxic burial are essential in the creation of amber from resin deposits. We show that in the past, the production of large amounts of resin could have been linked to global climate changes and environmental disruption. We then highlight where the gaps in our knowledge still remain and potential future research directions.
Some higher plants, both angiosperms and gymnosperms, can produce resins and some of these resins can polymerize and fossilize to form ambers. Various physical and chemical techniques have been used to identify and profile different plant resins and have then been applied to fossilized resins (ambers), to try to detect their parent plant affinities and understand the process of polymerization, with varying levels of success. Here we focus on resins produced from today's most resinous conifer family, the Araucariaceae, which are thought to be the parent plants of some of the Southern Hemisphere's fossil resin deposits. Fourier transform infrared (FTIR) spectra of the resins of closely related Araucariaceae species were examined to test whether they could be distinguished at genus and species level and whether the results could then be used to infer the parent plant of a New Zealand amber. The resin FTIR spectra are distinguishable from each other, and the three Araucaria species sampled produced similar FTIR spectra, to which Wollemia resin is most similar. Interspecific variability of the FTIR spectra is greatest in the three Agathis species tested. The New Zealand amber sample is similar in key shared features with the resin samples, but it does differ from the extant resin samples in key distinguishing features, nonetheless it is most similar to the resin of Agathis australis in this dataset. However on comparison with previously published FTIR spectra of similar aged amber and older (Eocene) resinites both found in coals from New Zealand and fresh Agathis australis resin, our amber has some features that imply a relatively immature resin, which was not expected from an amber of the Miocene age.
A new Turonian amber occurrence, representing the oldest in situ amber locality in Australia and the southern-most locality in Gondwana, has recently been discovered in the Otway Basin of Victoria. The amber was collected from petroleum cores and many pieces contain a range of inclusions that can provide information on the depositional history of the resin. To date, one species of fern spore (Cyathidites minor) and one species of lycophyte spore (Kraeuselisporites sp?) have been conclusively identified in the amber, along with filamentous microorganisms and degraded plant matter. Several samples are also rife with pseudoinclusions as reported recently in other ambers. The abundance of preserved particulate debris and wind dispersed spores suggest that the Otway amber formed subaerially. Furthermore, based on the range of bioinclusions and forms of pseudoinclusions preserved within a single piece of amber, the locus of hardening for individual samples is variably interpreted as occurring in the tree tops, on the tree trunk or on the ground surface. Notably, specific inclusion assemblages are associated with certain colours of amber. By extension, and in accordance with recent studies, amber colour may be indicative of depositional environment. Variation in the environment of solidification may, therefore, be sufficient to account for the broad range of morphological characteristics preserved in a single amber deposit.
Three C26 tetracyclic terpanes were detected in the saturated hydrocarbon fractions of oil sand samples especially rich in bicadinanes W, T and R from the Oligocene Huizhou Formation in the XW-1 well in the Haitoubei–Maichen Sag of the Beibuwan Basin. Their mass spectra show molecular ions of the three tetracyclic terpanes at m/z 358, and their key fragment ions at m/z 343 (M+-15) and m/z 315 due to loss of an isopropyl group. These characteristics are very similar to that of C30cis–cis–trans (W) and trans–trans–trans (T) bicadinanes. In addition, the relative abundances of the C26 tetracyclic terpanes show an excellent positive correlation with the C30 bicadinanes W and T in 27 oil sand samples. Therefore, the three C26 tetracyclic terpanes are tentatively identified as degraded bicadinanes, which like bicadinanes, may indicate input from dammar resins and can be used to discriminate the origin of crude oils.
Surface water samples were collected with Niskin bottles on the Amazon continental shelf during peak river discharge. A suite of sesquiterpenoid compounds, mainly cadinane types, are present in the hydrocarbon fractions in trace amounts (ppb level) as dominant neutral components with abundances much higher than other compounds (e.g., n-alkanes). In general, the sesquiterpenoids found can be divided into four major groups: hydroxylated compounds, a series of saturated and unsaturated bicyclanes, mono-, and di-aromatic hydrocarbons. In samples closer to the river mouth the co-occurrence of cadalene together with its possible precursors (e.g. cadinols and cadinenes) as well as intermediates (e.g. α-calacorene, calamenene) is more notable. As distance from the river mouth increases the co-occurrence becomes less notable, indicating the degradation of these biogenic compounds during their transport seaward. Moreover, the absence of the ring B mono-aromatic component (5,6,7,8-tetrahydrocadalene) and its analogs with one double bond in ring A provides evidence that the early degradation of sesquiterpenoids starts with aromatization of ring A.
Biomarker and n-alkane isotope profiles have been measured for 29 Late Cretaceous/Tertiary oils from SE Asia, China, Papua New Guinea, New Zealand and the U.S.A. The results are interpreted with respect to six kinds of source rock depositional setting: fluvio-deltaic (FD), freshwater transitional (TR), lacustrine (LAC), saline lacustrine (SAL), marine deltaic (MD) and marine carbonate (MC). A comparison of biomarker and n-alkane isotope results suggests that parameters such as the oleanane/hopane ratio may overestimate the higher plant contribution to marine oils. The abundance of bicadinanes is much more variable than that of oleanane, probably because of a specific association with the highly resinous, dipterocarp hardwoods of SE Asia. However, traces do occur in an oil from outside the paleogeographic range of the dipterocarp family, confirming that there is also a more general angiosperm source. The bicadinane isomeric distribution is shown to depend on maturity, leading to new maturity parameters which are resistant to even very heavy biodegradation. Retention indices based on the regular hopane series are provided for the main bicadinane and methyl bicadinane isomers and for a group of oleanane-related triterpanes of unknown structure. The presence of the latter compounds may indicate locally deposited as opposed to transported higher plant matter in the source. Source rock depositional setting is the primary control on the shape of the n-alkane isotope profile, with negatively sloping curves being characteristic of FD and TR oils and flat or positively sloping curves typical of marine oils. The difference is probably related to the bacterial reworking of higher plant matter in the FD environment. A slight isotopic anomaly at n-C17 correlates with the abundance of algal-derived steranes and may indicate a minor marine contribution to the source of an FD oil.
Bitumens stranding along the coastlines of the Northern Territory, Western Australia, South Australia, Victoria and Tasmania often have biomarker signatures which closely match those of oils of S.E. Asian origin. A suite of these bitumens was studied to determine the isotopic signatures of their alkanes and to compare them to similar oils from the Central Sumatra Basin. Saturated hydrocarbons were separated into a fraction containing n-alkanes and isoalkanes and one containing the multibranched/cyclic components using adduction into silicalite. Gas chromatography-isotope ratio mass spectrometry (GC-IRMS) of the n-alkanes revealed δ13C signatures covering a wide range of values from −25.5‰ to −29‰ PDB but generally falling between those of the botryococcane-containing Minas and Duri oils from the Central Sumatra Basin. n-Alkanes of the Minas oil are 3–4‰ lighter than their Duri counterparts. The isotopic compositions of pristane and phytane cover a similar range, δ13C = −24‰ to −27‰. Botryococcane is consistently heavy with δ13C values in the range −11 to −14‰. One bitumen sample with no botryococcane but abundant bicadinanes showed n-alkane δ13C values in the range −28 to −29‰, at the light extreme for waxy bitumens in our sample suite. Sample to sample differences in carbon isotopic signatures of n-alkanes are attributed mainly to variations in primary source, with weathering and biodegradation as minor causes. Instances of low precision for replicate analyses (± 2‰) are caused by the relative abundance of co-eluting isoalkanes. Overall, the isotopic patterns of waxy bitumens from the Australian coastline provide independent confirmation of their similarity to Central Sumatran lacustrine oils. On the other hand, asphaltic bitumens from the southern Australian coastline are isotopically light with n-alkane δ13C values in the range −31.5 to −33‰. This distinctive feature may assist identification of their source.
Research on the chemical composition of fossil resins has evolved during the last decades as a multidisciplinary field and is strongly oriented toward the correlation with their geological and botanical origin. Various extraction procedures and chromatographic techniques have been used together for identifying the volatile compounds contained in the fossil resin matrix. Hyphenation between thermal desorption (TD), gas chromatography (GC) and mass spectrometry detection (MS) has been chosen to investigate the volatile compounds fraction from ambers with a focus on Romanite (Romanian amber) and Baltic amber species. A data analysis procedure was developed for the main purpose of fingerprinting ambers based on the MS identity of the peaks generated by the volatile fraction, together with their relative percentual area within the chromatogram. Chromatographic data analysis was based entirely on Automated Mass Spectral Deconvolution &Identification System (AMDIS) software to produce deconvoluted mass spectra which were used to build-up a mixed mass spectra and relative retention scale library. Multivariate data analysis was further applied on AMDIS results with successful discrimination between Romanite and Baltic ambers. A special trial was conducted to generate pyrolysis "like" macromolecular structure breakdown to volatile compounds by gamma irradiation with a high absorbed dose of 500 kGy. Contrary to our expectations the volatile fraction fingerprints were not modified after irradiation experiments. A complementary non-destructive new approach by ESR spectroscopy was also proposed for discriminating between Romanite and Baltic ambers.
Bicadinanes (C30 pentacyclic triterpanes) have only been reported in crude oils and sediment extracts from S.E. Asia. The present investigation indicates that they are also widely present in land plant-derived Tertiary oils from the Surma Basin of N.E. Bangladesh. Oleanane is also abundant in these oils though its distribution does not correlate with those of the bicadinanes. This is consistent with separate specific land plant sources for these two classes of triterpanes, and with the formation of bicadinanes during maturation of polymerised angiosperm tree resin.
Detailed geochemical analysis of eleven Australian coastal bitumens - eight from ocean beaches in South Australia and western Victoria, and three from stranding sites on Bathurst Island and Cobourg Peninsula in the Northern Territory - shows that they are inspissated waxy crudes of low API gravity and low sulphur content.Only one bitumen appears not to be a natural crude, its composition is that of a weathered fuel oil. The rest may be divided into two types, as follows:Bitumens from Ocean Beach, Geltwood Beach and Sleaford Bay in South Australia are paraffinic to naphthenic in composition. Those from the Northern Territory, Victoria and Cape Northumberland, SA, together with a second sample from Geltwood Beach, are highly paraffinic to paraffinic. Both types of bitumen strand at Geltwood Beach where each contains appreciably more nickel (85-105 ppm) than bitumens of either type found elsewhere (3-30 ppm).The effects of exposure are more evident in some bitumens than in others. Weathering has involved evaporative loss of volatile components, bacterial degradation of n-alkanes up to C25, and an increase in asphaltenes at the expense of saturated hydrocarbons.A high proportion of long-chain (C23+) n-alkanes in the stranded crudes indicates that they are products of the diagenesis of mostly continental vegetation. However, their low pristane/phytane ratios (The geochemistry of the bitumens supports the belief that they represent natural submarine seepages. The amount of weathering sustained by the bitumens in each suite correlates with their exposure time. Their degree of alteration, in conjunction with a knowledge of local surface currents, can be used to establish their provenance. Cretaceous freshwater and paralic sediments are present at depth offshore in both the western Otway Basin and the Money Shoal Basin. These sediments constitute the most likely ultimate source for the immature oils that gave rise to the coastal bitumens now found scattered along the southern and northern coastlines of Australia.
Tetracyclic diterpene hydrocarbons containing the kaurane, phulocladane (13β-kaurane), and beyerane skeletons have been identified in some Australian petroleums and sediment extracts; these compounds are useful biological markers for higher plants.
The Leeuwin Current is a surface stream of warm, low-salinity tropical water that flows poleward (southward), against the climatological mean equatorward winds, from northwestern Australia to Cape Leeuwin and then eastward towards the Great Australian Bight. It flows principally, but not exclusively, in autumn and winter. In the north, it is broad and shallow (200 km by 50 m), tapering and deepening in the south to a relatively narrow current (less than 100 km wide), with a top speed of 1.8 ms−1 and strong vertical and horizontal shears. There is an equatorward undercurrent below. The warm, low-salinity Leeuwin Current water intrudes between the continent and the southgoing high-salinity flow described by Andrews (1977). As the current approaches Cape Leeuwin, it extends down to about 200 m and is most commonly centered at the shelf edge. After rounding Cape Leeuwin, it spreads onto the shelf and develops seaward offshoots that result in cyclone/anticyclone eddy pairs. A strong poleward geopotential gradient is thought to drive the Leeuwin Current.
The genus Agathis, a group of conifers found in the land areas between New Zealand and Malaysia, has several conspicuous resin-forming systems. Thus, the New Zealand species Agathis australis (Salisbury) produces resins, often in very large amount, in the heartwood, in resin canals in the bark, in resin canals in the leaves, in the leaf surface layers, and elsewhere. These resins are all different and are mostly quite complex mixtures.
Diterpanes occur widely in the resins of modern conifers, suggesting that sedimentary diterpanes are chemical markers for fossil resins, particularly those derived from conifers. In this paper, the use of the relative abundance of these chemical fossils for establishing genetic relationships between the organic matter in sediments and crude oils has been demonstrated using sediments and crude oils from the Gippsland Basin.The crude oils were characterised by their remarkably uniform distributions of diterpanes and similar relative amounts of diterpanes and hopanes. In contrast, the sediments showed much greater variability, with only one sediment horizon, an organic-rich shale, showing the same properties as the crude oils.
Whether or not the sediments in the Eromanga Basin have generated petroleum is a problem of considerable commercial importance which remains contentious as it has not yet been resolved unequivocally. Sediments of the underlying Cooper Basin were deposited throughout the Permian and much of the Triassic, and deposition in the overlying Eromanga Basin commenced in the Early Jurassic and extended into the Cretaceous. As Araucariaceae (trees of the kauri pine group) assumed prominence for the first time in the Early to Middle Jurassic and were all but absent in older sediments, a promising approach would seem to be using the presence or absence of specific araucariacean chemical marker signatures as a means of distinguishing oils formed from source rocks in the Eromanga Basin from those derived from the underlying Cooper Basin sediments.The saturated and aromatic hydrocarbon compositions of the sediment extracts from the Cooper and Eromanga Basins have been examined to identify the distinctive fossil hydrocarbon markers derived from such resins. Sediments from the Eromanga Basin, which contain abundant micro-fossil remains of the araucariacean plants, contain diterpane hydrocarbons and aromatic hydrocarbons which bear a strong relationship to natural products in modern members of the Araucariaceae. Sediments from the Permo-Triassic Cooper Basin, which predate the Jurassic araucariacean flora, have different distributions of diterpane biomarkers and aromatic hydrocarbons.Many oils found in the Cooper/Eromanga region do not have the biological marker signatures of the Jurassic sediments and appear to be derived from the underlying Permian sediments; however, several oils contained in Jurassic to Cretaceous reservoirs show the araucariacean signature of the associated Jurassic to Early Cretaceous source rock sediments. It is likely, therefore, that these oils were sourced and reservoired within the Eromanga Basin and have not migrated from the Cooper Basin sequences below. Accordingly, exploration strategies in the Cooper Eromanga system should include prospects that could have been charged with oil from mature Jurassic/Early Cretaceous sediments of the Eromanga Basin.
This review article focuses on terpenoid resins, beginning by describing their chemistry, occurrence in plant genera such as Pinus, Agathis, Hymenaea and Copaifera, and the discovery of their role in repelling or attracting insects. It then deals with where and when in geological history the fossilized resin, or amber, formed; the environments in which resin is mostly produced; and theories and examples of the ecological role of plant resins. Examples of amber sources from the late Carboniferous to Pleistocene are given, with a table of locations and ages for which botanical sources have been studied. Deposits indicate that copious production of terpenoid resins has always occurred in tropical and subtropical environments, and reasons for its occurrence at different times is linked to climatic conditions and tectonics. There is growing evidence that production and compositional variation of resin may be a protection against phytophagous insects and pathogenic fungi. -J.W.Cooper
The distributional patterns of inshore marine faunas of southern South America, southern Africa and southern Western Australia are related to the effects of the cold northward flowing Humboldt and Benguela Currents and warm southward flowing Leeuwin Current respectively. The extent and nature of zoogeographic provinces, their faunal affinities and levels of endemicity are reviewed. In South America and southern Africa, cold temperate provinces resulting from the effects of the cold currents and associated upwellings act as barriers to dispersal of warm water faunas especially along the SW coasts. A corresponding cold temperate province is absent from SW Australia and warm water species are distributed farther south than in South America and Africa. -Authors
This review has summarized some recent important developments in stable carbon and hydrogen isotope studies, as applied to hydrocarbon and fossil fuel research. Stable isotope concentrations in erogens and coals are independent of the stage of their thermal evolution and are hence conservative properties which remain unchanged during oil formation. Primary isotope variations in kerogens and coals are independent of the type of kerogen or coal, and little is known on the causes of variations. In natural gases, stable isotope concentrations in methane are controlled by the process of gas formation. Using molecular and isotopic compositions allows genetic characterization of natural gases. Application of combined carbon and hydrogen isotope analyses in methane facilitates elucidation of any complex origins of gases.
Oil, gas and condensate have been recovered from the Upper Cretaceous/Tertiary as well as older rocks in a number of wells in the Beaufort-Mackenzie Basin. In order to assist in the quantitative evaluation of the petroleum potential and to assist in developing an overall geological model of this basin, a geochemical study was undertaken to identify the occurrence and distribution of specific, potential petroleum source rocks within the Post-Boundary Creek/Smoking Hills Upper Cretaceous/Tertiary fluviodeltaic sediments.
A tropical element in the demersal and pelagic fauna of the Great Australian Bight has been observed. The fauna includes benthic invertebrates, such as the basket star, Euryale aspera (Lamark), and the holothurians Pentacta anceps (Selenka) and Pentacta quadranguiaris (Lesson), and tropical pelagic tuna, such as the oriental bonito, Sarda orientalis (Temminck and Schlegal). It is suggested that the Leeuwin Current, which flows southward to Cape Leeuwin and then eastward, is responsible for the existence of tropical fauna in the Bight. The low salinity waters of the Leeuwin Current were observed for the first time to round Cape Leeuwin.
From the fresh leaves of polypodium someyae eupha-7, 24-diene and from the fresh rhizomes of P. fauriei (20R)-dammara-13 (17), 24-diene were obtained and characterized. These hydrocarbons are the first derivation from a natural source. They are rather unstable in the air.
The foliage shoots, male cones, and female cone-scales of a new Tertiary species of Araucaria, section Eutacta, from the brown coal at Yallourn, Victoria, have been described; leaves and male and female cones possessing the general features that characterize species of Agathis have been identified. Leaves of a second species of Agathis have been distinguished in a bed associated with the brown coal at Bacchus Marsh, near Melbourne, Vic.
The Oligocene Talang Akar formation is the major source for petroleum (oil and gas) in the Ardjuna sub-basin. Source rock quality varies within the deltaic to marginal marine complex, with coals deposited on the lower delta plain being distinctly oil-prone, whereas the surrounding delta plain shales are largely gas prone. Shales and “drifted” coals laid down in marine-influenced interdistributary bay environments show increasingly oil-prone characteristics, possibly due to preferential transport of hydrogen-rich plant components to more distal setting. Molecular characteristics of the coals and shales are similar, with higher plant (angiosperm) biomarkers and their aromatic derivatives occuring widely. Kinetic studies of hydrocarbon generation, and stimulated maturation experiments using hydrous pyrolysis, indicate that the delta plain coals are the major source for crude oils in the basin, with a secondary, but minor contribution from marine-influenced interdistributary bay shales. Delta plain shales are interpreted to expel gaseous products only. The stratigraphic and spatial location of oil and gas fields were examined with respect to their position relative to oil and gas generating source rocks. The field distribution could not be explained in terms of source rock geochemistry alone, and phase behavior of petroleum during secondary migration was shown to exert an important influence on the distribution of oil and gas deposits in the basin.
Samples of weathered bitumens were collected from granite rocks and quartz-sand beaches near the high-water mark along the west and south coasts of Western Australia. Samples were subjected to analysis using GC and GC-MS techniques. The proportions of n-alkanes and branched and cyclic compounds in the samples were variable and the variation was attributed to differences in sample weathering. More detailed analysis of the bitumens for biomarkers revealed the presence of botryococcane, 4-methylsteranes, bicadinanes and oleanane. The occurrence of these compounds has also been observed in crude oils from the S.E. Asian region. The presence of bicadinanes has been attributed to a source contribution from an angiosperm currently confined to tropical regions and indicates that the source rocks from which the bitumens were derived were deposited after Late Cretaceous times. The absence of Late Cretaceous and Tertiary sediments deposited in lower latitudes in the northwest and western offshore basins of Australia suggests a non-local source of the bitumens. A mechanism involving the Leeuwin Current has been proposed to account for transport of these bitumens which are presumably sourced from locations in S.E. Asia.
Hydrous pyrolysis experiments are useful in evaluating the composition, yield, and kinetics of liquid hydrocarbons generated from potential source rocks. Using this technique on a representative set of resinites revealed that fossil resin does not generate a light naphthenic crude oil. Gas chromatograms of liquid hydrocarbons generated by resinites are dominated by aromatic peaks and show no resemblance to commercially produced crude oils. Resinites may make minor contributions to conventionally sourced crude oils, but their limited occurrence inhibits their potential as a prolific source of petroleum on a basinal scale. Data from the natural system and pyrolysis experiments also indicate that resinites do not generate liquid hydrocarbons at abnormally low levels of thermal maturity. 12 figs., 2 tabs.
Information relevant to the ecology of Agathis australis is presented, together with a distribution map based on its presence or absence in grid squares and bibliographic references to other information.
Series of structurally related hydrocarbons consisting of one or more sesquiterpane units with a l,6-dimethyl-4-(1-methylethyl)naphthalene (cadalene) carbon skeleton are shown to be present in the saturated and aromatic hydrocarbon fractions of crude oils from southeast Asia. These hydrocarbons are thought to originate from a cadinene polymer present in dammar resins, which depolymerises upon thermal stress leading to the formation of cadinanes, muurolanes, di- and bicadinanes, tricadinanes, and similar aromatic compounds. Homologues with an additional methyl group were also encountered. Identification of compounds was largely based on interpretation of mass spectral data. A diagenetic pathway relating the polycadinene occurring in extant resins with these polycyclic hydrocarbons is proposed, emphasizing their biomarker potential.
By the use of column and reversed-phase paper chromatography a thorough analysis of dammar resin has been made. The "β-resene" has been shown to be a polymeric material, while the remainder of the resin is principally a complex mixture of neutral and acidic triterpenes, some of which have been isolated and partly characterised. The main neutral triterpenes are: dammadienone, C30H48O; dammadienol C30H 50O; two isomeric hydroxydammarenones, C30H 50O2, and their related diols, C30H 52O2; and a third ketol, hydroxyhopanone, C 30H50O2. In addition to dammarolic acid, previously described, three further acids have been isolated one of which has been shown to be ursonic acid: the other two are dammarenolic acid, C 30H50O3, and dammarenonic acid, the latter obtained only in small yield as its methyl ester, C31H 50O3.
A diverse biota including vertebrates, invertebrates, and plants is known from the Early Cretaceous of southeastern Australia. It is preserved in sediments that accumulated in the rift valley formed as Australia began to separate from Antarctica. As there was no significant terrestrial barrier between the two continents at the time, it is likely that the Early Cretaceous biota of the nearest region of East Antarctica may have been quite similar to that of southeastern Australia. Dominant among the vertebrates are turtles and at least four hypsilophodontid dinosaur species. Three species of theropods, including Allosaurus sp., are the only other dinosaurs represented. Other tetrapods include a few scant traces of plesiosaurs, pterosaurs, a lizard, and a labyrinthodont amphibian. Southeastern Australia was located well inside the Antarctic Circle of the day. Oxygen isotope studies suggest mean annual temperatures for the area between -5 and 8°C. These low temperatures are concordant with the character of both the flora and invertebrate fauna. The presence of juvenile hypsilophodontids implies that these animals were breeding in the area. The large eyes and optic lobes of the brain of these dinosaurs relative to other ornithopods suggests they may have been adapted for active behaviour under low light conditions.
Three major water masses occur for all or part of the year within the shelf and slope region off southern Australia. A Leeuwin Current carries the warmest water mass of relatively low salinity into the region, principally along the shelf break as far east as 130ºE. This water mass first enters the western end of the region in May, disappears from the eastern end after July and from the western end by September-October. A warm and very high salinity water mass is present in the central and eastern half of the Great Australian Bight for most of the year. This central Bight water mass drifts to the south-east and occupies much of the shelf and slope region east of 135ºE., particularly in winter. A West Wind Drift cold water mass of lowest salinity is found throughout the year off the slope region of southern Australia and periodically intrudes into the shelf break, especially when the Leeuwin Current is weakly developed. The central Bight waters, which provide a second source of warm waters in the eastern half of the region, greatly complicate the interpretation from satellite imagery of warm waters in that region as being derived solely from the Leeuwin Current. Adequate salinity data and sea surface temperatures derived from satellite imagery are required to determine more accurately the eastward extent of the Leeuwin Current.
A pair of isomeric dammarenes has been identified in numerous Pleistocene to Jurassic sediment samples, most of them from continental margins. Their structures have been determined to be (20 R )- and (20 S )-dammar-13(17)-ene based on comparison of mass spectra and Chromatographic data with those of synthetic standards. Their saturated counterparts have also been found in a few samples. Based on rigorous nuclear magnetic resonance (NMR) studies with one synthetic standard and molecular mechanics calculations, it is suggested that geologically occurring dammaranes possess 13 ,17 (H) stereochemistry. Compounds with a dammarane skeleton are well known natural products of several families of land plants, but the widespread occurrence of dammarenes in marine sediments suggests an alternative origin, supported by their carbon isotopic signature. Dammarenes can be envisaged as direct proton-induced cyclisation products from squalene and may represent a contribution from microorganisms. Although we are in favour of this hypothesis, an origin from geologically induced rearrangements of other compounds cannot, at present, be excluded.
Analyses of two Tertiary fossil resins and a Tertiary montan wax have revealed the presence of a number of sesquiterpenoids. Using gas chromatographic retention data obtained on both polar and non-polar stationary phases and mass spectral comparisons with authentic compounds, the sesquiterpenoids α-cedrene, cedrane, cuparene, cedren-10-one, 8βH cedran-9-one and cuparenic acid have been identified in the fossil resin retinellite and a montain wax (both Oligocene) from lignite beds in the Bovey basin of Devon, England, and in the Pliocene fossil resin ionite from the lone valley of California. U.S.A.The sesquiterpenoids α-cedrene, cuparene and cuparenic acid are characteristic constituents of the essential oils of the Cupressaceae, a family of trees and shrubs of the order Coniferales, and it is argued that these fossil resins, and the montan wax, were derived from older forms of this family of plants. The ketones cedren-10-one and 8βH cedran-9-one, and the saturated hydrocarbon cedrane, are not reported to be constituents of modern genera of Cupressaceae and may have been formed during diagenesis. The cedrane occurring in these deposits appears to be a chemical hydrogenation product of α-cedrene. The ketones, on the other hand, may have resulted from the oxidation of α-cedrene although the mechanism of these reactions is not clear. If the ketones are not undetected constituents of these plants, then the presence in these deposits of both oxidised and fully-reduced α-cedrene products infers that separate phases of oxidation and reduction occurred during the diagenesis of the fossil resins and the montan wax.
The structure of a fossil resin from Miocene coal outcrops of the Bukit Asam region (Sumatra) has been studied. The fossil material has been formed from sesqui- and tri-terpenes from trees of the Dipterocarp family. The original terpenes have lost virtually all oxygen-containing functions and the resulting mono- and di-olefins have polymerized to a mainly non-crosslinked resin whose components have molecular weights of up to 300,000.
The extracts of Middle Miocene sediment samples from the Yacheng gasfield offshore Hainan Island, China contain high amounts of compounds that originate from polycadinene. This polymer is present in the dammar resins produced by angiosperm trees such as the Dipterocarpaceae and disintegrates upon thermal stress. The fragments can react intramolecularly to form relatively stable compounds which are subsequently hydrogenated or dehydrogenated. Many saturated and aromatic compounds formed in this way are encountered in the sediment extracts. The presence of bi- and tricadinanes was established by gas chromatography-mass spectrometry. The occurrence of tetra- and possibly pentacadinanes was suggested by high temperature-gas chromatography.
Eleven samples of resinite and resinite-rich coals and shales were characterized by organic petrography. Rock-Eval pyrolysis, i.r. spectroscopy, gas chromatography, GC-MS and pyrolysis-gas chromatography. Resinites tentatively classified as types A and B have yellow fluorescence, high hydogen indices, relatively low Tmax values and saturated hydrocarbon fractions of extracts and pyrolysates which are rich in terpenoids and terpenoid-derived aromatics. Resinites A are found as fracture fills and may be an intermediate product between plant resins and materials of more kerogenous nature. The type B resinites are identified by their discrete, usually oval shape. Another type of resinites has brown fluorescence, somewhat lower hydrogen indices, higher Rm and Tmax values and saturated hydrocarbon fractions of extracts which are rich in normal alkanes, and pyrolysates which are rich in normal alkanes/alkenes. There is a possibility that some of the differences observed between the yellow and brown fluorescent resinites are really part of a continuum and that these differences are a function of maturity. Further sampling and research may clear up this question. If maturity is the controlling agent in the differences observed, then mobile materials (mainly terpenoids) are generated from resinites at a very low maturation level (0.3% Rm) and hydrocarbon potential for all resinites should be exhausted at a maturity level of 0.8% Rm.
The triterpene fraction ( ∼ 80%) of the oleoresin from Dipterocarpus pilosus has been found to contain dipterocarpol and several known (dammara-20,24-dien-3-one, dammara-24-ene-3,20-diol, ocotillone-II, ocotillol-II) and new triterpenes related to this. Structure elucidation of two of these new triterpenes viz hollongdione and dipterocarpolic acid, is discussed. The resin also contains significant quantities of asiatic acid and two of its acetyl derivatives and 2α-hydroxyursolic acid.
The chemical composition of a fossil resin from a Miocene outcrop in Brunei, South East Asia, is compared with its extant counterpart dammar, obtained from trees of the family Dipterocarpaceae, to establish the nature of the precursor of bicadinanes. The alcohol soluble fractions of the resins consist of functionalized triterpenoids and a small amount of sesquiterpenoids. None of the compounds present in this fraction bears any structural relation to bicadinanes. The alcohol insoluble fractions of the resins consist of a polymer based on cadinene. A structure for this polymer is proposed. Heating the polymer in dammar resin resulted in the formation of monomeric, dimeric, and trimeric cadinenes. It is thought that the naturally occurring bicadinanes result from dimeric cadinenes upon cyclization.
Ekweozor et al. [Chem. Geol. 27, 11-28 and 29-37] first discovered an unknown compound with a GC retention time very close to that of the 18α (H) olenane peak, in oils and Tertiary sediments of the Nigerian Delta. This compound was called "J". Several authors [Wang et al., Advances in Organic Geochemistry 1981, pp.108-113, Wiley Chichester (1983); Schoelle et al., ibid., pp. 156-163] reported the occurrence of 18α(H)oleanane without underlying the presence of "J", because of their coelution. In this study, the presence of "J" has been confirmed in more than 150 rock-extracts and 19 oils from different countries, and is identified as the 18β(H)oleanane by comparison to retention time and mass spectrum and by its coelution with an authentic standard. Apart from Tertiary sediments, the 18α(H) and 18β(H)oleananes, have also been found in Upper Cretaceous sediments, which extends the occurrence of these compounds back in age. A maturity correlation has been found between the relative concentration of 18α(H)oleanane and 18β(H)oleanane; in fact, an increase in the 18α(H)/18β(H)oleanane ratio has been observed with increasing depth in several wells. The 18α(H)/18β(H)oleanane ratio has been correlated with other classical maturity parameters, i.e. Ts/Tm, Ro and Tmax.
Cis-cis-trans-bicadinane, an uncommon triterpane present in South East Asian crude oils has been isolated and its structure has been revealed with NMR-spectroscopic methods.
Dammars produced by Dipterocarpaceae growing in Southeast Asia are partly composed of a macromolecule with a polycadinene structure. This polymer is the precursor of many specific compounds encountered in crude oils and sediment extracts from South Asia. Until recently there was no evidence for a more widespread geographical occurrence of this resinous polymer. Using different pyrolysis methods it is shown that the polymers present in a resinite from Utah, USA, and in resins contained in resin canals of Eocene fossil fruits from Germany and England are also polycadinenes. The fossil fruits were undoubtedly produced by ancient representatives of mastixioid Cornaceae, a group of plants which was widespread in the Tertiary of Europe and North America and which is not related to Dipterocarpaceae. These findings extend the known occurrence and origin of the sesquiterpenoid type resin polymer. It is to be expected that catagenetic products of these resin polymers should be present in oils, coals, and sediment extracts from areas outside Southeast Asia.
The high-molecular-weight fractions in fossilized and extant dammar resins were studied using three different pyrolysis methods: flash pyrolysis, open system isothermal furnace pyrolysis and closed system isothermal pyrolysis. The pyrolysates obtained by the first two methods were virtually identical. The composition of the pyrolysates obtained by the third method were dominated by secondary reaction products and resembled naturally occurring crude oils which are partly derived from fossil dammar resins. The pyrolysis results from the three methods were complementary and yielded structural information about the high molecular-weight fraction. It is proposed that this fraction consists of a linear polymeric cadinene.