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Invertebrate fossils found in cave sediments as proxies for Pliocene/Pleistocene paleoenvironment
Abstract
Five samples of clastic sediments from interior cave facies taken in three Slovenian relic caves (Trhlovca, Račiška pečina, and a cave iň Crnotiče Quarry, Classical Karst, SW Slovenia) provided invertebrate fossil remains. Most of them belong to Oribatida but sparse individuals of Cladocera and insects were also identified. They represent the first pre-Quaternary invertebrate fossils found in sediments of continental temperate climate. The Pliocene/Pleistocene age of the sediments was determined by paleomagnetic dating chronologically calibrated by micro-mammal biostratigraphy. Invertebrate fossils could be validated as new proxy for the study of cave sediments due to their suitability for ecological and paleogeographic correlations in caves and outside the caves. They also bring additional information about cave formation and karst hydraulic regime in the area. Although the number of remains was very low, it is evidence that climatic conditions in caves allow a better preservation of fossil remains of some groups as compared to most of the surface habitats. This may open a new direction in the study of cave sediments.
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The aim of this book is to set out the results of common Slovene-Czech researches during10 years when karst superficial and cave sediments grouped according to age and depositional environment in various geographical and geological regions of Slovenia were intensively researched mostly by different palaeomagnetic methods. Palaeomagnetic sediment researches have brought surprising results related to the age of sediments both on the surface and underground and consequently also the first detailed information about the age of caves and indirectly the age of our karst. By comparing these data the time of sedimentation is obtained. At sampling the sediments for palaeomagnetic analyses we found in some cases the fossil remains of fauna; these findings are very important as they allow setting out the palaeomagnetic and magnetostratigraphic analyses into precisely defined time. The introductory part describes the problem of cave sediments dating and their importance at explaining speleogenesis and karst genesis. This part is followed by a detailed presentation of the bases of palaeomagnetic method and magnetostratigraphy in particular related to way of sampling loose sediments and flowstone. In the flowstone the magnetic record is very weak as it contains a tiny bit of iron only; the devices in the laboratory were adapted to measure weak magnetization. A large part follows containing 21 locations, 19 in Slovenia and two on the other side of the border in Italian Karst where various sediments were analyzed by palaeomagnetic methods. Each location is placed in space describing geological, karstological and speleological properties. A precise description of studied sediment profile with lithological and mineralogical composition follows obtained by various research methods. Every profile contains also the palaeomagnetic results with magnetostratigraphic and palaeomagnetic properties. There, where fossils were found they are paleontologically defined. The description of results is followed by interpretation and discussion about the age of sediments. An important part of this book treats the significance of performed researches for the development of the dating method. Palaeomagnetic dating method is comparative, meaning that for definition of absolute sediment age we need additional data provided by other methods. The problems occurring when analyzing the sediments in karst caves due to their specificity are described as well as technical solutions of problems. A survey of achieved dating is added as well as their importance to understand the development of caves and karst in Slovenia, for development of surface and for time definition of known tectonic events. The book is interesting for scientists and experts dealing with karstology, speleology, quartarology, paleontology, geomorphology and geophysics who are engaged in palaeomagnetic dating methods and magnetostratigraphy. This book offers new comprehension from all the mentioned research topics important both for Slovenia (understanding of its geological history, surface development and age of karst) and the international scientific sphere; with the concrete results the book is an important contribution to the science of karstology, geology, geophysics and structural geology.
V kamnolomu Črnotiče je bila izkopana s sedimenti in sigo z zapolnjena jama. Analiziran je bil 1,75 m visok del zapolnitve. Profil je sestavljen iz pasovite karbonatne kamnine z interkalacijami rdečih ilovic. Te so se odložile na erozijsko/korozijsko površino starejše, že močno prekristaljene sige. Pasovita in laminirana karbonatna kamnina profila je sestavljena iz prekristaljenega kalcilutita ter je podobna sladkovodnemu apnencu. Značilna laminiranost nakazuje nastanek iz bogatih organskih filmov. Rdeče ilovice sestavljajo kremen, smektit, vermikulit, gibbsit, pM kaolinit, goethit, atanas, rutil, haematit, kalcit, sljude in glinenec. Vsebujejo tudi pelete z več Mn hidroksioksidov. Rdeče ilovice so ostanki preperevanja, odloženi v z vodo zasičenem okolju. Za v profilu vzete vzorce so značilne srednje do visoke vrednosti Jn kar je posledica velike količine železovih mineralov. Srednja paleomagnetna smer je za skupino normalnih paleomagnetnih polaritet enaka D = 10.6°; I = 55.0°, za skupino reverznih polaritet pa D = 173.0°; I = -31.3°. Zgornji del profila kaže reverzno paleomagnetno smer, ki jo prekinjata dve normalni magnetozoni. Sodeč po razporeditvi posameznih magnetozon sklepamo, da je vrh najvišje normalno polarizirane cone primerljiv z dogodkom Olduvai (1.76/1.79 Ma) kot najmlajšo možnostjo, ostali del profila pa je lahko le starejši.
A fossil cave, filled with cave sediments was open in the Črnotiče Quarry. An about 1.75 m high section was analysed. Profile consists of banded carbonate rocks intercalated by red clays which was deposited on corroded/ eroded surface of older speleothems. Banded and laminated carbonate rocks are composed of recrystallized calcilutite resemble freshwater limestones. Characteristics of lamination could indicate its origin from organic-rich films. Red clays are composed of quartz, smectite, vermiculite, gibbsite, pM kaolinite, goethite, anatase, rutile, haematite, calcite, micas and feldspar. They contain pellets with Mn hydroxyoxides. That red clays are weathering products redeposited in water-saturated environment. Samples are characterised by intermediate up to high magnetic values of Jn which is caused by the presence of high amount of Fe-minerals. Mean palaeomagnetic directions are for the group of normal palaeomagnetic polarity equal to D = 10.6°; I = 55.0°, and for the group of reverse polarity than D = 173.0°; I = -31.3°. The top part of the profile shows reverse palaeomagnetic direction interrupted by two normal magnetised zones. According to the arrangement of individual magnetozones we assume, that the top of the highest normal polarised magnetozone could be correlated with the Olduvai event (1.76/1.79 Ma) as the youngest possibility, and therefore the rest of profile must be older.
Five samples of clastic sediments from interior cave facies taken in three Slovenian relic caves (Trhlovca, Račiška pečina, and a cave in Črnotiče Quarry, Classical Karst, SW Slovenia) provided invertebrate fossil remains. Most of them belong to Oribatida but sparse individuals of Cladocera and insects were also identified. They represent the first pre-Quaternary invertebrate fossils found in sediments of continental temperate climate. The Pliocene/Pleistocene age of the sediments was determined by paleomagnetic dating chronologically calibrated by micromammal biostratigraphy. Invertebrate fossils could be validated as new proxy for the study of cave sediments due to their suitability for ecological and paleogeographic correlations in caves and outside the caves. They also bring additional information about cave formation and karst hydraulic regime in the area. Even if the number of remains was very low, it represents evidence that climatic conditions in caves allow a better preservation of fossil remains of some groups as compared to most of the surface habitats. This may open a new direction in the study of cave sediments.
This review discusses the connection between quantitative changes of environmental factors and oribatid communities. With the overview of available studies, it can be clearly explored how various characteristics of Oribatid communities are modified due to changes in moisture, temperature, heavy metal concentration, organic matter content and level of disturbance. The most important question concerning the application of Oribatids as indicators is to clarify what kind of information content does natural Oribatid coenological patterns possess from the aspect of bioindication. Most of the variables listed above can be directly measured, since rapid methods are available to quantify parameters of the soil. Responses of Oribatids are worth to study in a more complex approach. Even now we have an expansive knowledge on how communities change due to modifications of different factors. These pieces of information necessitate the elaboration of such methods which render Oribatid communities suitable for the task to prognosticate what extent the given site can be considered near-natural or degraded, based on the Oribatid composition of a single sample taken from the given area. Answering this problem needs extensive and coordinated work.
The age of a karst can be defined as the time when the karst rocks were uplifted out of the sea. The other view of the age of karst is to define the age of certain karst features or assemblages of karst features. On the Kras plateau there is a variety of forms that were formed at quite different times, but due to karst evolution, they coexist in todays relief. On the plateau, that is slowly rising, the hydrological zones in karst surface are moving downwards. Streams from the side ceased to flow on the karst and former leveled surface that was formed in conditions of high ground water is dissected by numerous dolines. Blind valleys are incised at the side and some of them show the influence of recent tectonics. The lowering of relief by corrosion exposes caves that have formed deep beneath the surface and creates unroofed caves that become a part of the surface topography. From the morphological comparison of the unroofed caves, blind valleys and levelled surfaces and by dating of the sediment and considering the age of tectonic phases we can reconstruct the evolution and estimate the age of the karst landscape.
Calcareous tubes, matching those of the modern cave tube worm Marifugia cavatica Absolon & Hrabe (Polychaeta: Serpulidae) in shape and dimensions, were found attached to the wall of a fossilised cave on the Kras plateau, W Slovenia. Due to (1) the supposed absence of any marine influences in that cave, (2) the fact that Marifugia is the only freshwater serpulid known at all, and (3) the mentioned similarity, we suppose that the fossil tubes belonged to the same species or its ancestor. The exact datation would give the first direct data about the minimum "cave age" of an animal species. Towards the end of its hydrological activity, the passage was filled with clay and flowstone. The roof of the passage has been removed by karst denudation and cave is now exposed to the surface. Paleomagnetic datation of the sediment fill shows minimal possible age of 1,7 Ma which is in accordance with the geomorphological observations.
Luoto, T. P. 2009: An assessment of lentic c eratopogonids, ephemeropterans, trichopterans and oribatid mites as indicators of past environmental change in Finland. — Ann. Zool. Fennici 46: 259–270. I studied a dataset of surface sediment samples from 80 lakes with zoological macrore-main analysis to assess the potential of fossil ceratopogonids (Diptera: Ceratopogoni-dae), ephemeropterans (Insecta: Ephemeroptera), trichopterans (Insecta: Trichoptera) and oribatid mites (Acarina: Oribatida) as palaeolimnological indicators in Finland. Results showed that late-winter hypolimnetic oxygen and climatic variables were most important in infl uencing the occurrence and abundance of these taxa. Of the ceratopo-gonids, the Bezzia type was an indicator of elevated hypolimnetic oxygen conditions, warm climate and oligotrophy, while the Dasyhelea type indicated low hypolimnetic oxygen conditions, moderately cool climate and mild acidity. Ephemeropterans, tri-chopterans and oribatids indicated warm climatic conditions and oribatids were also indicative of elevated oxygen conditions and small oligotrophic lakes. Results of this study can be useful in palaeolimnological studies because the fauna examined provides a valuable supplementary data source for multiproxy studies.
We present a 5.3-Myr stack (the "LR04" stack) of benthic δ 18 O records from 57 globally distributed sites aligned by an automated graphic correlation algorithm. This is the first benthic δ 18 O stack comprised of more than three records to extend beyond 850 ka, and we use its improved signal quality to identify 24 new marine isotope stages in the early Pliocene. We also present a new LR04 age model for the Plio-Pleistocene derived from tuning the δ 18 O stack to a simple ice model based on June 21 insolation at 65 • N. Stacked sedimentation rates provide additional age model constraints to prevent overtuning. Despite a conservative tuning strategy, the LR04 benthic stack exhibits significant coherency with insolation in the obliquity band throughout the entire 5.3 Myr and in the precession band for more than half of the record. The LR04 stack contains significantly more variance in benthic δ 18 O than previously published stacks of the late Pleistocene as the result of higher resolution records, a better alignment technique, and a greater percentage of records from the Atlantic. Finally, the relative phases of the stack's 41-and 23-kyr components suggest that the precession component of δ 18 O from 2.7–1.6 Ma is primarily a deep-water temperature signal and that the phase of δ 18 O precession response changed suddenly at 1.6 Ma.
EnglishThe lithostratigraphical, palynological, microfaunal and radiometncal studies of the sediments from the Scladina Cave led us to recognize the classical climatic succession : Eemian, Saint-Germain I, Saint-Germain II, Weichsehan. francaisL'etude lithostratigraphique, palynologique, microfaunique et radiometnque des sediments de la Grotte Scladina nous a conduits a reconnaitre la succession climatique classique : Eemien, Saint-Germain I, Saint-Germain II, Weichselien.
Recently reported radioisotopic dates and magnetic anomaly spacings have made it
evident that modification is required for the age calibrations for the geomagnetic polarity timescale
of Cande and Kent (1992) at the Cretaceous/Paleogene boundary and in the Pliocene. An adjusted
geo-qtagnetic reversal chronology for the Late Cretaceous and Cenozoic is presented that is
consistent with astrochronology in the Pleistocene anq Pliocene and with a new timescale for the
Mesozoic.
For the first time in the Classical Karst, paleontological data enabled to match the magnetostratigraphic record precisely with the geomagnetic polarity timescale in two studied sites: (i) a series of speleothems alternating with red clays in Račiška pečina Cave (Matarsko podolje), and (ii) an unroofed paleocave of the Črnotiče II site (Podgorski kras Plateau) completely filled by fluvial clastic sediments covered by speleothems. The later sites are also characterized by a rich appearance of fossil tubes of autochthonous stygobiont serpulid Marifugia cavatica. The vertebrate record is composed mostly of enamel fragments of rodents and soricomorphs. Absence of rootless arvicolids as well as taxonomic composition of the mammalian fauna suggests the Pliocene age of both sites. For (i) Račiška pečina (with Apodemus, cf. Borsodia) it was estimated to middle to late MN17 (ca 1.8–2.4 Ma), while (ii) the assemblage from Črnotiče II (with Deinsdorfia sp., Beremedia fissidens, Apodemus cf. atavus, Rhagapodemus cf. frequens, Glirulus sp., Cseria sp.) is obviously quite older: MN15–MN16 (ca 3.0–4.1 Ma). In respect to congruence of biostratigraphic and paleomagnetic data and a reliable sedimentary setting of the samples we propose to apply the respective datum also as the time of one ancient speleogenetic phase in the Classical Karst.
The Postojnska jama–Planinska jama cave system and number of smaller adjacent caves are developed in the Postojnski kras. These caves are located between two dextral strike-slip fault zones oriented in the Dinaric direction. The caves contain lithologically diversified cave fill, ranging from speleothems to allogenic fluvial sediments. The allogenic clastic material is derived from a single source, Eocene siliciclastics of the Pivka Basin. Small differences in mineral/petrologic composition between the sediments can be attributed to different degrees of weathering in the catchment area and homogenization of source sediments. Thick sequences of fine-grained laminated sediments, deposited from suspension are common. The depositional environment was mostly calm, but not completely stagnant. Such a sedimentary environment can be described as cave lacustrine, with deposition from pulsed flow. The homogeneity of the palaeomagnetic data suggests rapid deposition by a number of short-lived single-flood events over a few thousand years. This depositional style was favourable for recording of short-lived excursions in the palaeomagnetic field. The sediments were originally not expected to be older than Middle Quaternary in age (i.e. about 0.4 Ma). Later numerical dating (Th/U and ESR) indicated ages older than 0.53 ka. New palaeomagnetic data from selected sedimentary profiles within the cave system detected normal polarization in much of the profiles studied. Reverse polarized magnetozones, interpreted mostly as short- lived excursions of magnetic field, were detected in only a few places. Therefore, we interpreted most of the sediments as being younger than 0.78 Ma, belonging to different depositional phases within the Brunhes chron. Palaeomagnetic properties of two profiles in caves intersected by the artificial tunnel between Postojnska jama and Črna jama had reverse polarized magnetozones and of sediments in Zguba jama, may indicate an age much greater than 0.78 Ma. The cave system has evolved over a long period of time, governed by the functioning of Planinsko polje in the relation to the evolution of the resurgence area in Ljubljana Moor further to the east. General stabilization of the hydrological system with low hydraulic head led to the evolution of caves in epiphreatic and paragenetic conditions over a long time-span. Individual cave segments or passages were completely filled and exhumed several times during the evolution of the cave. Alternation of depositional and erosional phases may be connected with changing conditions within the cave system, the functioning of the resurgence area, collapse, climatic change, tectonic movement and the intrinsic mechanisms of contact karst.
AnsTracT-Minute, sclerotized, chelicerate arthropods which form the Suborder Oribatida in the
Order Acaraformes, often known as "moss mites" or "soil mites" in response to their habitat
preferences, are ubiquitous members of the soil arthropod fauna responsible for recycling nutrients
as they feed upon detrital plant material and fungal matter. Because oribatid mites are abundant,
have narrow habitat preferences through awide range of ecotopes, and are likely to be fossilized
within their local ranges, they offer high-resolution paleoclimatic and vegetative information and
promise to become a powerful tool in Quaternary paleoecological studies.
At Glovers Pond, in northern New Jersey, paleolimnologic setting, facies distributions, and
chronologies of the basin-fill sequence indicate cyclic episodes of lake shallowing followed by
relatively rapid return to normal. At this site fossil oribatid mites occur in all sediment types except
clays. Average numbers of 1.2 specimens/gm (dry wt.) of sediment in profundal gyttja, 14.1/gm
in shelf-type marl, and 3.0/gm in strandline peat were recorded. Maximum recovery was 24.5/gm.
Sample size of 10 gm (dry wt.) is recommended as a standard for comparison. The aquatic taxa
Limnozetes cf. L. rugosus (Sellnick) and Hydrozetes oryktosis Woolley were the most abundant
taxa; more than twenty terrestrial (allogenic) genera occur commonly, additional taxa more rarely.
More than 10,100 oribatid specimens have been extracted from 135 samples, whereas only two
beetle elytra have been taken from the same samples.
Five classes of preservation are defined and illustrated. These provide a qualitative guide used
to analyze oribatid taphonomic information. Quantities of mites are related to paleolimnological
parameters such as water depth and nutrient content. Abundance data from Glovers Pond show
that, through several cycles, numbers of fossils (and mite populations) increased in response to
deepening of the lake and waned as the lake shallowed. These abundance fluctuations reflect local
climatic variations. It is anticipated that quantitative studies of oribatid abundances will provide
useful fine-scale paleoecological data similar to those from pollen or beetles
The degree to which post-depositional disturbance can be assessed in archaeological sequences is critical for the development of robust chronologies for such deposits. A common approach is the identification of conjoined artefacts distributed through the sequence as a measure of disturbance following deposition, although this method is relatively labour intensive and does not provide a continuous record of disturbance through the entire sequence. Here we present δ13C values for different size fractions (<125 and >125 µm) of chemically resistant charcoal distributed through a sedimentary profile at Allen's Cave, South Australia. The curves generated from both size fractions parallel one another, indicating minimal disturbance through the entire profile and providing greater confidence in the luminescence and radiocarbon chronologies reported previously for the site. In addition, the elemental δ13C values provide an indication of greater aridity (compared with present) persisting in this area from ca. 45 to 12 ka, consistent with other proxy records. The onset of the Holocene is marked by a shift to wetter conditions, probably as a result of post-glacial marine transgression and closer proximity to the coastline. Copyright © 2001 John Wiley & Sons, Ltd.
Oribatid mite studies are now reaching the mainstream of Quaternary investigation as researchers seek additional methods for recognizing climate change based on organismal proxies of habitat. Rewards of information are potentially large. The oribatid fossil record is very robust and full of subtlety that will emerge from the careful efforts of knowledgeable paleoacarologists. Because they do not fly as beetles do, nor blow long distances on the wind as many pollen species do, they offer excellent characteristics as proxies of local habitat and climate, particularly when those are a reflection of moisture conditions. Applications to both archaeology and Quaternary geology arise from quantitative studies of mite stratigraphic zonation, from faunal assemblages, from taphonomic analysis and from the use of individual species as proxies of systemic change.Temperature-related productivity changes are reflected by population densities of species of the aquatic mite genera Hydrozetes and the Sphagnum-dwelling Limnozetes. Quaternary moisture ranges or hydrologic conditions are revealed by mite assemblages in lake and bog sediments and even in cave stalagmites or spring deposits. Close sampling of cores permits extraction of subtle paleoclimate data when terrestrial mite population counts are plotted against counts of the aquatic taxa. Analysis of taphonomic class and Preservation Index can reveal hidden unconformities in homogeneous stratigraphic sections.
Članek je poročilo o odkritju cevk jamskega cevkarja v brezstropi jami v kamnolomu nad Črnim kalom. Opisano je nahajališče ter oblika fosilnih cevk. Živali so živele pritrjene na fasetirano steno rova. Rov je nato zapolnila ilovica, nato pa še več metrov debela siga. Strop rova in njegov gornji del je kraška denudacija že odstranila, tako da sega siga že na površje. Na skalni steni so se ohranili prirasli deli cevk različno velikih živali, deli cevk, ki so rasli pravokotno na steno pa so se odlomili, vendar so se ohranili v sedimentu. Cevke so po dimenzijah in obliki podobne cevkam recentnega jamskega cevkarja Marifugia cavatica Absolon in Hrabe. Po legi ohranjenih cevk ter dataciji bližnjih sedimentov s paleomagnetno metodo sodimo, da so ostanki cevkarjev najmanj pliocenske starosti.
The paper is a report on the discovery of tubes of a fossilized cave serpulid in a roofless cave in the quarry above Črni Kal village. The site and shape of the fossilized tubes are described. The animals lived attached to the scallops in the wall of the passage. The passage was later filled with clay deposits, followed by a layer of flowstone several metres thick. The roof of the passage has been removed by karst denudation and flowstone now reaches to the surface. Fragments of tubes of animals of various sizes have been preserved, attached to the rock wall; those tubes which grew at a right angle to the wall have broken off but have been preserved in the sediment. In terms of their dimension and shape the tubes remind one of the tubes of the more recent cave serpulid Marifugia cavatica Absolon and Hrabe. The positions of the preserved tubes and the dating of the nearby sediments by palaeomagnetic method indicate that the remains of the serpulids are from the Pliocene epoch or older.
Trije profili jamskih sedimentov (v fosilni jami blizu Divače, v Divaški jami in v Trhlovci) so bili preučeni na Krasu blizu Divače. Mineraloška analiza izpričuje relativno enotno sestavo lahke frakcije in kaže na glavni izvor v preperelih ostankih eocenskega fliša. Nekaj mineralov je produkt preparevanja (npr. gibbsit). Podrobna magnetostratigrafska raziskava treh profilov kaže na normalno in reverzno polarnost magnetocon in kaže na korelacijo med profiloma v Divaški jami in Trhlovci. Ozke normalne magnetocone verjetno sovpadajo z Jaramillo polarnostjo (0.90 do 0.97 Ma) v Matuyama epohi. Podatki kažejo na precejšnjo starost jame, v kateri je nastopilo zadnje obdobje zapolnjevanja pred 0,97 Ma in se končalo pred mejo med Brunhes/Matuyama, pred približno 0.73 Ma. Magnetostratigrafski podatki profila pri Divači so zabeležili dve ozki normalni magnetoconi v dolgi reverzni polarni coni, kar verjetno sovpada z Olduvai oz. Reunion (okrog 1.67 do 1.87 Ma) reverzne Matuyama epohe ali z normalnimi magnetoconami (okrog 3.8 d0 5.0 Ma) v reverzni Gilbert epohi. Podatki nakazujejo možnost, da je jama nastala v mesinski stopnji, za katero je značilen padec morske gladine in razvoj globokega krasa v Mediteranu.
Three profiles of caves sediments (Divača fossil cave, Divaška Jama and Trhlovca Cave) were studied in the Kras near Divača village. Mineralogical study proved relatively uniform mineral composition of the light fraction indicating the main source from weathered sediments of Eocene flysch. Some minerals are derived from weathering profiles and crusts (e.g. gibbsite). Detailed magnetostratigraphic investigations of three profiles defined normal and reverse polarity magnetozones and shows the correlation between the profiles in the Divaška Jama and Trhlovca Cave. The narrow normal magnetozones probably correlate with the Jaramillo polarity event (0.90 to 0.97 Ma) of the Matuyama epoch. Those data indicate the substantial age of cave in which the last phase of filling started before 0.97 Ma and finished before the Brunhes/Matuyama boundary, i.e. around 0.73 Ma. Magnetostratigraphic data of the Divača profile detected two narrow normal magnetozones in the long reverse polarity zone which probably correlate with Olduvai and Reunion polarity events (about 1.67 to 1.87 Ma) of reverse Matuyama epoch or with some of normal magnetozones (about 3.8 to 5.0 Ma) within reverse Gilbert epoch. Data indicate the possibility that the cave was originated during the Messinian period characteristic by sea-level fall and evolution of deep karst in the Mediterranean Basin.
Highly derived oribatid mites (Brachypylina) seem to fit most predictions of evolutionary theory regarding the ecological, geographical and taxonomic distribution of parthenogenesis. Earlier derivative groups generally do not. We suggest that the ancestors of large, completely parthenogenetic families (for example, Brachychthoniidae, Lohmanniidae, Camisiidae, Trhypoch-thoniidae, Malaconothridae, Nanhermanniidae) were themselves parthenogenetic, and that’ speciation’ and radiation occurred in the absence of sexual reproduction. Further, it is speculated that automixy (meiotic thelytoky) was the process involved — even though some extant species may prove to be secondarily apomictic, just as apomicts evolve from sexually reproducing lineages. If mechanisms for maintaining heterozygosity are effective, automixy can provide all the advantages of parthenogenesis, plus the DNA-repair advantage of meiosis. Genotypes can be diversified by the formation of distinct clones, thereby providing the raw material for successful radiation. The disadvantage of such a system would be its slow rate of change due to the absence of an allele-recruitment mechanism. Much of the above remains speculative since available data are meagre. Future work should include surveys of thelytokous mechanisms in oribatid mites, the genetic characterization of populations of a variety of parthenogenetic and sexual species, and the refinement of hypotheses on phylogenetic relationships of parthenogenetic taxa.
Clastic sediments have played an important role in deciphering geologic history and processes since the inception of the discipline. Early studies of caves applied stratigraphic principles to karst deposits. The majority of cave deposits are breakdown and alluvium. The alluvial materials have been successfully investigated to determine ages of caves, landscape evolution, paleoenvironmental conditions, and paleobiota. Rapid stage changes and the possibility of pipe-full flow make cave deposits different than surface deposits. This and other factors present difficulties with interpreting the cave record, but extended preservation is afforded by the "roofing" of deposits. Dating by magnetism or isotopes has been successful in many locations. Caves can be expected to persist for 10 Ma in a single erosive cycle; most cave sediments should be no older than this.
In order to assess the relationship between surface soils and sediment deposits in the karst of westcentral Florida, excavations were completed within a cave and on the surface above the cave. Historical climatic and land use data were also compiled for the area. A one metre deep excavation in the cave revealed seven distinguishable strata, with the uppermost 0.52m (five strata) formed over the last 18 years. Below 0.52m, the sediments contain thin laminae that formed when sandy sediments washed into the cave during the summer rainy season. The surface soil consists of sandy A, E, and B horizons underlain by a Bt horizon which formed as a weathering product of the limestone bedrock located 0.76m below the surface. Grain size, roundness, and sphericity data from the cave sediment strata and soil horizons indicate that the cave sediment is allogenic, with the source being the sandy surficial soft horizons (A, E, and B). The rate of sedimentation in the cave has been accelerated by the construction and maintenance of area forest roads, and general forestry practices.
[1] We present a 5.3- Myr stack ( the " LR04'' stack) of benthic delta(18)O records from 57 globally distributed sites aligned by an automated graphic correlation algorithm. This is the first benthic delta(18)O stack composed of more than three records to extend beyond 850 ka, and we use its improved signal quality to identify 24 new marine isotope stages in the early Pliocene. We also present a new LR04 age model for the Pliocene- Pleistocene derived from tuning the delta(18)O stack to a simple ice model based on 21 June insolation at 65degreesN. Stacked sedimentation rates provide additional age model constraints to prevent overtuning. Despite a conservative tuning strategy, the LR04 benthic stack exhibits significant coherency with insolation in the obliquity band throughout the entire 5.3 Myr and in the precession band for more than half of the record. The LR04 stack contains significantly more variance in benthic delta(18) O than previously published stacks of the late Pleistocene as the result of higher-resolution records, a better alignment technique, and a greater percentage of records from the Atlantic. Finally, the relative phases of the stack's 41- and 23- kyr components suggest that the precession component of delta(18)O from 2.7 - 1.6 Ma is primarily a deep- water temperature signal and that the phase of delta(18)O precession response changed suddenly at 1.6 Ma.
Magnetic susceptibility was measured for 630 samples from Holocene sediments taken from Konispol Cave, sw Albania. Comparisons between magnetic susceptibility profiles from three trenches within the cave show distinctive variations in magnetic susceptibility magnitudes and patterns that, in turn, allow direct correlations between trenches and estimates of small-scale sedimentation rate changes. Using 14C dates in conjunction with magnetic susceptibility variations in individual trenches, we have constructed a composite susceptibility profile. Trends toward increasing magnetic susceptibility from ca. 8,000 to 4,000 years b.p. are consistent with the long-term paleoclimatic warming trends that have been reported elsewhere. Short-term fluctuations are attributed to short-term temperature changes and varying availability of moisture for pedogenesis. Lower susceptibilities indicate times of drier/cooler conditions, while high values represent moist/warm climates. We conclude that the magnetic susceptibility fluctuations observed in samples from the cave result from shifts in paleoclimate and reflect changes in magnetic mineral concentration, primarily maghemite, produced during pedogenesis of those sediments washed into the cave.
Caves serve as unique repositories for geologic, biologic, and anthropologic information. The sediments within these natural cavities are incredibly diverse. They include secondary minerals such as calcite and gypsum, which occur in sundry forms, as well as allogenic and autogenic clasts. This book is for any geoscience researcher or student with interests in climate change, paleohydrology, karst geology, and sedimentology. It is the first comprehensive volume on cave sediments. It provides case-studies from around the world, gives guidance on appropriate applications of techniques, and their limitations, synthesizes methods that can be used to decipher complex deposits, and includes chemical deposits (speleothems) as well as clastic sediments.
Results are presented of palynological and sedimentological research at the Palaeolithic site of Perneras Cave (coastal Murcia, southeastern Spain). Sedimentological features point to a warm, somewhat humid phase corresponding with the lowermost part of the Mousterian sequence, which was followed by a climatic deterioration which lasted throughout the later Mousterian and Upper Palaeolithic. The palynological study described here barely allows palaeoclimatological inferences to be drawn, but it does highlight interesting paleobotanical data, namely, the presence of Ibero-Maghrebian and Mediterranean elements, which suggest that the site was an important refuge for thermophilous taxa. The reliability of the interpretation of the pollen assemblages is assessed in terms of the incorporation, preservation and distribution of pollen grains into the profile.
The results of a palynological investigation of the Upper Palaeolithic interval from the Beneito Cave (southeastern Spain) are herewith considered in the context of results from a previous report on the underlying deposits. Two new percentage and concentration pollen-diagrams with good correspondence are presented. The Upper Palaeolithic sequence is dominated by Poaceae, Chenopodiaceae and Artemisia, whereas arboreal pollen are less important. Mesophilous trees and Mediterranean taxa show a constant presence, but in low proportions. The new data add support to the view that interpleniglacial development of Mediterranean taxa was important in eastern Spain, while they were considerably reduced during upper pleniglacial times. Emphasis is placed on aridity as a limiting factor in influencing major vegetation changes in the area. Two additional topics are also presented: they deal with the extrapolation of north European interstadials to Mediterranean Spain and the palaeoecological value of archaeopalynological records.
Soil is an important compo- nent for monitoring of sustainability of land use in relation to both the conservation of natural resources and biodiversity of ecosystems. Re- cently research has focused on the role of mites (Acari) in biomonitoring and their importance as soil bioindicators. Mite communities are ex- tremely sensitive to all types of soil disturbance. This article presents a review of some studies on mite communities in order to discuss whether the diversity and numbers of mites present in the soil can reflect human impact on ecosystems and landscape, and whether mites can be used in monitoring systems. Limited data available about mite communities in agricultural ecosys- tems (in use and abandoned) in SW Norway from author's own studies (published and in prep.) are compared with data from ca. 55 pa- pers (mostly concerning Europe).
Future warming projected by the Intergovernmental Panel on Climate Change (IPCC) has the potential to affect every person on Earth. Extreme weather events, rising sea level, and migrating ecosystems and resources may result in socioeconomic stresses. Although we can plan and prepare for what is expected, the most dangerous aspect of our changing climate is the uncertainty in climate sensitivity.
To reduce the uncertainties of climate change, paleoclimatologists are focusing on a possible yet imperfect analog to a future warmer climate.
The quaternary sciences constitute a dynamic, multidisciplinary field of research that has been growing in scientific and societal importance in recent years. This branch of the Earth sciences links ancient prehistory to modern environments. Quaternary terrestrial sediments contain the fossil remains of existing species of flora and fauna, and their immediate predecessors. Quaternary science plays an integral part in such important issues for modern society as groundwater resources and contamination, sea level change, geologic hazards (earthquakes, volcanic eruptions, tsunamis), and soil erosion.
Kulna Cave is located in the Moravian Karst, a well-developed karstic region formed in Devonian limestones in the eastern part of the Czech Republic. The entrance facies sediments in the cave consist of interbedded layers of silts (loess) and clay-rich silts (loam) that were either directly blown into the cave entrance or redeposited in the cave by slope processes during the Last Glacial Stage. The layers of loess and loam overlie fluvial sands and gravels deposited during the Last Interglacial. Previous research at Kulna concentrated on the archaeology, palaeontology and dendrology of these entrance facies sediments. From these data, palaeoenvironmental conditions in the vicinity of the cave were reconstructed. Our results suggest that susceptibility variations and in particular variations in pedogenic susceptibility yield a more detailed record of the palaeoenvironmental conditions at the cave during the Last Glacial Stage.
The presence of at least 12 species of well-preserved mites in two late
Holocene stalagmites from Hidden Cave, Guadalupe Mountains, New Mexico,
depicts changing climate over the past 3200 yr. Growth of both
stalagmites, determined by uranium-series dating, occurred from at least
3171 ± 48 yr ago and ceased by 819 ± 82 yr ago. Some of
the 12 subfossil genera and species in the stalagmites are like those
currently found in wetter and cooler climates, northern-like, and
distinctly different from those known in the cave (n = 16) and on the
surface immediately around the cave (n = 32). The mismatch of genera and
species in the stalagmites, cave, and surface near the cave argues for a
wetter and cooler late Holocene climate in the southwestern United
States from ca. 3200 to 800 yr ago.
Multivariate statistical techniques were used to examine the relationships between surface-sediment cladoceran assemblages and 28 physical and chemical variables in 53 small subarctic lakes from northern Fennoscandia. The lakes were distributed along a steep eco-climatic gradient, spanning boreal corniferous forest to treeless tundra. In general, the sites were small, oligotrophic, and bathymetrically simple, with little or no disturbance in their catchments. From the initial 53 localities, only 36 contained a sufficient number of cladoceran remains for reasonable quantification. From these, a total of 29 cladoceran taxa representing 19 genera were identified, comprising predominantly littoral chydorid species. A constrained redundancy analysis (RDA) and associated Monte Carlo permutation tests indicated that maximum lake depth, sediment organic content, epilimnetic summer temperature, lake perimeter, and lake catchment area made statistically significant (p le; 0.05) contributions to explaining the variance in the cladoceran taxon data. These five variables together accounted for 67.7% of the explained variance, and made a unique contribution of 26.8% to the total variance: all physical determinants independently captured 33.2% of the total variance. The significance of the most powerful explanatory variables is discussed in the paper in detail, and autecological information regarding the most common cladoceran taxa is given.
In this paper, we describe a new method for quantitative reconstruction of bioclimate using a combination of multi-scale ecological datasets of present-day distributions of species with fossil plant and bird data derived from cave deposits of known age. In the specific case of Gorham's Cave, Gibraltar, we make predictions as to the prevailing climate during the Last Glacial Maximum (LGM). Our results indicate only slight variations compared to present-day climate. The present-day climatic regime is encompassed by a wider regime during the LGM. The importance of caves as climate archives is highlighted and our results additionally give focus to the generally underestimated importance of small-scale refugia during glacials.
The general ecology, biology, life history, and available sources for identification of oribatid mites (including Astigmata), the most numerically dominant arachnid group in the organic horizons of most soils, is reviewed. I use this information as the basis to evaluate data on their role for bioindication in agroecosystems, with the following conclusions: (a) oribatid mites with their low metabolic rates, slow development and low fecundity cannot respond rapidly to resource flushes: astigmatic mites with their contrasting life history traits can respond rapidly; (b) because many agroecosystems represent early successional stages, the oribatid species present are those found in heavily disturbed or early successional habitats, wherever these occur; (c) use of oribatid mites for bioindication must incorporate information on life history traits, and habitat and niche profiles for species.
Results are presented of palynological analyses of Pleistocene deposits at Cova Beneito, an archaeological site on the southern slopes of the Sierra de Benicadell, Alicante province (SE Spain), 650 m a.s.l. with a WSW orientation. The chronology is supported by radiocarbon dating, archaeological evolution, previous local sequences, and recourse to several wider correlations. For the first time in the region, a warming event is defined in the mid-last glacial stage. During this event, vegetation took on a Mediterranean character with sclerophyllous elements such as Quercus, Olea, Phillyrea, Rhamnus, Helianthemum, etc. The rest of the sequence shows a predominance of Pinus within the AP, phases of steppe-like character, and an aridity-crisis immediately after the climate improvement. Due to local conditions, forest cover was never very great.
This study forms part of an interdisciplinary research project, the aim of which is to provide a regional palaeoecological sequence suitable for inter-regional comparisons. Carihuela Cave is a major archaeological site in the Granada province of eastern Andalusia. It falls within the Upper Mesomediterranean bioclimatic belt, lies at 1020 m a.s.l. and has a northerly aspect. An overview of the background of archaeological, palaeontological, sedimentological, and geochronological research at the cave is followed by a presentation of new palynological data from its Pleistocene deposits. The sediments contain Middle Palaeolithic artefacts and are of exogenous origin. Samples for pollen analysis were taken from five stratigraphical sections and a pollen diagram was drawn up for each. Correlation of these permitted two synoptic diagrams to be constructed, with the exclusion in one of them of Asteraceae pollen other than Artemisia and Centaurea.
A litterbag experiment was used to study the impact of extended periods of summer drought on the structure of oribatid mite communities (Acari, Oribatida) developing in two litter types (beech, spruce) of two qualities (fresh, pre-incubated). Within each litter type, litter quality determined species composition and densities and, in turn, this determined the impact of drought upon the oribatid mite communities. In both litter types, drought had a greater impact on community development in the pre-incubated compared to the fresh litter. In the short-term perspective of the present study, oribatid mite communities in beech litter were less sensitive to summer drought than those in spruce litter. This was partly due to the presence of site-specific, drought-tolerant species but seemed also strongly related to differences in the decomposition patterns between the litter types. Marked changes in densities and composition of oribatid communities after only one period
of summer-drought suggest that there is a potential for a significant alteration of oribatid community structure in both litter types if climatic changes persist.
Recently reported radioisotopic dates and magnetic anomaly spacings have made it evident that modification is required for the age calibrations for the geomagnetic polarity timescale of Cande and Kent (1992) at the Cretaceous/Paleogene boundary and in the Pliocene. An adjusted geomagnetic reversal chronology for the Late Cretaceous and Cenozoic is presented that is consistent with astrochronology in the Pleistocene and Pliocene and with a new timescale for the Mesozoic.
The purpose of this paper is to illustrate how calcareous sediments from Pleistocene and Holocene rockshelters and open caves of the Western Mediterranean can provide a stratigraphic record of abrupt climate change. The method proposed here is based on microstratigraphic examination of sedimentary sequences using microscopic techniques. The most important processes for characterizing the sensitivity of each cave to climate variables are: (1) the modes and rate of carbonate sediment production, (2) the nature and intensity of the pedogenic processes responsible for the synchronous alteration of carbonate materials (either those derived from the cave walls or those deposited on the ground surface), and (3) the supply of allogenic sediments, particularly by eolian activity. The cave sediment sequences presented record the marked coolings known as Dansgaard-Oeschger stadials and Heinrich events that occurred during the Pleistocene and the Holocene, as demonstrated by the high resolution records from ice and deep sea cores. At Abric Romanì in northeastern Spain, a series of sharp climatic deteriorations of increasing severity is shown to have occurred synchronously with the transition from the Middle to the Upper Paleolithic, with a period of seasonal frost and strong winds at ca. 37,000 yr B.P., tentatively correlated with Heinrich event 4. At Pigeon Cave, Taforalt (northern Morocco), the transition from the Aterian to Ibero-Maurusian/Epipalaeolithic cultures is dated to around 24,000–20,000 yr B.P. and is punctuated by a series of short cold pulses with evidence for seasonal freezing, soil erosion, and minimal evapotranspiration. In El Miron cave in north-central Spain, the exceptional nature of the Younger Dryas cooling produced a marked destabilization of the cave walls and roof. At El Miron, the stratigraphic evidence for sediment removal due to the rapid percolation of snow melt under a degraded soil cover allows us to reconstruct the nature of the negative excursion at ca. 8200 yr B.P. This example also illustrates how climate-controlled pedogenic processes can create a stratigraphic signature which has often been confused with a sedimentary hiatus. We conclude that cave sediments provide a valuable record of Pleistocene and Holocene climate changes. In appropriate contexts, these sequences allow us to examine the ecological stress generated by these unique global events at a local and regional level and improve our understanding of the complex anthropological processes that occurred at the same time. © 2001 John Wiley & Sons, Inc.