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Paleoecology of Benthic Foraminifera in Coral Reefs Recorded in the Jurassic Tuwaiq Mountain Formation of the Khashm Al-Qaddiyah Area, Central Saudi Arabia
Abstract
Thirty three benthic foraminiferal species belong to 23 genera and 16 families have been
recorded from the coral reefs of the Callovian Tuwaiq Formation, Khashm Al-Qaddiyah area, Central
Saudi Arabia. Three species: Astacolus qaddiyahensis, Nodosaria riyadhensis, Siderolites jurassica are
believed to be new. Nearly all identified foraminifera are of Atlantic-Miditeranean affinity. The foraminiferal
assemblage recorded in the present work is mixed of open marine, moderately deep marine
conditions associations and shallow to deep lagoon. The reefal part of upper Twiaq Formation
may have been deposited in shallow water of lower to middle shelf depth (20–50 m) as indicated by
abundant corals and benthic foraminifera. The coral fauna and bearing benthic foraminifera indicated
moderate water energy.
Supplementary resource (1)
... The geological map of the area presented in Figure S1 indicated that the sedimentary strata include a mix of Mesozoic and Cenozoic formations, reflecting varying depositional environments over time. The Mesozoic and Cenozoic sequence consists of Jurassic Dhruma, Tuwaiq Mountain limestone, Hanifa formations, and Quaternary deposits [31,32]. The Jurassic strata are characterized by extensive carbonate platforms, representing pure marine carbonate deposition. ...
Heavy metal contamination in soil is a global issue threatening human health and ecosystems. Accurate spatial maps of heavy metals (HMs) are vital to mitigating the adverse effects on the ecosystem. This study utilizes GIS and multivariate analysis to evaluate HMs in agricultural soils from Al Ghat Governorate, Saudi Arabia, analyzing Al, As, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn using ICP-AES in 35 soil samples. Methods included contamination factor (CF), enrichment factor (EF), risk index (RI), geoaccumulation index (Igeo), pollution load index (PLI), soil quality guidelines (SQGs), and multivariate analysis. The soils, characterized by sandy texture, low organic matter, and alkalinity due to arid conditions and high calcium carbonate, had the following HM concentrations (mg/kg) in descending order: Fe (11,480) ˃ Al (7786) ˃ Mn (278) ˃ Zn (72.37) ˃ Ni (28.66) ˃ V (21.80) ˃ Cr (19.89) ˃ Co (19.00) ˃ Cu (12.46) ˃ Pb (5.46) ˃ As (2.69). EF, CF, and Igeo suggest natural sources for most HMs, predominantly from the sedimentary sequence, with localized Zn, Pb, Co, Mn, and Cu enrichment linked to mixed natural and agricultural influences. PLI and RI indicated acceptable contamination levels, posing no ecological risk. All samples fell below SQG thresholds for As, Cu, Pb, and Cr, confirming minimal ecological threat. Statistical analysis highlighted sedimentary cover as the primary HM source, with agricultural activities contributing to Co, Cu, Ni, and Pb levels.
... These variations in composition and pore structure can significantly impact the mechanical properties and chemical stability of CRL, especially in the shallow layers with aragonite dominant and porosity greater than 50% Wu, Meng, Wang, Qin, & Dong, 2023). Which are vulnerable to environmental changes, including ocean acidification and geological activity (Humphreys et al., 2022;Youssef & El-Sorogy, 2015). Consequently, a comprehensive understanding of the mechanical properties and dissolution behavior of the shallow commonly found aragonite-component CRL structure is essential for promoting the sustainable development of coastal infrastructure and ensuring their long-term operational stability. ...
Plain Language Summary
The shallow coral reef limestone (CRL), primarily composed of aragonite, originates from the skeletal remains of dead corals and serves as a fundamental material in island reef construction. Understanding its structural properties is essential for ensuring the integrity and stability of island reefs. Due to its unique formation process and the prevalence of aragonite, the CRL generally exhibits an extensive internal pore structure, making it more susceptible to environmental influences. To investigate the effects of dissolution on the structure, nanoindentation tests were conducted to evaluate changes in the micromechanical properties. Due to the rarity of rock samples, nanoindentation enables the quantification of mechanical changes from the microscale to the macroscale through the Mori‐Tanaka method. Simultaneously, CT scanning and image processing techniques were employed to convert real pore structure information into mathematical representations. To achieve more precise modeling of complex micrometer‐scale pore structures, a numerical model based on the level‐set method is employed, which facilitates the study of static dissolution under varying temperature and mineral conditions. Simulations showed that as temperature rises, both the dissolution volume and porosity increase, but the changes in pore radius were more complex. The presence of aragonite suppressed calcite dissolution, thereby altering the dissolution pathway. Furthermore, extracting the structure before and after dissolution and combining it with nanoindentation results enables a visualized analysis of the effects of pore on macromechanical properties. Overall, these findings suggest that dissolution, influenced not only by acidification but also by temperature and mineral composition, drives the evolution of pore structures and ultimately impacts the mechanical properties of CRL.
... The stratigraphy and fossil content have been studied by many authors (e.g. Galal and Kamel, 2004;Hughes, 2004Hughes, , 2006Hughes, , 2008AL-Saad, 2008;El-Sorogy et al., 2014;Youssef and El-Sorogy, 2015;El-Sorogy and Al-Kahtany, 2015). ...
This article deals with the Upper Jurassic carbonates of the Jubaila Formation, exposed throughout the Tuwaiq Mountains, Central Saudi Arabia and discusses the succession of palaeoenvironments resulting from detailed field and lab work. Based on microfacies analysis and sedimentological data, twelve facies are identified within the Upper Jurassic carbonates at Wadi Hanifa, Central Saudi Arabia. These facies are attributed to six main facies belts. Within these facies and facies belts, four distinct biofacies assemblages are recognized. Deposition took place on an extendable ramp, which probably dipped gently eastwards to the sea. A depositional model relates the identified facies and biofacies to a downdip depositional profile of an inner, middle and outer carbonate ramp. The burrowed lime mudstone and bioclastic wackestone-floatstone of facies belt 1 accumulated in a distal middle ramp to outer ramp. The mollusk-coated grains-intraclast rudstone of facies belt 2 were deposited in the distal middle ramp. The branched stromatoporoids Cladocoropsis were deposited in the proximal middle ramp of facies belt 3. The facies of the open lagoon (facies belt 5) and the tidal-flat (facies belt 6) were deposited in the inner ramp behind the ramp crest/shoal facies belt 4. The Early Kimmeridgian Jubaila Formation has been deposited as transgressive and highstand deposits of a third-order depositional sequence, which are mainly controlled by eustatic sea-level changes. During the transgression, an aggradational trend developed , with the construction of a deep subtidal facies of small-scale stacked cycles of mudstones with frequent mottled firm ground and hard ground, storm beds and tempestites. The regressive part has a characteristic progradational trend, with shallow-water carbonate platform deposits arranged into meter-scale coarsening-upward cycles ranged from dolomitic mudstone and wackestone to stromato-poroid packstone and rudstone into bioclastic intraclastic peloidal packstone and grainstone.
... The Callovian Tuwaiq Mountain Limestone Formation consists mainly of carbonate rocks and extends for more than 1200 km from south to north in central Saudi Arabia. In the subsurface the formation forms the major source-rock in the anoxic basins of the Middle East (Powers et al., 1966;Powers, 1968;Vaslet et al., 1983;Al Sharhan and Magara, 1995;El-Sorogy et al., 2014;Youssef and El-Sorogy, 2015). It was deposited on a carbonate platform developed across the intra-shelf basin (Ziegler, 2001). ...
Sequence stratigraphy of the late middle Jurassic open shelf platform
of the Tuwaiq Mountain Limestone Formation, central Saudi Arabia
... The Callovian Tuwaiq Mountain Limestone Formation consists mainly of carbonate rocks and extends for more than 1200 km from south to north in central Saudi Arabia. In the subsurface the formation forms the major source-rock in the anoxic basins of the Middle East (Powers et al., 1966;Powers, 1968;Vaslet et al., 1983;Al Sharhan and Magara, 1995;El-Sorogy et al., 2014;Youssef and El-Sorogy, 2015). It was deposited on a carbonate platform developed across the intra-shelf basin (Ziegler, 2001). ...
... 4). The echinoids were described byKier (1972) and Melville (1955). More recently, El-Sorogy et al. (2014carried out a paleontologic study on the various fauna (corals, brachiopoda and mollusca) of the upper Jurassic Tuwaiq Mountain Limestone, central Saudi Arabia. ElSorogy and Al-Kahtany (2015)studied corals of the Upper Jurassic Hanifa Formation.Youssef and El-Sorogy (2015)studied benthic foraminifera in the Jurassic reefal part of the Tuwaiq Mountain Formation. The present study aims to revise the macrofossil content encountered in the Marrat Formation from the taxonomic point of view and to study their stratigraphic position and distribution in the formation. It aims also to correlate the identified spec ...
The stratigraphy and macrofaunal content of the Lower Jurassic (Toarcian) Marrat Formation was studied at Khashm adh Dhibi, central Saudi Arabia. The studied succession is dominated by limestones and dolomites, with subordinate occurrences of sandstones, siltstones and claystones. The formation is highly fossiliferous with brachiopods, gastropods, bivalves, ammonites and echinoids, particularly the lower and upper members. Twenty nine species are identified, they include 7 species of brachiopods, 8 gas-tropods, 8 bivalves, 4 ammonites and 2 echinoids. Many of the identified fauna are correlated with Jurassic equivalents in Jordan, Italy, Morocco, Egypt and India. Three gastropod species: Globularia sub-umbilicata, Ampullospira sp., Purpuroidea peristriata and seven bivalve species: Palaeonucula lateralis, Chlamys (Radulopecten) fibrosa, Eligmus weiri, E.integer, E. asiaticus, Musculus somaliensis and Pholadomya orientalis were recognized for the first time in the Lower Jurassic deposits of Saudi Arabia.
... The Callovian Tuwaiq Mountain Limestone Formation consists mainly of carbonate rocks and extends for more than 1200 km from south to north in central Saudi Arabia. In the subsurface the formation forms the major source-rock in the anoxic basins of the Middle East (Powers et al., 1966;Powers, 1968;Vaslet et al., 1983;Al Sharhan and Magara, 1995;El-Sorogy et al., 2014;Youssef and El-Sorogy, 2015). It was deposited on a carbonate platform developed across the intra-shelf basin (Ziegler, 2001). ...
Middle Jurassic (Callovian) strata of Tuwaiq Mountain Limestone Formation, central Saudi Arabia are
composed of thin- to thick-bedded, grainy and muddy limestones and dolostones with various skeletal
and nonskeletal components. Facies analysis documents low- to high-energy environments, including
lagoon, back reef, reef framework, fore-reef and intra-shelf basin lithofacies associations. Because of the
narrow lateral distribution of facies and the presence of distinctive fossils, the depositional system likely
represents an open marine shelf. Two third-order depositional sequences can be distinguished in the
stratigraphic measured section. Transgressive sequences show deepening-upward trends, in which
shallow water (lagoonal and back reef) facies are overlain by deeper-water (fore-reef and intra-shelf
basin) facies. Regressive sequences show shallowing-upward trends in which deep-water facies are
overlain by shallow-water facies. Most sequence boundaries in the study area are of the nonerosional
(SB2) type. Correlation of depositional sequences in the studied section reveals that relatively shallow
marine conditions predominated in the area.
... The stratigraphy and fossil content have been studied by many authors (e.g. Galal and Kamel, 2004;Hughes, 2004Hughes, , 2006Hughes, , 2008AL-Saad, 2008;El-Sorogy et al., 2014;Youssef and El-Sorogy, 2015;El-Sorogy and Al-Kahtany, 2015). ...
The Campanian Hajajah Limestone Member of the Aruma Formation was formed during two regressive episodes. Each of them formed of three depositional facies, from base to top: 1) intra-shelf basin facies, made up of fossiliferous green shale and mudstone with ostracods and badly preserved foraminifers. 2) fore-reef facies, consists of hard, massive, marly coralline limestone. The upper part is rich with low divers, badly to moderate preserved, solitary and colonial corals, and, 3) back reef and near-shore facies, consists of fossiliferous sandy dolomitized, bioturbated limestone with abundant reworked corals, bi-valves, gastropods, and aggregate grains. On the basis of field observations, micro-and macrofossils and microfacies analysis, the Hajajah Limestone Member was deposited in distal marine settings below storm wave base in a low-energy environment changed upward to fore-reef framework in an open marine environment with moderate to high energy conditions and terminated with shallow marine facies with accumulation of skeletal grains by storms during regression.
... The stratigraphy and fossil content have been studied by many authors (e.g. Galal and Kamel, 2004;Hughes, 2004Hughes, , 2006Hughes, , 2008AL-Saad, 2008;El-Sorogy et al., 2014;Youssef and El-Sorogy, 2015;El-Sorogy and Al-Kahtany, 2015). ...
This article deals with the Upper Jurassic carbonates of the Jubaila Formation, exposed throughout the Tuwaiq Mountains, Central Saudi Arabia and discusses the succession of palaeoenvironments resulting from detailed field and lab work. Based on microfacies analysis and sedimentological data, twelve facies are identified within the Upper Jurassic carbonates at Wadi Hanifa, Central Saudi Arabia. These facies are attributed to six main facies belts. Within these facies and facies belts, four distinct biofacies assemblages are recognized. Deposition took place on an extendable ramp, which probably dipped gently eastwards to the sea. A depositional model relates the identified facies and biofacies to a downdip depositional profile of an inner, middle and outer carbonate ramp. The burrowed lime mudstone and bioclastic wackestone-floatstone of facies belt 1 accumulated in a distal middle ramp to outer ramp. The mollusk-coated grains-intraclast rudstone of facies belt 2 were deposited in the distal middle ramp. The branched stromatoporoids Cladocoropsis were deposited in the proximal middle ramp of facies belt 3. The facies of the open lagoon (facies belt 5) and the tidal-flat (facies belt 6) were deposited in the inner ramp behind the ramp crest/shoal facies belt 4. The Early Kimmeridgian Jubaila Formation has been deposited as transgressive and highstand deposits of a third-order depositional sequence, which are mainly controlled by eustatic sea-level changes. During the transgression, an aggradational trend developed , with the construction of a deep subtidal facies of small-scale stacked cycles of mudstones with frequent mottled firm ground and hard ground, storm beds and tempestites. The regressive part has a characteristic progradational trend, with shallow-water carbonate platform deposits arranged into meter-scale coarsening-upward cycles ranged from dolomitic mudstone and wackestone to stromato-poroid packstone and rudstone into bioclastic intraclastic peloidal packstone and grainstone.
... The Callovian Tuwaiq Mountain Limestone Formation consists mainly of carbonate rocks and extends for more than 1200 km from south to north in central Saudi Arabia. In the subsurface the formation forms the major source-rock in the anoxic basins of the Middle East (Powers et al., 1966;Powers, 1968;Vaslet et al., 1983;Al Sharhan and Magara, 1995;El-Sorogy et al., 2014;Youssef and El-Sorogy, 2015). ...
To document the depositional architecture and sequence stratigraphy of the Upper Jurassic Hanifa Formation in central Saudi Arabia, three composite sections were examined, measured and thin section analysed at Al-Abakkayn, Sadous and Maashabah mountains. Fourteen microfacies types were identified, from wackestones to boundstones and which permits the recognition of five lithofacies associations in a carbonate platform. Lithofacies associations range from low energy, sponges, foraminifers and bioclastic burrowed offshoal deposits to moderate lithoclstic, peloidal and bioclastic foreshoal deposits in the lower part of the Hanifa while the upper part is dominated by corals, ooidal and peloidal high energy shoal deposits to moderate to low energy peloidal, stromatoporoids and other bioclastics back shoal deposits. The studied Hanifa Formation exhibits an obvious cyclicity, distinguishing from vertical variations in lithofacies types. These microfacies types are arranged in two third order sequences, the first sequence is equivalent to the lower part of the Hanifa Formation (Hawtah member) while the second one is equivalent to the upper part (Ulayyah member). Within these two sequences, there are three to six fourth-order high frequency sequences respectively in the studied sections.
... The Callovian Tuwaiq Mountain Limestone Formation consists mainly of carbonate rocks and extends for more than 1200 km from south to north in central Saudi Arabia. In the subsurface the formation forms the major source-rock in the anoxic basins of the Middle East (Powers et al., 1966;Powers, 1968;Vaslet et al., 1983;Al Sharhan and Magara, 1995;El-Sorogy et al., 2014;Youssef and El-Sorogy, 2015). It was deposited on a carbonate platform developed across the intra-shelf basin (Ziegler, 2001). ...
... The Callovian Tuwaiq Mountain Limestone Formation consists mainly of carbonate rocks and extends for more than 1200 km from south to north in central Saudi Arabia. In the subsurface the formation forms the major source-rock in the anoxic basins of the Middle East (Powers et al., 1966;Powers, 1968;Vaslet et al., 1983;Al Sharhan and Magara, 1995;El-Sorogy et al., 2014;Youssef and El-Sorogy, 2015). It was deposited on a carbonate platform developed across the intra-shelf basin (Ziegler, 2001). ...
... The Callovian Tuwaiq Mountain Limestone Formation consists mainly of carbonate rocks and extends for more than 1200 km from south to north in central Saudi Arabia. In the subsurface the formation forms the major source-rock in the anoxic basins of the Middle East (Powers et al., 1966;Powers, 1968;Vaslet et al., 1983;Al Sharhan and Magara, 1995;El-Sorogy et al., 2014;Youssef and El-Sorogy, 2015). It was deposited on a carbonate platform developed across the intra-shelf basin (Ziegler, 2001). ...
Middle Jurassic (Callovian) strata of Tuwaiq Mountain Limestone Formation, central Saudi Arabia are composed of thin- to thick-bedded, grainy and muddy limestones and dolostones with various skeletal and nonskeletal components. Facies analysis documents low- to high-energy environments, including lagoon, back reef, reef framework, fore-reef and intra-shelf basin lithofacies associations. Because of the narrow lateral distribution of facies and the presence of distinctive fossils, the depositional system likely represents an open marine shelf. Two third-order depositional sequences can be distinguished in the stratigraphic measured section. Transgressive sequences show deepening-upward trends, in which shallow water (lagoonal and back reef) facies are overlain by deeper-water (fore-reef and intra-shelf basin) facies. Regressive sequences show shallowing-upward trends in which deep-water facies are overlain by shallow-water facies. Most sequence boundaries in the study area are of the nonerosional (SB2) type. Correlation of depositional sequences in the studied section reveals that relatively shallow marine conditions predominated in the area.
... Most skeletal grains have rims of thin early-marine cement and micritization. The presence of these fossil assemblages suggests well oxygenated water with normal salinity in the open sea back-reef and shallow lagoon shelf ( Holzapfel, 1998;Sepkoski, 2002;Clark and Boudagher-Fadel, 2001;Ivanova et al., 2008;Neagu and Cirnaru, 2004;Masse et al., 2004;El-Sorogy et al., 2014;Youssef and El-Sorogy, 2015). Stromatoporoids requires moderately low energy conditions in order to avoid breakage, and are considered to have best developed in the distal part of the lagoon or in back banks, where the direct higher wave energy would be inhibited ( Hughes et al., 2009). ...
... The stratigraphy and fossil content have been studied by many authors (e.g. Galal and Kamel, 2004;Hughes, 2004Hughes, , 2006Hughes, , 2008AL-Saad, 2008;El-Sorogy et al., 2014;Youssef and El-Sorogy, 2015;El-Sorogy and Al-Kahtany, 2015). ...
This article deals with the Upper Jurassic carbonates of the Jubaila Formation, exposed throughout the Tuwiaq Mountains, Central Saudi Arabia and discusses the succession of palaeoenvironments resulting from detailed field and lab work. Based on microfacies analysis and sedimentological data, twelve facies are identified within the Upper Jurassic carbonates at Wadi Hanifa, central Saudi Arabia. These facies are attributed to six main facies belts. Within these facies and facies belts, four distinct biofacies assemblages are recognized. Deposition took place on an extendable ramp, which probably dipped gently eastwards to the sea. A depositional model relates the identified facies and biofacies to a downdip depositional profile of an inner, middle and outer carbonate ramp. The burrowed lime mudstone and bioclastic wackestone-floatstone of facies belt 1 accumulated in a distal middle ramp to outer ramp. The mollusk-coated grains-intraclast rudstone of facies belt 2 were deposited in the distal middle ramp. The branched stromatoporoids Cladocoropsis were deposited in the proximal middle ramp of facies belt 3. The facies of the open lagoon (facies belt 5) and the tidal-flat (facies belt 6) were deposited in the inner ramp behind the ramp crest/shoal facies belt 4. The Early Kimmeridgian Jubaila Formation has been deposited as transgressive and highstand deposits of a third-order depositional sequence, which are mainly controlled by eustatic sea-level changes. During the transgression, an aggradational trend developed, with the construction of a deep subtidal facies of small-scale stacked cycles of mudstones with frequent mottled firm ground and hard ground, storm beds and tempestites. The regressive part has a characteristic progradational trend, with shallow-water carbonate platform deposits arranged into metre-scale coarsening-upward cycles ranged from dolomitic mudstone and wackestone to stromatoporoid packstone and rudstone into bioclastic intraclastic peloidal packstone and grainstone.
The investigation mainly focuses on larger benthic foraminifera, Canalispina, Siderolites, Loftusia, and Omphalocyclus from the Maastrichtian deposits (Tarbur Formation) in the Zagros Foreland Basin. The four new species as Canalispina zagrosia sp. nov., Siderolites persica sp. nov., Loftusia tarburica sp. nov., and Omphalocyclus tarburensis sp. nov. and four other index species as Siderolites calcitrapoides, Omphalocyclus cideensis, O. macroporus, and Loftusia baykali were identified. L. harrisoni is thought to be ancestor of L. minor, L. arabica, L. matsumarui, L. tarburica sp. nov., L. occidentalis, L. coxi, L. baykali, L. kahtaensis and L. oktayi during the early, middle and late Maastrichtian, while L. persica and L. elongata evolved into L. arabica in the middle Maastrichtian. L. turcica and L. morgani are close forms of L. elongata in the middle and late Maastrichtian, and L. anatolica and L. morgani are the predominant forms in the late Maastrichtian. The wall structures of Loftusia species are more complex in the late Maastrichtian than in early Maastrichtian forms due to evolutionary trends. Loftusia species numerous whorls were predominant in the middle Maastrichtian. In contrast to this, the species with low whorl numbers during the early and late Maastrichtian were dominant. Detailed studies on Omphalocyclus species indicate that (1) the genus Omphalocyclus migrated from the middle part of Tethys to other Tethyan areas during the late Campanian, and (2) the diversity of Omphalocyclus species of eastern Tethys (North African part) was more than in other areas.
A major global marine transgression occurred during the Callovian to Early Kimmeridgian, which was interrupted locally by a hiatus during the Late Callovian to Early Oxfordian. The transgression may have been a major driver for extensive coral buildup development in the Oxfordian. The depositional hiatus may be related to a combination of eustasy, local tectonic activity and hinterland movements, highlighting the potential influence of tectonism on sedimentary evolution in sedimentary basins. Whilst a regional Late Callovian-Early Oxfordian hiatus has been recorded extensively in the Tethys realm, this study has improved the biostratigraphic and sedimentary record from Morocco, and for the first time documents the Late Callovian-Early Oxfordian depositional hiatus in the Atlantic realm. Detailed sedimentary facies analysis of Callovian to Oxfordian carbonates and siliciclastics (Ouanamane Formation) demonstrates a major transgression from continental and coastal sediments, through oolitic mid-inner ramp deposits, brachiopod-rich middle ramp deposits, and ultimately to outer ramp marls, sharply overlain by Middle Oxfordian coral buildups across the basin. Repeated hard- and firmgrounds and bioturbated bed tops highlight transgressive surfaces traceable basinwide, which suggests low sedimentation rates in the upper Ouanamane Formation. Localized siliciclastic input is evidence for episodes of erosion in the same interval. Collection of new fossil specimens (ammonites, brachiopods, echinoderms, foraminifera) and revision of existing fossil material suggest this interval corresponds to a hiatus or condensed section in the Callovian-Oxfordian transition. The uppermost part of the Ouanamane Formation is of early Middle Oxfordian age and is directly overlain by Middle Oxfordian coral buildups. Onset of buildup construction is considered synchronous based on the new biostratigraphic data. Observations in Moroco compare with the sedimentary evolution around the Tethys, and in particular with the Arabian Plate. The Callovian-Oxfordian depositional hiatus corresponds to eustatic sea level changes, which were possibly driven my global cooling, and was likely overprinted by local tectonics.
High nitrate and fluoride contamination in groundwater cause a variety of disorders, including methemoglobinemia, teratogenesis, and dental and skeletal fluorosis. The present work assesses the non-carcinogenic health risks posed by nitrate and fluoride in infants, children, and adults using the daily water intake (CDI), hazard quotient (HQ), and non-carcinogenic hazard index (HI). Groundwater samples were collected from 36 wells and boreholes in three central Saudi Arabian study areas for nitrate and fluoride analysis using ionic chromatography and fluoride selective electrode, respectively. Nitrate concentrations varied from 0.70 to 47.00 mg/L. None of the 36 studied boreholes had nitrate levels that exceeded WHO guidelines (50.00 mg/L). Fluoride ranged from 0.63 to 2.00 mg/L, and 30.55% of the fluoride samples (11 out of 36) exceeded the WHO recommendations for acceptable drinking water (1.5 mg/L). The average hazard index (HI) values for adults, children, and infants were 0.99, 2.59, and 2.77, respectively. Water samples surpassed the safety level of 1 for adults, children, and infants at 44.44, 97.22, and 100%, respectively. Accordingly, water samples from Jubailah and a few from Wadi Nisah may expose infants, children, and adults to non-cancer health concerns. Infants and children are more vulnerable to non-carcinogenic health risks than adults, possibly due to their lower body weight. Immediate attention and remedial measures must be implemented to protect residents from the adverse effects of F- in the study area.
In arid and semi-arid regions, freshwater is mainly acquired from groundwater. Over the years, human activities have reduced the latter’s quality, making it a threat to health. Heavy metal pollution index (HPI), metal index (MI), groundwater quality index (GWQI), sodium absorption ratio (SAR), magnesium ratio (MR), Kelly’s ratio (KR), and sodium percentage (Na%) were applied as pollution parameters and indices in assessing the groundwater’s suitability for irrigation and drinking purposes in Wadi Hanifa in Saudi Arabia. Samples were collected from 26 sites, and a physicochemical analysis and heavy metal analysis were conducted. The results showed a concentration of SO4²⁻, Cl–, Ca²⁺, HCO3⁻, Na⁺, Mg²⁺, and K⁺, which is higher than the WHO standards for drinking water. 96.15% of the water samples (n = 25) fell under the Ca–Cl groundwater dominant facies type, and one model fell under the mixed type. According to the GWQI classification, 16.66%, 50%, and 26.92% of the collected samples are categorized as very poor, poor, and generally unsuitable for human consumption, respectively. Parameters such as SAR, KR, and Na% are indicative of irrigation water. The study’s primary factors affecting the groundwater chemistry included the natural processes of precipitation or dissolution of the silicates, carbonates, and evaporites alongside anthropogenic activities and soil leaching.
The increasing availability of numerous journals with limited peer review and editorial standards has led to an ever-increasing introduction of new fossil taxa that ultimately need taxonomic revision. The introduction of dubious and poorly described taxa adds confusion to the scientific literature. Furthermore, their potential inclusion in global taxonomic databases, and the subsequent usage of this data in review papers necessitates critical comment and thoughtful clarification. The recent introduction of Siderolites jurassica Youssef & El-Sorogy is a good example of a taxon that is both poorly described and which clouds the literature, thus requiring revision. This species was described and illustrated from just one isolated specimen obtained from Callovian marls in Saudi Arabia. Siderolites represents an exclusively Upper Cretaceous (Campanian-Maastrichtian) complex rotaloid Large Benthic Foraminifera with a distinctive identity that can be clearly deciphered by studying oriented and random thin-sections. A Jurassic occurrence would overturn our current understanding of foraminiferal evolution as well as their usage for biostratigraphic analyses. It is suspected that the Middle Jurassic specimen described from Saudi Arabia belongs to small-sized group of arenaceous benthic foraminifera exhibiting conical protuberances (or spines) such as Thurammina Brady and should neither be regarded as belonging to the genus Siderolites nor any other siderolitid representative.
The present work aimed to evaluate the sources and ecological risks of heavy metal (HM) contamination in the soils of marine origin in central Saudi Arabia. HM concentrations were determined in 30 soil samples in October 2020, from Al Uyaynah–Al Jubailah region and their averages were in the following order: Al > Fe > Zn > Cr > Pb > Ni > As > Cu > Se > Cd > Hg > Sb. Average values of Zn, Ni, Co, Cr, and Cu in the investigated soils were less than averages of the continental crust, worldwide soils, and European soils, in contrast to the average values of As, Hg, Cd, and Se which were greater than the continental crust and worldwide soils. Enrichment factor, contamination factor, and degree of contamination revealed minor enriched and moderate contamination factors with As, Se, Hg, and Pb. Potential ecological risk index indicated that 93.33% of the soil samples fell under no-to-low risk, whereas 6.67% were categorized as moderate risk. Multivariate statistical analyses determined natural processes for Pb, Al, Cr, Sb, Zn, Fe, and Ni, while anthropogenic processes for As, Hg, and Se, mainly attributed to the chemicals used in agricultural applications and P fertilizers.
The groundwater quality and heavy metal (HM) contamination were evaluated in palm farms, central Saudi Arabia, using pollution indices, irrigation quality parameters, and multivariate statistical analyses. Thirty groundwater samples were collected in October 2020 for major anions, cations, and HMs analyses and interpretation. The results showed that the average concentrations of total dissolved solids (TDS), Ca+, Na+, K+, Cl−, SO42−, and F− were greater than the permissible limits of the WHO standards for drinking water. The groundwater facies types were Ca–Na–SO4–Cl (23 samples), Ca–Cl–SO4, (4 samples), and Ca–SO4–Cl type (3 samples). The groundwater quality index indicated that 15 groundwater samples were of good quality and 15 were of poor quality, whereas the metal index and heavy metal pollution index indicated that all samples were categorized as slightly affected and with low pollution, respectively. The variation is attributed to the increasing average concentrations of some ions and decreasing HMs. The dissolution/precipitation of silicates, gypsum, and carbonates and soil leaching were the natural factors affecting groundwater chemistry, whereas higher PO43−, NO3−, F−, Pb, and Zn values in some samples may be attributed to human activities from the extensive use of fertilizers and pesticides on the investigated farms.
The Upper Jurassic Jubaila Formation in central Saudi Arabia exhibits laterally coeval environments from the southwest to the northeast. These coeval environments involve inner, mid-, and outer ramps. The inner ramp occurs at the Al Haddar section in the extreme southwest and consists of mixed clastic-carbonate facies and are represented by intercalations of ferruginous calcareous quartz arenite, ferruginous sublitharenite, and burrowed dolomicrite. In the mid-ramp setting, there were changes from lateral facies in the Riyadh and the Wadi Huraymila areas to carbonates characterized by sandy lime-mudstones, dolosparie, peloidal olitic packstones, and coralline bioclastic wackestones to packstones. These are intercalated with sandy lime-mudstones that might be deposited in highly agitated environments. The outer-ramp setting occurred in the farther northeast Al Uyaynah area. It is characterized by reduced thickness and is composed of lime-mudstones, dolomitic marls, and pelletal bioclastic wackestones with thin beds of dolomitic marls. The lateral and vertical microfacies distribution in the Jubaila Formation are arranged vertically into four 3rd-order cycles that are correlate laterally overall the studied area, which are overprinted by oscillations in eustatic sea-level during the deposition of Jubaila Formation.
This chapter reviews the lithostratigraphy, biostratigraphy, age dating and sequence stratigraphy of the Arabian Intrashelf Basin to document the basic data used in the interpretations in this Memoir. The factors important to understanding these topics are discussed, including the typical facies, general depositional models, the effects of dolomitization, well log characteristics and the problems with obtaining precise age dates. Comments are included to show the interpretations preferred in this Memoir.
Satellite remote sensing is a popular method utilized in mineral and natural resource exploration, particularly to reduce reconnaissance and exploration costs. Its use is widely popular for geological mapping of arid regions. The primary objective of this paper is to illustrate how remote sensing satellite data could be used for mapping and assessing potential limestone raw material for the cement industry in Saudi Arabia. Limestone rocks are identified and mapped using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) indices, band combinations, band ratio combination, and relative absorption-band depth (RBD). Band combination of ASTER-thermal infrared (TIR) data 14:12:10, 8:6:1, and QI:CI:MI in R:G:B is also used for mapping limestone rocks with high efficiency as well as differentiating between sandstone and limestone rocks in the study area. Two band ratios 6/8 and 9/8 and RBD of (band 7+band 9)/band 8 are used for detecting limestone rocks as bright pixels. The carbonate index of ASTER-TIR data are subsequently used for mapping limestone areas and categorize them into classes for the purpose of using them as a raw material in the cement industry. Study findings show that high and very high classes of CI are concentrated in the southern and central parts of the study area such as Khashm Mazalij, Jabal Hit, and Jabal Hafafah and correlate with cement limestone and high-Ca limestone sites in the study area. Other very high limestone classes are found distributed in the northwestern part of Banban. Sulaiy Formation, in Khashm Mazalij area, also constitutes the best promising potential for high-purity limestone. It is hoped that the findings of the study provide ample evidence for the usefulness of the reconnaissance tool in assessing the limestone as raw materials, which is a vital process for the cement industry decision-makers in planning and managing natural resources in Saudi Arabia.
This paper provides the first record of isolated foraminiferal assemblages from the continuous Aalenian–lower Bajocian succession from the pelagic region of the Neotethys. The studied Tűzkövesárok section B of Bakonycsernye (Hungary) has been well dated by ammonites and consists of Ammonitico Rosso type limestones. The foraminiferal fauna extracted by glacial acetic acid yielded 49 benthic taxa (species and subspecies); protoglobigerinids also occurred. Most specimens belonged to the suborder Spirillinina, followed by the suborder Lagenina and Rotaliina; agglutinated forms were subordinate and miliolids were absent. The majority of the species have wide stratigraphic ranges; moreover, the distributions of 11 species changed based on their appearances in this section. Nevertheless, the Aalenian and Bajocian parts of the section could be distinguished based upon the stratigraphic distributions of some species.
Karst in interbedded carbonates and evaporites has been reported to have important and complex impacts on reservoir. It is significant for exploration and karst geology. Here, we report such a new case from Middle Triassic Leikoupo Formation of Sichuan Basin, Southwest China. Stratigraphic incompleteness and the occurrence of unconformity provide evidence for the presence of eogenetic karst. Under the impact of this eogenetic karst, residual weathered and solution-collapse breccia, solution pores and silicification and dedolomitization have been observed. Classic stratigraphic zonation of karst is not readily distinguishable, which is ascribed to the stratigraphic collapse of carbonate rocks resulting from the dissolution of evaporites by lateral subsurface fluid flow. In terms of impact on reservoir quality, karst can generally improve the initial physical property of the porous layers in theory. However, subsurface fluid flow dissolved the evarporitic beds and facilitated the collapse of overlying strata. As a consequence, the lateral continuity of the reservoirs would be destroyed, and relatively high-quality reservoirs can only be developed with little collapse of overlying strata, reflecting reservoir heterogeneities. This may be a general feature of reservoir formation under the impact of karst in interbedded carbonates and evaporites.
Beach rock, which forms at the intertidal zone, is a natural barrier to protect beach and island from wave erosion. The formation mechanism of beach rocks is significant in the study of surface carbonate diagenesis and protection of island. Beach rocks in Qilian Islets and Cays were formed about 500–700 a BP, neither its composition nor sedimentary structure experienced intense post-reformation. Beach rocks in Qilian Islets and Cays are mainly composed of reef-building skeletal fragments and bioclasts without terrigenous sediments. This study focused on the types and morphologies of cements in beach rocks of Qilian Islets and Cays, and its cementation mechanisms and influencing factors. Biological activities, such as micritization caused by microbial activities and algae binding action, play an important role in the initial stage of bioclast transformation and promote the subsequent early marine and early meteoric cementation. Acicular aragonite induced by early marine cementation is well developed in beach rocks, especially in those samples from Medium Islet. Early meteoric cementation is not common as marine cementation, generally presenting granular and meniscus cements. The main factors affecting the formation and development of beach rocks in Qilian Islets and Cays include sediment source, hydrodynamic condition, climate, sea level change and anthropogenic impacts.
The Jurassic succession in Saudi Arabia represents the most prolific succession in the world. However, a detailed microfacies and paleoenvironmental model description, high-frequency cycles (HFC) analysis, and paleoenvironmental reconstruction of the main source rock interval for the Jurassic reservoirs, the Callovian Tuwaiq Mountain Formation (TMF) are poorly documented. This article reports on a study of the TMF, and discusses the succession of the microfacies, paleoenvironments, HFC, and depositional sequences, and paleoenvironmental constrains. On the basis of detailed field and lab work, 8 microfacies were recognized and interpreted to be deposited in four facies belts representing the inner part of a rimmed carbonate platform including: deep lagoon, shallow lagoon, shoal and peritidal and tidal flat. Within the deep and shallow lagoonal settings, patch reefs form massive platy and domal coral colonies. The patch reef size increased by shifting from deep lagoon toward shallow lagoon settings as the conditions became more favorable for flourishing (harder substrate and more water clarity). While, by shifting from shallow lagoon to shoal settings, the patch reef size decreased till a point where no patch reefs were found as the conditions became unfavorable for flourishing (more restrictions and increase in salinity). The siliciclastic input was minute and could have been derived from tidal channels and/or windblown dust from the Arabian Shield. The stacking pattern of the microfacies revealed that the TMF represents a regressive cycle (3rd order depositional sequence), which is formed by repeated aggrading to prograding medium and small scale cycles. The HFC analysis gave an estimated duration of a small cycle about 45 Kyr. This drives to an average rate of carbonate accumulation of 0.0455 m/Kyr. Therefore, medium and small scale cycles are possibly belonging to 4th and 5th order depositional cycles, respectively, which are orbitally driven by high frequency eustatic fluctuations (Milankovitch cycles “obliquity”). The paleoenvironmental reconstruction revealed that the deposition occurred under the influence of occasional storm events with normal marine euhaline salinity and becomes more restricted towards the proximal part (lagoon to tidal flat).
The seventeen Jurassic species of Textulariacea which had been named by Redmond (1965), placed by him in his new genera Riyadhella and Pseudomarssonella, and which had been used by Aramco for biostratigraphy in Saudi Arabia, have been redescribed and are re-illustrated. The Chrysalidininae are not older than Cretaceous. Both the Paravalvulininae and the Chrysalidininae are referred to the Chrysalidinidae Neagu. They both contain specimens in which the micritic microgranules of the calcareous wall become aligned and may even be canaliculate. The taxonomic significance of canaliculi is discussed and it is concluded that the development of canaliculation is gradational and that their presence or absence cannot always be used to define supraspecific differences. The probable phylogenetic histories of the Chrysalidininae and the Paravalvulininae, and the biostratigraphic value of their genera, are discussed. -from Authors
The Jurassic sequence stratigraphic scheme for Central Saudi Arabia is extrapolated to the formations of the western and southern Arabian Gulf region resulting in a tentative chronostratigraphic framework. The framework is tentatively constrained as follows: (1) Upper Triassic-?Lower Jurassic continental clastics (Minjur and equivalents) and the subsequent pre-Toarcian unconformity indicate regional erosion and non-deposition over the Arabian platform. (2) A Toarcian sequence (Marrat and equivalents) provides a basal Jurassic regional datum, except in Oman. (3) The late Toarcian and Aalenian correspond to a substantial sea-level lowstand and a regional depositional hiatus. (4) The Middle Jurassic Dhruma Formation corresponds to four different sequences with a major intervening hiatus. The Upper Dhurma Member, together with the Tuwaiq Mountain form the topomost sequence. The correlation between the Dhruma, Tuwaiq Mountain, Hanifa and Jubaila formations, to their equivalents in other Arabian Gulf countries, requires clearer definitions. (5) The Arab and Hith Anhydrite formations are Tithonian based on their sequence assignment, while the Sulaiy Formation is Berriasian and straddles the Jurassic-Cretaceous bondary. (6) The four Tithonian Arab carbonates may have been deposited as transgressive and early highstand deposits. The Tithonian Arab, Gotnia and Hith anhydrites may be late highstand deposits which overstep inland 'salinas' (Gotnia and western Rub' Al-Khali). Each carbonate and overlying anhydrite sequence appear to correspond to a complete third-order cycle. (7) The equivalents to the Kimmeridgian Jubaila Formation and Tithonian Arab carbonates are absent by non-deposition in Kuwait. In Oman, the Arab and Hith Anhydrite formations are absent by erosion. (8) The Tithonian Hith Anhydrite provides a final Jurassic regional, stratigraphic datum, except in Oman and eastern United Arab Emirates.
The purpose of this note is to present revisions to the SP2 scheme resulting either from significant errors in SP2, or from newly published data that challenges SP2, or from newly published data identifying new maximum flooding surfaces.
The publication of Arabian Plate Sequence Stratigraphy (Sharland et al., 2001), commonly referred to as SP2, provided a unifying stratigraphic interpretation of the Arabian Plate within a modern sequence stratigraphic framework. In 2002 revisions to the stratigraphic positions of some SP2 Cretaceous maximum flooding surfaces (MFS), and some resulting new interpretations, were presented by Davies et al. (2002). New interpretations of mixed carbonate-clastic systems presented by these authors have application to other parts of Middle East stratigraphy.
Since 2001, many excellent new papers have been published, and oral presentations made, containing new data and/or interpretations (e.g. Al-Eidan et al., 2001; Brew et al., 2001; Konert et al., 2001; Ziegler, 2001; Al-Suwaidi and Aziz, 2002; Nehlig et al., 2002; van Buchem et al., 2002; Boote and Mou, 2003; Price and Fell, 2003; Stephenson et al., 2003 - to name but a few). The interpretations presented here are based on this new post-SP2 literature, as well as re-interpretations of older literature in the light of this new work.
Following discussions with Gulf PetroLink, the Ne.ex SP2 authors have been encouraged to provide a summary chronostratigraphic up-date based on this new literature for GEO 2004 of the SP2 interpretation, with particular emphasis on (1) revisions to the published geological timescale; (2) changes to SP2 megasequence boundaries (position and dating); (3) changes to SP2 maximum flooding surfaces (position and dating); (4) the identification and dating of any new TMS and/or MFS; and (5) any proposed changes to the SP2 sequence stratigraphic nomenclature.
This GeoArabia Stratigraphic Note and the accompanying two chronostratigraphic chart enclosures (Enclosure 1 Mesozoic and Cenozoic, and Enclosure 2 Palaeozoic and Precambrian), are intended to update those in SP2. These new charts have been extended into Jordan (in the north) and southwest Oman and Yemen (in the south). Significant changes to MFS are made in the Neogene, Palaeogene and Permo-Triassic sections.
Saudi Arabian Jurassic carbonate hydrocarbon reservoirs were first examined stratigraphically using microfauna. Current microfaunal studies concentrate on the identification and constraint of palaeoenvironmental variations and determination of high-resolution depositional cyclicity of the reservoir carbonates. It is apparent that the environmental sensitivity of benthonic foraminifera provides a potentially valuable technique for the determining subtle variations in the depositional environment and also providing a proxy for sea-level fluctuations.
Calcareous agglutinating foraminifera and other larger benthic foraminifera from two formations in central Lebanon confirm the presence of Late Jurassic and Early Cretaceous age carbonates below the continental Lower Cretaceous "basal sandstone". The lowermost formation, the Bikfaya Formation, is characterized by the presence of Buccicrenata sp., Alveosepta (Redmondellina) powersi (REDMOND), A. (A) jaccardi (SCHRODT), Pseudospirocyclina maynci HOTTINGER and Rectocyclammina chouberti HOTTINGER of Kimmeridgian age; while the overlying Salima Formation is characterized by Everticyclammina kelleri (HENSON), E. contorta REDMOND, Bramkampella arabica REDMOND and Riyadhella regularis REDMOND of Berriasian age. Trocholina alpina (LEUPOLD) and Nautiloculina oolithica Muhler and REICHEL are long-ranging species which occur throughout the Salima Formation, whereas Neotrocholina valdensis REICHEL of Berriasian - Valanginian age appears in the upper beds of the formation below the "basal sandstone". The resulting assemblage compares closely with taxa described from Iraq, the United Arab Emirates and Saudi Arabia, and confirms for the first time in central Lebanon a Kimmeridgian age for the basal 25 m of the Bikfaya Formation and a Berriasian-Valanginian age for the Salima Formation.
The oil producer Arab "D" unit in Qatar as well as in eastern Arabian Peninsula is composed of limestone and dolomitic limestone assigned to the Kimmeridgian age. In Qatar, this member reveals the presence of six rhythmic microfacies of mudstone (micrite), wackestone, dolomitic wackestone, packstone, grainstone and anhydrite. These sediments are believed to be deposited in numerous short-term transgressive-regressive cycles, but generally the Arab D member represents a regressive cycle. The grainstone facies in the middle part of the unit is rich in benthic foraminifera belonging to Kurnubia and Pfenderina. Palynological analysis yielded ecologically and biostratigraphically significant dinoflagellate cyst species such as Cribroperidinium globatum, C. longicorne, Dichadogonyaulax chondra, D. pannea, Epiploshaera bireticulata, Geochteodinia antennata, Systematophora areolata and S. penicillata, giving evidence for a late Kimmeridgian age of the Arab D member. Amorphous organic matter is the dominant element of the particulate organic matter. The Arab D member may have been deposited in shallow water of the middle shelf depth (30-50 m) under arid to semiarid climatic conditions as deduced from the presence of Classopollis pollen and the capping anhydrite.
Low-latitude carbonate platforms dominated the southern and northern margins and microplates of western Tethys during the
Early Jurassic. However, these have proved difficult to date in the past partly due to a lack of study but also a perception
of low biotic diversity following the Triassic-Jurassic extinction event. Detailed logging and sampling of seven continuously
exposed sections of Lower Jurassic shallow-marine carbonates in Gibraltar, Morocco, Tunisia, Greece, Italy, and in Spain reveals
the occurrence of 12 benthic foraminifera species. These taxa are described and illustrated, and include: one new speciesTextulariopsis sinemurensis, new records for the Early Jurassic, and new records for this region. Five new biozones for the late Hettangian to early
Pliensbachian time interval are erected from the consecutive appearance of benthic foraminifera within these sections, from
top to base:Lituosepta compressa, Lituosepta recoarensis, Everticyclammina praevirguliana, Siphovalvulina colomi andSiphovalvulina gibraltarensis. This has enabled the correlation of these sections for the first time from the northern and southern Tethys margins and
from the Apuleian and Pelagonian microplates within Tethys. The foraminiferal occurrences indicate a similarity of associations
from the southern and northern shallow carbonate shelves of Tethys, whilst reflecting the relative isolation of the Apuleian
and Pelagonian microplates within Tethys. The foraminifera show a progressive diversification of forms through the late Hettangian
to early Pliensbachian interval that is interpreted to reflect the evolutionary recovery and diversification of these biotas
following the Triassic-Jurassic extinction event.
The Arabian Gulf Middle Jurassic foraminiferal assemblage in Qatar and Saudi Arabia is compared with the known Middle Jurassic foraminiferal assemblages in Jordan and Egypt. In general, these faunas can be grouped into three broad assemblages, which can be related to three different palaeoenvironments. The three assemblages are recognized by variation of genera and species of the suborders Textulariina and Lagenina. The first assemblage is a carbonate platform assemblage which is distributed in the Arabian Gulf areas and is composed of 35 foraminiferal species, and restricted to an open platform environment. The second assemblage is of shallow to deep inner to middle clastic shelf environments that are located in north Egypt (Sinai and north Western Desert) and is composed of 89 foraminiferal species. The third assemblage represents a shoreline to shallow marine environment and has been recognized in Jordan and is composed of 42 foraminiferal species and considered to have been deposited in a shore environment shallower than that of north Egypt.
The Upper Jurassic sequence of the Aydincik (Içel) area consists of platform limestones which were deposited in a subtidal, restricted lagoon environment. Stratigraphic distribution of benthic foraminifera and calcareous algae, examined in thin-sections, is shown in a range-chart. The microfossil assemblage indicates the Salpingoporella sellii subzone of the Kurnubia palastiniensis cenozone, corresponding approximately to the lower part of the Malm. Some benthic foraminifera with considerable stratigraphic value within the Mesozoic Tethys are described. Among the benthic foraminifera, taxa of the family Pfenderinidae, especially the subfamily Kurnubiinae, are dominant and frequent throughout the sequence. The planispirally coiled taxa are represented by the families Nautiloculinidae, Charentiidae and Cyclamminidae (subfamily Bucciccrenatinae).
The primary location of this publication on ResearchGate is: https://www.researchgate.net/publication/279778628_Arabian_Plate_Sequence_Stratigraphy_GeoArabia
See linked data here for various chapters: https://www.researchgate.net/publication/279778628_Arabian_Plate_Sequence_Stratigraphy_GeoArabia
The Ar Riyad quadrangle is underlaid by Mesozoic to Cenozoic sedimentary rocks of the Arabian shelf, covered to a large extent by Quaternary deposits. Jurassic to Early Cretaceous rocks cropping out in the Ar Riyad area are assigned to the newly defined informal Dir'iyah supergroup, which consists of: 1) the Buraydah group, (Late Permian to Triassic) that crops out to the west of the quadrangle boundaries; 2) the informal Shaqra group and 3) the Thamama Group, comprising Early Cretaceous rocks. The Dir'yah supergroup is disconformably overlain by Late Cretaceous to Tertiary rocks. The Mesozoic-Cenozoic succession is characteristic of continental, littoral margin, or inner-shelf deposition, comprising transgressive and regressive phases alternating upward in the sequence. It is contained in a homocline dipping gently to the northeast and east. Mesozoic oil reservoirs are exploited in the Abu Jifan oil field in the northeast of the quadrangle. -from Authors
The earliest development of coral-bearing strata in Central Saudi Arabia took place during deposition of the Tuwaiq Mountain Limestone (upper Middle-Upper Callovian). It does not appear to constitute a major barrier reef, but rather a series of isolated corals and coral bioherms; coral heads (20-50 cm in diameter) are scattered in life position within an extensive sheet of pure limestone (20-40 m thick) stretching for more than 1000 km along strike in Central Saudi Arabia. This sheet could be described as an extensive biostrome. A striking feature of the Tuwaiq Mountain Limestone coral fauna is the low diversity of species that persisted throughout the development of the formation. A possible explanation for the low diversity of the fauna is inimical ecological conditions or palaeobiogeographical barriers which could have prevented the historical accumulation of species from neighbouring areas. Similar factors are responsible also for the endemism of the Jurassic Arabian fauna including ammonites, foraminifers, algae, ostracods, nautiloids, brachiopods and echinoids. -from Author
Volume 1 contains the text of the treatise, and volume 2, 847 plates. Of the 3620 validly proposed generic taxa of Foraminiferida considered 2455 genera are recognised, described and illustrated, 960 regarded as synonyms, 208 considered systematically unrecognisable, 16 too late for detailed inclusion. They are placed in 12 suborders, 74 superfamilies, 296 families, 302 subfamilies. A systematic index is included. The systematic arrangement of genera is alphabetical within the various subfamily or family categories, and the family group taxa within the suborders are arranged in order of presumed evolutionary sequence or increasing complexity. Descriptions are generally focused on test morphology, both external and internal, but some information concerning the living organism is summarized for the few that are known. Geologic range is given to the level of the geologic series of epoch, and known geographic occurrence and a limited amount of ecologic information is included. In view of the very large number of taxa considered, morphologic descriptions are as concise as possible, consistent with the inclusion of the available information. Morphologic terms used are defined in a glossary, in which reference also is given to other terms proposed by various writers. -from Authors
As early as 1959, Jan Muller appreciated that the distribution patterns of palynomorphs and other particulate organic matter (POM) could be used for facies recognition and palaeogeographic reconstruction (Muller 1959). Such applications, and the increasing use of palynological methods for assessing hydrocarbon source rock potential led to the development of the palynofacies concept. The term palynofacies was first introduced by Combaz in 1964 to describe the quantitative and qualitative palynological study of the total particulate organic matter assemblage. Palynofacies analysis involves the identification of individual palynomorph, plant debris, and amorphous components, their absolute and relative proportions, size spectra, and preservation states (Combaz 1964, 1980). Palynomorph colour estimation of the level of organic maturation was also included in the original concept, although this is now usually regarded as a somewhat separate and distinct field of study.
The study of the organic matter in sediments and sedimentary rocks focuses on the interaction between the biosphere and geosphere. A proper appreciation of the subject requires an understanding of the environmental controls which govern the production of organic matter in the biosphere, the ecological and sedimentological processes which control its deposition and distribution, the biogeochemical, and geomicrobiological factors which influence its preservation, and the geochemical and physical processes which determine its modification during its incorporation in the geosphere. This makes the study of sedimentary organic matter one of the most multidisciplinary pursuits within the whole field of earth sciences.
Three new genera and eighteen new species of foraminifera are described from the Jurassic of Saudi Arabia. Two of the genera, Pseudomarssonella and Riyadhella, are tentatively placed in Cushman's subfamily Globotextulariinae. The third, Dhrumella, can not be more closely placed than somewhere within the superfamily Rotaliacea.
Two new genera and eight new species of lituolid foraminifera from the Lower Cretaceous and Upper Jurassic of Saudi Arabia are described and figured. Two species of Pseudocyclammina occurring here develop Choffatella-like chambers in the microspheric generation. The term "minimal chamber" is suggested as a designation for such chambers, and the application of the concept to other genera is briefly discussed.
In this paper, 128 species of foraminifera and twelve species of holothuroid sclerites from Jurassic rocks out-crapping at Gebel Maghara, northern Sinai, are described and illustrated. Thirty-five species and two genera of foraminifera, and five holothuroid sclerites, are believed to be new. Sponge spicules from the Kimmeridgian are also illustrated but are not described. This study is primarily paleontological, but the stratigraphic value of these fossils is discussed, and the results of microfacies analyses of a number of indurated rocks in the succession are presented.
Investigation of well-preserved material from Saudi Arabia shows that the interior labyrinthine passages in the family Pfenderinidae Smout and Sugden, 1962, fall outside of rather than inside of the chamber cavities. The secondary infilling of the labyrinthine passages during the life of the individual, noted by Smout and Sugden as occurring among some members of the Pfenderinidae, is coupled with secondary deposition of shell material within the chamber cavities, and the presence or absence of these joint effects is taken as the basis for recognition of two-new subfamilies, the Pfenderininae and the Kurnubiinae. The formation of subcameral tunnels is discussed, and four new genera and ten new species of the Pfenderinidae are described from the Jurassic of Saudi Arabia.
The Jurassic system as developed along a strike of some 500 miles in the Jebel Tuwaiq, central Saudi Arabia (Nejd), is described and divided into formations, of which the names are here published for the first time, with a synopsis of their lithology and fossil contents. Apart from small collections, including only one ammonite species, made on camel journeys by H. St J. B. Philby, nothing was hitherto known of these formations; their age (except for the Middle Callovian date given by the ammonite), and the existence of most of them, were unknown until the area began to be mapped and explored geologically about 1940 by geologists of the Arabian American Oil Company, whose results are here summarized. The total thickness of marine Jurassic rocks described exceeds 1000 m., all of it in neritic facies. This sequence is divided, in ascending order, into Marrat, Dhruma, Tuwaiq Mountain, Hanifa, Jubaila and Riyadh formations, above which follows the Cretaceous system. Below the marine Marrat is the Minjur Sandstone (315 m.), of 'continental' facies, with only obscure plant remains, which possibly corresponds to the supposedly Rhaetic-Lower Lias plant-bearing Kohlan Sandstones of the Yemen. The underlying Jilh formation of Saudi Arabia contains marine Middle Triassic fossils near the top. Collections of ammonites establish the presence of marine Jurassic stages from Lower Toarcian (Lower Marrat) to Lower Kimeridgian (Jubaila); the Riyadh has not yet yielded ammonites at outcrop. The ammonites described are of extraordinary interest from the points of view of palaeogeography, correlation, phylogeny and systematics. While most of the faunas contain just enough links with other parts of the world to establish broad correlations, many are entirely new, or confined, outside Arabia, to Sinai. In the Toarcian there was faunal continuity with Madagascar and Baluchistan, in the Bajocian only with Sinai, from the Middle Bathonian onwards with western Europe. Most of the commonest cosmopolitan genera are missing from central Arabia, where there lived a succession of highly peculiar forms characterized at several successive horizons by unstable suture-lines. It has been found necessary to make eight new genera, besides three already named but hitherto not found outside Sinai, Madagascar and Baluchistan, although employing a taxonomic scale so large that some palaeontologists will consider it old-fashioned. This is believed, however, to be more useful at this stage of our knowledge than a proliferation of generic names based on inadequate material; for the area from which the collections were made is about equal to that of all the Jurassic outcrops of England. The paper concludes with a discussion of problems of evolution, speciation, correlation, and palaeogeography raised by the material. In an appendix are described relevant Bajocian ammonites from Sinai, with a hitherto unpublished section of the strata.
While studying foraminefera from the Tertiary of Iraq and Iran, which had been referred to in literature under the name of Archaias aduncus (Fichtel and Moll), the author concluded that the structure of these organisms does not conform to the description of Archaias [ Orbiculina ] given by W. B. Carpenter ( Phil. Trans. Roy. Soc. , Vol. 146, 1856, part II, pp. 547–52, pl. xxviii, figs. 1-16; pl. xxix, figs. 1-3) and generally accepted in standard text-books on the Foraminefera (Galloway 1933; Cushman 1940; Glaessner 1945). According to these authors, Archaias may be described as a large, compressed Peneroplis sometimes becoming cyclical in the later stages, and with the primary chambers sub-divided into rectangular chamberlets by transverse secondary septa. In specimens from Iraq and Iran, however, sections parallel to the equatorial plane but very near the lateral surfaces of the test showed no subdivision of the primary chambers.
Following up this observation, sections were cut through the primary chambers in directions normal to given radii of the discoidal shell; and these preparations showed clearly that the internal structures traversing the primary chambers are not secondary septa, but pillars normal to the primary septa. The pillars are numerous and alternate in position with small perforations (apertures) through the primary septa
The question immediately arose whether these Middle Eastern forms should be assigned to a new genus or whether Carpenter's description is erroneous.
It was thought that a distinction might be found between Recent and Tertiary forms attributed from localities in the Caribbean region and
Benthic foraminiferal distribution patterns in the Lower Jurassic Rotzo Member (Trento Platform, northeastern Italy) are analysed in terms of trophic gradients to provide a better understanding of the benthic communities during the time of the initial diversification of Lower Jurassic large foraminifera in the Southern Alps. The Rotzo Member deposited on the Trento Platform records a complex mosaic of distinct shallow water ecosystems. The changes in the foraminiferal assemblages of the Rotzo Member are considered to be primarily a reflection of gradients in trophic resources and oxygen levels.
A recent review (Haman, 1988) of the publication “Foraminiferal Genera and Their Classification” by Alfred R. Loeblich, Jr. and Helen Tappan, Van Nostrand Reinhold Company, New York, incorrectly indicated the date of its publication as “early 1988,” although adding, parenthetically, “The senior author refers to the publication date as December, 1987, A. R. Loeblich, Jr., January, 1988, written communication.”
Foraminifera and Brackish Ostracoda from the Portlandian of Polish Lowlands
- W Bielecka
Bielecka, W., 1975. Foraminifera and Brackish Ostracoda from
the Portlandian of Polish Lowlands. Acta Paleontologica
Polonica, 20(3): 295-393
Pfenderina gracilis Riyadhella paraconica Levina Riyadhella regularis Redmond
- Pfender Pfenderina
Pfenderina neocomiensis Pfender; 14. Pfenderina gracilis; 15. Riyadhella paraconica Levina; 16. Riyadhella regularis
Redmond; 17. Riyadhoides mcclurei Redmond.
Trophic Regimes of Benthic Foraminiferal Assemblages in Lower Jurassic Shallow Water Carbonates from Northeastern Italy (Calcari Grigi
- A Fogagnoli
Fogagnoli, A., 2004. Trophic Regimes of Benthic Foraminiferal Assemblages in Lower Jurassic Shallow Water Carbonates from Northeastern Italy (Calcari Grigi, Trento
Platform,
Venetian
Prealps).
Re-Examination of the Morphology of Nautiloculina circularis (Said and Barakat) 1959 from the Upper Jurassic of Egypt and Israel
- P Bronnimann
Bronnimann, P., 1968. Re-Examination of the Morphology of
Nautiloculina circularis (Said and Barakat) 1959 from
the Upper Jurassic of Egypt and Israel. C. R. Seances,
SPHN, 2(1): 62-73
- Fourcade
1985 Nautiloculina circularis (Said and Barakat)-Fourcade et
al., Pl. 3, Fig. 4.
2001 Nautiloculina circularis (Said and Barakat)-Tasli, p. 3,
Pl. 1, Fig. 1.
Testacea Britannica or Natural History of British Shells, Marine, Land, and Fresh-water, Including the Most Minute: Systematically Arranged and Embellished with Figures
- G Montagu
Montagu, G., 1803. Testacea Britannica or Natural History of
British Shells, Marine, Land, and Fresh-water, Including
the Most Minute: Systematically Arranged and Embellished with Figures. J. White, London, 2: 293-606
New Information on the Foraminiferal
- A H Smout
- W Sugden
Smout, A. H., Sugden, W., 1962. New Information on the Foraminiferal Genus. Pfenderina. Paleontology, 4(4):
581-591
Le Associazioni a Foraminiferi Bentonici del Giurassico Inferiore de Ua Piattaforma di Trento (Calcari Grigi-Liassico)
- A Fugagnoli
Fugagnoli, A., 1998. Le Associazioni a Foraminiferi Bentonici
del Giurassico Inferiore de Ua Piattaforma di Trento
(Calcari Grigi-Liassico). Sistematica, Biostratigrafia e
Paleoecologia. Dottorato di Ricerca in Scienze della Terra.
Habitat of Oil. American Association of Petroleum Geologists
- M Steineke
- R A Bramkamp
- N J Sanders
Steineke, M., Bramkamp, R. A., Sanders, N. J., 1958. Stratigraphic Relations of Arabian Jurassic Oil. In: Weeks, L.
G., ed., Habitat of Oil. American Association of Petroleum Geologists, Tulsa. 1294-1329
- R Said
- M G Barakat
Said, R., Barakat, M. G., 1959. Jurassic Microfossils from Gebel Maghara, Sinai, Egypt. Micropaleontology, 4(3):
231–271
Stratigrafiya i Korrelyatsiya Verkhnei Yury po Foraminiferam
- A A Grigelis
Grigelis, A. A., 1985. Stratigrafiya i Korrelyatsiya Verkhnei
Yury po Foraminiferam. Moscow. 1-104 (in Russian)