Reflection seismic data acquired for hydrocarbon exploration in Saudi Arabia have revealed five buried crater structures ranging in diameter from 5 km to 34 km. These structures have little or no present-day surface expression and span a range of ages from Ordovician to Cenozoic. The Saqqar structure (29°35′N, 38°42″E) is 34 km in diameter and is formed in Devonian siliciclastics. The structure is partially eroded and is unconformably overlain by Upper Cretaceous and Paleogene strata up to 400 m thick. The Jalamid structure (31°27′N, 39°35″E) is 19 km in diameter at Lower Ordovician level and is infilled by Middle Ordovician sediments, at a present-day depth of 4,500 m. The Banat Baqar structure (29°07′N, 37°36″E) is 12 km in diameter at Middle Ordovician level and infilled by Upper Ordovician sediments, at a depth of 2,000 m. The Hamidan structure (20°36′N, 54°44″E) is 16 km in diameter at Paleogene level and is overlain by a thin veneer of Recent sediment. The Zaynan structure (20°23′N, 50°08″E) is 5 km in diameter and affects Triassic sediments at depth of 3,800 m, and is infilled by Jurassic strata. In addition to reflection seismic imaging, various amounts of gravity and magnetic data and drilled wells are available in or near these structures. Various models including impact cratering are discussed here for each structure. One structure (Saqqar) has yielded quartz grains with possible shock metamorphic features that, contingent on future work, may support a meteorite impact crater interpretation.
{"title":"Five buried crater structures imaged on reflection seismic data in Saudi Arabia","authors":"A. S. Neville, D. Cook, A. Afifi, S. Stewart","doi":"10.2113/geoarabia190117","DOIUrl":"https://doi.org/10.2113/geoarabia190117","url":null,"abstract":"\u0000 Reflection seismic data acquired for hydrocarbon exploration in Saudi Arabia have revealed five buried crater structures ranging in diameter from 5 km to 34 km. These structures have little or no present-day surface expression and span a range of ages from Ordovician to Cenozoic. The Saqqar structure (29°35′N, 38°42″E) is 34 km in diameter and is formed in Devonian siliciclastics. The structure is partially eroded and is unconformably overlain by Upper Cretaceous and Paleogene strata up to 400 m thick. The Jalamid structure (31°27′N, 39°35″E) is 19 km in diameter at Lower Ordovician level and is infilled by Middle Ordovician sediments, at a present-day depth of 4,500 m. The Banat Baqar structure (29°07′N, 37°36″E) is 12 km in diameter at Middle Ordovician level and infilled by Upper Ordovician sediments, at a depth of 2,000 m. The Hamidan structure (20°36′N, 54°44″E) is 16 km in diameter at Paleogene level and is overlain by a thin veneer of Recent sediment. The Zaynan structure (20°23′N, 50°08″E) is 5 km in diameter and affects Triassic sediments at depth of 3,800 m, and is infilled by Jurassic strata. In addition to reflection seismic imaging, various amounts of gravity and magnetic data and drilled wells are available in or near these structures. Various models including impact cratering are discussed here for each structure. One structure (Saqqar) has yielded quartz grains with possible shock metamorphic features that, contingent on future work, may support a meteorite impact crater interpretation.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-01-01DOI: 10.2113/geoarabia1901117
Mohammad Alqudah, M. Hussein, O. Podlaha, S. V. D. Boorn, S. Kolonic, J. Mutterlose
Cretaceous and Paleogene marls, rich in total organic carbon, are widespread throughout Jordan and adjoining areas. Based on planktonic foraminifera these oil shales have been assigned a late Campanian–Paleocene age in previous studies. For the current analysis a total of 283 smear slides from five wells in central Jordan have been investigated for calcareous nannofossil biostratigraphy. Findings suggest a much more differentiated age model of the oil shales than previously proposed. The oil shales studied contain abundant calcareous nannofossil taxa of Eocene age along with varying abundances of Maastrichtian and Paleocene taxa. The encountered marker species Rhomboaster cuspis, Tribrachiatus bramlettei, Tribrachiatus orthostylus, Discoaster lodoensis, Coccolithus crassus, Discoaster sublodoensis, Nannotetrina quadrata, Reticulofenestra umbilicus and Chiasmolithus solitus, indicate an Early to Middle Eocene age, while the presence of Maastrichtian and Paleocene forms suggests major reworking. The presence of Cretaceous taxa reflects either subaerial erosive input from the hinterland or submarine reworking of Cretaceous strata within the basin. The highly variable amount of reworked material and associated deposition rates in the basin may represent changes in the tectonic setting during the Eocene. We propose that the high abundances of Cretaceous and Paleocene taxa reflect an increase in accommodation space by active graben flank movements. A dominance of Eocene taxa, on the other hand, indicates either periods of little accommodation space due to graben infill or inversion-type movements of the graben itself. In any case, the youngest Eocene and autochthonous taxa represent shallower or low topography graben phases.
{"title":"Calcareous nannofossil biostratigraphy of Eocene oil shales from central Jordan","authors":"Mohammad Alqudah, M. Hussein, O. Podlaha, S. V. D. Boorn, S. Kolonic, J. Mutterlose","doi":"10.2113/geoarabia1901117","DOIUrl":"https://doi.org/10.2113/geoarabia1901117","url":null,"abstract":"\u0000 Cretaceous and Paleogene marls, rich in total organic carbon, are widespread throughout Jordan and adjoining areas. Based on planktonic foraminifera these oil shales have been assigned a late Campanian–Paleocene age in previous studies. For the current analysis a total of 283 smear slides from five wells in central Jordan have been investigated for calcareous nannofossil biostratigraphy. Findings suggest a much more differentiated age model of the oil shales than previously proposed. The oil shales studied contain abundant calcareous nannofossil taxa of Eocene age along with varying abundances of Maastrichtian and Paleocene taxa. The encountered marker species Rhomboaster cuspis, Tribrachiatus bramlettei, Tribrachiatus orthostylus, Discoaster lodoensis, Coccolithus crassus, Discoaster sublodoensis, Nannotetrina quadrata, Reticulofenestra umbilicus and Chiasmolithus solitus, indicate an Early to Middle Eocene age, while the presence of Maastrichtian and Paleocene forms suggests major reworking. The presence of Cretaceous taxa reflects either subaerial erosive input from the hinterland or submarine reworking of Cretaceous strata within the basin. The highly variable amount of reworked material and associated deposition rates in the basin may represent changes in the tectonic setting during the Eocene. We propose that the high abundances of Cretaceous and Paleocene taxa reflect an increase in accommodation space by active graben flank movements. A dominance of Eocene taxa, on the other hand, indicates either periods of little accommodation space due to graben infill or inversion-type movements of the graben itself. In any case, the youngest Eocene and autochthonous taxa represent shallower or low topography graben phases.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-10-01DOI: 10.2113/geoarabia1804137
H. E. Atfy, R. Brocke, D. Uhl
Palynological results of a detailed study carried out on 56 samples retrieved from two selected wells (GH 404-2A and SA-E6A) of the Hilal and Shoab Ali fields within the southern part of the Gulf of Suez, Egypt, are presented. This study is mainly focused on the poorly dated Nukhul Formation, for which very little information from palynology is available despite its importance from a petroleum viewpoint. The assemblages discovered in our study are moderately preserved and reveal a sparse but significant record of spores and pollen and dinoflagellates together with highly diverse fungi and algal taxa, e.g. Botryococcus and Pediastrum. A latest Oligocene–Early Miocene (Chattian–Aquitanian) age has been suggested for the Nukhul Formation, based on compiling palynostratigraphic and ecologic data obtained from palynomorphs that have previously been assumed to be representatives for this period on a regional scale. In addition, the Oligocene/Miocene Boundary (OMB) could be lithostratigraphically defined within the studied formation, most likely at the boundary between the lower Shoab Ali Member and upper Ghara Member. A fungal/algal ‘event’ within the interval from 11,370–11,430 ft in the GH 404-2A Well may be associated with a strong regressive phase. Such a regression was previously observed in the Nile Delta and other locations around the Red Sea province, and may be assigned to the global Mi-1 glaciation event at the OMB. However, not only glacial-driven eustacy but also tectonic activity related to the Gulf of Suez rifting may have contributed in forming such an event. Palynofacies investigations were carried out under both transmitted and fluorescence microscopy and the results were partly supplemented by existing organic geochemical analyses (GH 404-2A Well) involving Rock-Eval pyrolysis and total organic carbon (TOC) measurements. The analysis was used to interpret the depositional regime, paleoenvironment and thermal maturation history of the studied succession. These results support the temporary existence of shallow, pond- or lake-like aquatic habitats during deposition of the lower Shoab Ali Member that evolved into a shallow-marine environment with the onset of the deposition of upper Ghara Member of the Nukhul Formation.
{"title":"Age and paleoenvironment of the Nukhul Formation, Gulf of Suez, Egypt: Insights from palynology, palynofacies and organic geochemistry","authors":"H. E. Atfy, R. Brocke, D. Uhl","doi":"10.2113/geoarabia1804137","DOIUrl":"https://doi.org/10.2113/geoarabia1804137","url":null,"abstract":"\u0000 Palynological results of a detailed study carried out on 56 samples retrieved from two selected wells (GH 404-2A and SA-E6A) of the Hilal and Shoab Ali fields within the southern part of the Gulf of Suez, Egypt, are presented. This study is mainly focused on the poorly dated Nukhul Formation, for which very little information from palynology is available despite its importance from a petroleum viewpoint. The assemblages discovered in our study are moderately preserved and reveal a sparse but significant record of spores and pollen and dinoflagellates together with highly diverse fungi and algal taxa, e.g. Botryococcus and Pediastrum.\u0000 A latest Oligocene–Early Miocene (Chattian–Aquitanian) age has been suggested for the Nukhul Formation, based on compiling palynostratigraphic and ecologic data obtained from palynomorphs that have previously been assumed to be representatives for this period on a regional scale. In addition, the Oligocene/Miocene Boundary (OMB) could be lithostratigraphically defined within the studied formation, most likely at the boundary between the lower Shoab Ali Member and upper Ghara Member. A fungal/algal ‘event’ within the interval from 11,370–11,430 ft in the GH 404-2A Well may be associated with a strong regressive phase. Such a regression was previously observed in the Nile Delta and other locations around the Red Sea province, and may be assigned to the global Mi-1 glaciation event at the OMB. However, not only glacial-driven eustacy but also tectonic activity related to the Gulf of Suez rifting may have contributed in forming such an event.\u0000 Palynofacies investigations were carried out under both transmitted and fluorescence microscopy and the results were partly supplemented by existing organic geochemical analyses (GH 404-2A Well) involving Rock-Eval pyrolysis and total organic carbon (TOC) measurements. The analysis was used to interpret the depositional regime, paleoenvironment and thermal maturation history of the studied succession. These results support the temporary existence of shallow, pond- or lake-like aquatic habitats during deposition of the lower Shoab Ali Member that evolved into a shallow-marine environment with the onset of the deposition of upper Ghara Member of the Nukhul Formation.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-10-01DOI: 10.2113/geoarabia1804179
L. Walz, T. Aigner, B. Koehrer
The Khuff Formation is a major producer of non-associated gas and an exploration target in the Middle East. The Middle Permian to Lower Triassic Khuff carbonates were deposited on a gently inclined epeiric carbonate ramp, which formed on the margin of the Neo-Tethys Ocean. The formation represents a supersequence consisting of transgressive-regressive sequences KS6 to KS1 from oldest to youngest. This paper focuses on a detailed sedimentological analysis of Khuff Sequence KS5 in outcrops in Al Jabal al-Akhdar in the Oman Mountains, Sultanate of Oman. Based on the sedimentological analysis of five outcrop sections, 11 facies types were identified in KS5. These were grouped into six facies associations, which represent environments ranging from a tidal flat to offshoal. Based on the 1-D analysis of sequences and their stacking patterns, 2-D correlations were constructed on a scale of several tens of kilometers. These correlations were used to build the framework for 3-D facies models. In contrast to the typical “layer-cake”-type Upper Khuff sequences KS4 to KS1 in terms of facies associations and cyclicity prominent lateral facies association changes and thickness variations are common in KS5, which makes correlation challenging. Different correlation strategies were tested, all resulting in complex cycle and stratal geometries with cycle pinch-outs and apparent cycle set downlaps/onlaps. Due to the dynamic depositional changes throughout KS5, the lateral extent of shoal-associated grainstones is limited. The appearance of these potential reservoir bodies is mainly governed by paleogeography and stratigraphic position. The observed depositional patterns represent significant variations from a rather simple “layer-cake”-type stratigraphic architecture and are possibly due to effects of differential subsidence on a subregional scale. This study contributes to a more detailed understanding of the Lower Khuff’s reservoir distribution and continuity, which is a key to ensuring future success in Khuff exploration and the efficient recovery in producing fields.
Khuff组是非伴生气的主要产地，也是中东地区的勘探目标。中二叠统—下三叠统Khuff碳酸盐岩沉积在新特提斯洋边缘形成的缓倾斜表状碳酸盐岩斜坡上。该地层是由KS6 ~ KS1由最老到最年轻的海侵-海退序列组成的超序。本文对阿曼山区Al Jabal Al - akhdar露头的Khuff层序KS5进行了详细的沉积学分析。通过对5个露头剖面的沉积学分析，确定了KS5的11种相类型。它们被分为六个相组合，代表了从潮滩到近海的环境。在对序列及其叠加模式进行一维分析的基础上，构建了几十公里尺度上的二维关联关系。这些相关性被用来构建三维相模型的框架。与典型的“层饼”型上胡夫层序KS4 ~ KS1相组合和旋回性不同，KS5普遍存在显著的侧向相组合变化和厚度变化，这给对比带来了挑战。测试了不同的相关策略，所有这些策略都导致了复杂的周期和地层几何形状，包括周期掐灭和明显的周期集下接/上接。由于整个KS5的动态沉积变化，浅滩伴生颗粒岩的侧向范围有限。这些潜在储层的出现主要受古地理和地层位置的支配。观察到的沉积模式与相当简单的“层饼”型地层结构有很大的不同，可能是由于分区域尺度上的差异沉降的影响。该研究有助于更详细地了解下Khuff的储层分布和连续性，这是确保未来Khuff勘探成功和生产油田高效采收率的关键。
{"title":"Khuff Sequence KS5 outcrop-equivalents in the Oman Mountains, Sultanate of Oman: Variations to the simple “layer-cake” stratigraphy","authors":"L. Walz, T. Aigner, B. Koehrer","doi":"10.2113/geoarabia1804179","DOIUrl":"https://doi.org/10.2113/geoarabia1804179","url":null,"abstract":"\u0000 The Khuff Formation is a major producer of non-associated gas and an exploration target in the Middle East. The Middle Permian to Lower Triassic Khuff carbonates were deposited on a gently inclined epeiric carbonate ramp, which formed on the margin of the Neo-Tethys Ocean. The formation represents a supersequence consisting of transgressive-regressive sequences KS6 to KS1 from oldest to youngest. This paper focuses on a detailed sedimentological analysis of Khuff Sequence KS5 in outcrops in Al Jabal al-Akhdar in the Oman Mountains, Sultanate of Oman. Based on the sedimentological analysis of five outcrop sections, 11 facies types were identified in KS5. These were grouped into six facies associations, which represent environments ranging from a tidal flat to offshoal. Based on the 1-D analysis of sequences and their stacking patterns, 2-D correlations were constructed on a scale of several tens of kilometers. These correlations were used to build the framework for 3-D facies models.\u0000 In contrast to the typical “layer-cake”-type Upper Khuff sequences KS4 to KS1 in terms of facies associations and cyclicity prominent lateral facies association changes and thickness variations are common in KS5, which makes correlation challenging. Different correlation strategies were tested, all resulting in complex cycle and stratal geometries with cycle pinch-outs and apparent cycle set downlaps/onlaps. Due to the dynamic depositional changes throughout KS5, the lateral extent of shoal-associated grainstones is limited. The appearance of these potential reservoir bodies is mainly governed by paleogeography and stratigraphic position. The observed depositional patterns represent significant variations from a rather simple “layer-cake”-type stratigraphic architecture and are possibly due to effects of differential subsidence on a subregional scale. This study contributes to a more detailed understanding of the Lower Khuff’s reservoir distribution and continuity, which is a key to ensuring future success in Khuff exploration and the efficient recovery in producing fields.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68185946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study is part of a large-scale outcrop analog study on Middle Permian to Lower Triassic Khuff-equivalent strata in the Oman Mountains, Al Jabal al-Akhdar, Sultanate of Oman. The Khuff outcrop equivalent can be divided into six sequences (Khuff sequences KS6 to KS1, from base to top). The main focus of this study is the description of the internal anatomy of the shoal grainstone bodies in the lower part of Sequence KS4 (“lower KS4”). High-resolution sedimentological logging of three outcrop sections in wadis Sahtan, Bani Awf and Mistal yielded eight lithofacies types that were grouped into five facies associations. Lower KS4 strata were mainly deposited within a “shoal complex” of an epeiric carbonate ramp, resulting in a thick pile of up to 70 m of grainstones that, on first sight, appear relatively homogeneous. However, detailed facies and microfacies analysis revealed their heterogeneous architecture on various scales: (1) Minor changes in depositional environments directly affected the type of carbonate grains (ooids versus peloids/cortoids versus bioclasts), leading potentially to highly variable pore systems (moldic versus interparticle versus intraparticle). (2) Vertically, detailed sequence-stratigraphic analysis revealed a higher-order of cyclicity (“mini-cycles”) on a decimeter- to meter-scale. Four mini-cycle types were recognized. (3) Laterally, facies changes, the amalgamation of grainstone beds and mini-cycle pinch-outs were observed in 2-D correlations on a scale of a few kilometers. These different types of heterogeneities may contribute to varying production rates commonly observed in the subsurface KS4 reservoir.
本研究是阿曼苏丹国Al Jabal Al - akhdar地区阿曼山脉中二叠统至下三叠统赫夫等效地层大规模露头模拟研究的一部分。Khuff露头等效层序可划分为6个层序(Khuff层序KS6 ~ KS1，自下而上)。本研究的重点是对KS4层序下部浅滩粒岩体的内部解剖进行描述(“下KS4”)。对wadis Sahtan、Bani Awf和Mistal的三个露头剖面进行了高分辨率沉积学测井，得到了8种岩相类型，分为5种岩相组合。KS4下部地层主要沉积在一个表相碳酸盐斜坡的“浅滩复群”中，形成了一堆厚达70米的颗粒岩，乍一看，这些颗粒岩相对均匀。沉积环境的微小变化直接影响了碳酸盐颗粒的类型(鲕状颗粒vs球粒状/皮质状颗粒vs生物碎屑)，从而可能导致高度变化的孔隙系统(模塑型、粒间型和粒内型)。(2)在纵向上，详细的层序地层分析揭示了分米至米尺度的高旋回性(“小旋回”)。确定了四种小周期类型。(3)横向上，在几公里尺度的二维相关上，观察到相变化、颗粒岩层合并和小旋回尖灭。这些不同类型的非均质性可能导致KS4地下储层中常见的不同产量。
{"title":"High-resolution anatomy of a grainstone package in Khuff Sequence KS4, Oman Mountains, Sultanate of Oman","authors":"M. Haase, T. Aigner","doi":"10.2113/geoarabia180417","DOIUrl":"https://doi.org/10.2113/geoarabia180417","url":null,"abstract":"\u0000 This study is part of a large-scale outcrop analog study on Middle Permian to Lower Triassic Khuff-equivalent strata in the Oman Mountains, Al Jabal al-Akhdar, Sultanate of Oman. The Khuff outcrop equivalent can be divided into six sequences (Khuff sequences KS6 to KS1, from base to top). The main focus of this study is the description of the internal anatomy of the shoal grainstone bodies in the lower part of Sequence KS4 (“lower KS4”). High-resolution sedimentological logging of three outcrop sections in wadis Sahtan, Bani Awf and Mistal yielded eight lithofacies types that were grouped into five facies associations. Lower KS4 strata were mainly deposited within a “shoal complex” of an epeiric carbonate ramp, resulting in a thick pile of up to 70 m of grainstones that, on first sight, appear relatively homogeneous. However, detailed facies and microfacies analysis revealed their heterogeneous architecture on various scales: (1) Minor changes in depositional environments directly affected the type of carbonate grains (ooids versus peloids/cortoids versus bioclasts), leading potentially to highly variable pore systems (moldic versus interparticle versus intraparticle). (2) Vertically, detailed sequence-stratigraphic analysis revealed a higher-order of cyclicity (“mini-cycles”) on a decimeter- to meter-scale. Four mini-cycle types were recognized. (3) Laterally, facies changes, the amalgamation of grainstone beds and mini-cycle pinch-outs were observed in 2-D correlations on a scale of a few kilometers. These different types of heterogeneities may contribute to varying production rates commonly observed in the subsurface KS4 reservoir.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"63 2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The predominantly carbonate Aptian–Lower Turonian succession of the Coastal Range in northwest Syria represents the northern edge of the Levant Platform. It was divided into 28 lithostratigraphic units, mainly reflecting shallowing-up and deepening-up intervals. We combined lithostratigraphy, biostratigraphy and carbon-isotope measurements, with facies interpretations, to establish a sequence-stratigraphic framework, adapted from outcrop data along two transects. The sequence-stratigraphic evolution records major transgressions-regressions and hiatuses that are compared with regional sequences of the Arabian and Levant platforms and the Tethyan realm. Age control, based on planktonic and benthonic foraminifera and ammonite biostratigraphies, is relatively good, despite changing diversities and occurrences. The chronostratigraphic framework is based on seven benthonic foraminiferal biozones (Aptian to Early Turonian) and six planktonic foraminiferal biozones (with two subzones) (latest Albian to Cenomanian). The studied carbon-isotope fluctuations record significant perturbations that are comparable with several global changes of the carbon cycle: OAE1d, LCE I-III, MCE and OAE2. The combined chemostratigraphic and biostratigraphic approach permits correlating the carbon-isotope curve of the Coastal Range with those from the Tethyan realm, England and South Palmyrides.
{"title":"Stratigraphic control of the Aptian–Early Turonian sequences of the Levant Platform, Coastal Range, northwest Syria","authors":"H. Ghanem, J. Kuss","doi":"10.2113/geoarabia180485","DOIUrl":"https://doi.org/10.2113/geoarabia180485","url":null,"abstract":"\u0000 The predominantly carbonate Aptian–Lower Turonian succession of the Coastal Range in northwest Syria represents the northern edge of the Levant Platform. It was divided into 28 lithostratigraphic units, mainly reflecting shallowing-up and deepening-up intervals. We combined lithostratigraphy, biostratigraphy and carbon-isotope measurements, with facies interpretations, to establish a sequence-stratigraphic framework, adapted from outcrop data along two transects. The sequence-stratigraphic evolution records major transgressions-regressions and hiatuses that are compared with regional sequences of the Arabian and Levant platforms and the Tethyan realm. Age control, based on planktonic and benthonic foraminifera and ammonite biostratigraphies, is relatively good, despite changing diversities and occurrences. The chronostratigraphic framework is based on seven benthonic foraminiferal biozones (Aptian to Early Turonian) and six planktonic foraminiferal biozones (with two subzones) (latest Albian to Cenomanian). The studied carbon-isotope fluctuations record significant perturbations that are comparable with several global changes of the carbon cycle: OAE1d, LCE I-III, MCE and OAE2. The combined chemostratigraphic and biostratigraphic approach permits correlating the carbon-isotope curve of the Coastal Range with those from the Tethyan realm, England and South Palmyrides.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Zohdi, reza Mousavi-Harami, S. Moallemi, A. Mahboubi, A. Immenhauser
We document and discuss the results of detailed fieldwork, facies analysis and the subsequent integration of paleoecological evidence from the Middle Eocene carbonate ramp succession in the southeast Zagros Basin (Jahrum Formation). A combination of a sea-level fall and tectonic and diapiric basement uplift favored the initiation of the Jahrum carbonate platform. The lower portions are affected by pervasive, probably early diagenetic dolomitization, whilst the upper Jahrum consists mainly of limestone. Here, the focus is on the limestone portions of the Jahrum Formation. Based on the abundance, diversity and rapid evolutionary turnover of the alveolinids and nummulitids, the limestone intervals of the Jahrum Formation are interpreted for the upper Middle Eocene (Bartonian). The Jahrum Formation is capped by a major unconformity and overlain by the Lower Oligocene mixed clastic/carbonate Razak Formation. Based on data from field sections, eight facies associations and a series of sub-types have been established, which correspond to inner-, middle-and outer-ramp depositional environments. In their overall context, these data show a southward-dipping inner-ramp-to-basin transect. Towards the Coastal Fars (e.g. Hulur-01 Well) the Jahrum grades laterally into deep-marine Pabdeh foredeep shale units. Based on facies analysis and paleoecological evidence from larger benthic foraminifera, a major transgressive-regressive pattern is recognized in all outcrop sections of the Jahrum. The lowermost stratigraphic units of the formation are here interpreted as a distally steepened ramp. Evidence comes from abundant allochthonous shallow-water facies in the distal, deeper-ramp setting. Shallow-water carbonate clasts were exported towards the basin, a feature that is probably linked to relative sea-level fall control. Furthermore, local to regional basement instabilities by salt diapir-related basement reorganization was arguably of significance. Upsection, evidence is found that the ramp system evolved from a distally steepened to a homoclinal geometry with an overall very gentle slope geometry during the Late Bartonian. The data shown here are significant for those concerned with the Paleogene evolution of the southeast Zagros Basin and provide a well-exposed case example of a Middle Eocene carbonate ramp factory.
{"title":"Evolution, paleoecology and sequence architecture of an Eocene carbonate ramp, southeast Zagros Basin, Iran","authors":"A. Zohdi, reza Mousavi-Harami, S. Moallemi, A. Mahboubi, A. Immenhauser","doi":"10.2113/geoarabia180449","DOIUrl":"https://doi.org/10.2113/geoarabia180449","url":null,"abstract":"\u0000 We document and discuss the results of detailed fieldwork, facies analysis and the subsequent integration of paleoecological evidence from the Middle Eocene carbonate ramp succession in the southeast Zagros Basin (Jahrum Formation). A combination of a sea-level fall and tectonic and diapiric basement uplift favored the initiation of the Jahrum carbonate platform. The lower portions are affected by pervasive, probably early diagenetic dolomitization, whilst the upper Jahrum consists mainly of limestone. Here, the focus is on the limestone portions of the Jahrum Formation. Based on the abundance, diversity and rapid evolutionary turnover of the alveolinids and nummulitids, the limestone intervals of the Jahrum Formation are interpreted for the upper Middle Eocene (Bartonian). The Jahrum Formation is capped by a major unconformity and overlain by the Lower Oligocene mixed clastic/carbonate Razak Formation.\u0000 Based on data from field sections, eight facies associations and a series of sub-types have been established, which correspond to inner-, middle-and outer-ramp depositional environments. In their overall context, these data show a southward-dipping inner-ramp-to-basin transect. Towards the Coastal Fars (e.g. Hulur-01 Well) the Jahrum grades laterally into deep-marine Pabdeh foredeep shale units. Based on facies analysis and paleoecological evidence from larger benthic foraminifera, a major transgressive-regressive pattern is recognized in all outcrop sections of the Jahrum. The lowermost stratigraphic units of the formation are here interpreted as a distally steepened ramp. Evidence comes from abundant allochthonous shallow-water facies in the distal, deeper-ramp setting. Shallow-water carbonate clasts were exported towards the basin, a feature that is probably linked to relative sea-level fall control. Furthermore, local to regional basement instabilities by salt diapir-related basement reorganization was arguably of significance. Upsection, evidence is found that the ramp system evolved from a distally steepened to a homoclinal geometry with an overall very gentle slope geometry during the Late Bartonian.\u0000 The data shown here are significant for those concerned with the Paleogene evolution of the southeast Zagros Basin and provide a well-exposed case example of a Middle Eocene carbonate ramp factory.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A series of lithofacies associations are defined for the Permian Umm Irna Formation indicating deposition in a fluvial regime characterised by low-sinuosity channels with deposition on point bars, and as stacked small-scale braided channels. Umm Irna Formation floodplain interfluves were characterised by low-energy sheet-flood deposits, shallow lakes and ponds, and peaty mires. Floodplain sediments, where not waterlogged, are generally pedogenically altered red-beds with ferralitic palaeosols, indicating a fluctuating groundwater table and humid to semi-arid climate. The Dead Sea outcrop provides a field analogue for similar fluvial and paralic depositional environments described for the upper Gharif Formation alluvial plain ‘Type Environment P2’ in the subsurface in Oman and the upper the basal clastics of the Khuff Formation at outcrop and in the subsurface in Central Saudi Arabia. Coarse-grained clasts within channel sandstones are mineralogically immature; their palaeocurrent directions and new evidence of glaciogenic sediments from Central Saudi Arabia suggests derivation from Pennsylvanian–Early Permian glaciofluvial outwash sandstones located to the east-southeast. The palynology of the Umm Irna Formation is remarkably varied. Samples from argillaceous beds of fluvial origin appear to contain a palynomorph representation of the wider hinterland of the drainage basin of the river including floodplain plants and more distant communities. In restricted water bodies like oxbow lakes or other impermanent stagnant floodplain ponds and peaty mires (immature coals), a higher proportion of purely local palynomorphs appear to be preserved in associated sediments. One of the assemblages representing local plant communities displays a Cathaysian palaeophytographic affinity, while others from similar levels within the Umm Irna Formation present a Gondwanan affinity. This indicates the risk of generalisation from single borehole or limited outcrop studies. The presence of Protohaploxypinus uttingii suggests an age range of Wordian–Capitanian to early Wuchiapingian (Middle to early Late Permian) for the Umm Irna Formation. The quantitative character of the Umm Irna Formation assemblages is very close to those of the basal Khuff clastics in the Central Saudi Arabian wells Dilam-1, Nuayyim-2 and Haradh-51. The lithological character and palynology of the transition between the Sa’ad and Arqov formations in the West Bank, west of the Dead Sea are similar to those of the transition between the Umm Irna Formation and overlying Ma’in Formation in Jordan.
{"title":"Palynology and alluvial architecture in the Permian Umm Irna Formation, Dead Sea, Jordan","authors":"M. Stephenson, J. Powell","doi":"10.2113/geoarabia180317","DOIUrl":"https://doi.org/10.2113/geoarabia180317","url":null,"abstract":"\u0000 A series of lithofacies associations are defined for the Permian Umm Irna Formation indicating deposition in a fluvial regime characterised by low-sinuosity channels with deposition on point bars, and as stacked small-scale braided channels. Umm Irna Formation floodplain interfluves were characterised by low-energy sheet-flood deposits, shallow lakes and ponds, and peaty mires. Floodplain sediments, where not waterlogged, are generally pedogenically altered red-beds with ferralitic palaeosols, indicating a fluctuating groundwater table and humid to semi-arid climate. The Dead Sea outcrop provides a field analogue for similar fluvial and paralic depositional environments described for the upper Gharif Formation alluvial plain ‘Type Environment P2’ in the subsurface in Oman and the upper the basal clastics of the Khuff Formation at outcrop and in the subsurface in Central Saudi Arabia. Coarse-grained clasts within channel sandstones are mineralogically immature; their palaeocurrent directions and new evidence of glaciogenic sediments from Central Saudi Arabia suggests derivation from Pennsylvanian–Early Permian glaciofluvial outwash sandstones located to the east-southeast.\u0000 The palynology of the Umm Irna Formation is remarkably varied. Samples from argillaceous beds of fluvial origin appear to contain a palynomorph representation of the wider hinterland of the drainage basin of the river including floodplain plants and more distant communities. In restricted water bodies like oxbow lakes or other impermanent stagnant floodplain ponds and peaty mires (immature coals), a higher proportion of purely local palynomorphs appear to be preserved in associated sediments. One of the assemblages representing local plant communities displays a Cathaysian palaeophytographic affinity, while others from similar levels within the Umm Irna Formation present a Gondwanan affinity. This indicates the risk of generalisation from single borehole or limited outcrop studies.\u0000 The presence of Protohaploxypinus uttingii suggests an age range of Wordian–Capitanian to early Wuchiapingian (Middle to early Late Permian) for the Umm Irna Formation. The quantitative character of the Umm Irna Formation assemblages is very close to those of the basal Khuff clastics in the Central Saudi Arabian wells Dilam-1, Nuayyim-2 and Haradh-51. The lithological character and palynology of the transition between the Sa’ad and Arqov formations in the West Bank, west of the Dead Sea are similar to those of the transition between the Umm Irna Formation and overlying Ma’in Formation in Jordan.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2013-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68186184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-07-01DOI: 10.2113/geoarabia1803103
M. Al-Husseini, B. Koehrer
The Middle Permian (Guadalupian), Upper Permian (Lopingian) and Lower Triassic Khuff and correlative formations in the Arabian Plate consist of six “third-order” sequences, from oldest to youngest KS6 to KS1, and at least 45 “fourth-order” sequences. They are here dated using biostratigraphic constraints and correlated to two independent sequence-stratigraphic time scales: (1) global sequences calibrated in the Geological Time Scale GTS 2012; and (2) orbital-forcing glacio-eustatic sequences that track the 0.405 million year (Myr) orbital eccentricity signal in the M&H-2010 scale (Matthews and Al-Husseini, 2010). The chronostratigraphic calibration of the Khuff sequences provides a reference section and common nomenclature that can be used for regional and global correlations. It permits positioning the hydrocarbon reservoirs of the Khuff and equivalent formations in a sequence-stratigraphic framework that can be used in exploration and reservoir characterization. The lower sequence boundary of the Khuff Formation (Khuff SB) is correlated to global Wordian SB Wor1 near the Roadian/Wordian Boundary at 268.8 ± 0.5 Ma, and correlative SB 19C at 268.9 Ma in the M&H-2010 scale. The upper sequence boundary of the Khuff Formation with the overlying Sudair Formation (Sudair SB) is correlated to Olenekian SB Ole1 near the Induan/Olenekian Boundary at 250.0 ± 0.5 Ma, and correlative SB 17 at 249.5 Ma in the M&H-2010 scale. These calibrations imply the Khuff was deposited in about 19.4 Myr, and consists of 48 “stratons”; i.e. transgressive-regressive (T-R) depositional subsequences with an average duration of 0.405 Myr corresponding to long-eccentricity orbital cycles 664 to 617. The 48 stratons are predicted to form four “dozons” (19C, 18A, 18B and 18C), each consisting of 12 stratons. Individual dozons lasted 4.86 Myr and are separated by regional sequence boundaries (SB 19C to SB 17A). In Oman, Khuff Sequence KS6 on the Saiq Plateau is correlated to the subsurface Lower Khuff Member, and both are interpreted to consist of 12 subsequences that are correlated to stratons 664–653 forming Dozon 19C between 268.9–264.0 Ma. KS6 is correlated to the four global sequences Wordian Wor1 to Capitanian Cap1 dated between 268.8–264.0 Ma in GTS 2012. Khuff Sequence KS5 corresponds to the Middle Khuff Member up to the top of Middle Khuff Anhydrite in subsurface Oman. On the Saiq Plateau, KS5 potentially consists of 12 cycle sets (Koehrer et al., 2010) that are correlated to stratons 652–641 of Dozon 18A, between 264.0–259.2 Ma. It is correlated to global sequences Capitanian Cap2 and Cap3 dated between 264.0–259.8 Ma in GTS 2012. Khuff Sequence KS4 consists of 11 cycle sets on the Saiq Plateau and other localities in Al Jabal al-Akhdar in Oman (Koehrer et al., 2010, 2012). It is assumed that one cycle set remains unidentified in KS4, completing its correlation to stratons 640–629 of Dozon 18B between 259.2–254.3 Ma. KS4 correlates to the global sequences Wuchiaping
{"title":"Chrono- and sequence-stratigraphy of the Mid-Permian to Early Triassic Khuff sequences of the Arabian Plate","authors":"M. Al-Husseini, B. Koehrer","doi":"10.2113/geoarabia1803103","DOIUrl":"https://doi.org/10.2113/geoarabia1803103","url":null,"abstract":"\u0000 The Middle Permian (Guadalupian), Upper Permian (Lopingian) and Lower Triassic Khuff and correlative formations in the Arabian Plate consist of six “third-order” sequences, from oldest to youngest KS6 to KS1, and at least 45 “fourth-order” sequences. They are here dated using biostratigraphic constraints and correlated to two independent sequence-stratigraphic time scales: (1) global sequences calibrated in the Geological Time Scale GTS 2012; and (2) orbital-forcing glacio-eustatic sequences that track the 0.405 million year (Myr) orbital eccentricity signal in the M&H-2010 scale (Matthews and Al-Husseini, 2010). The chronostratigraphic calibration of the Khuff sequences provides a reference section and common nomenclature that can be used for regional and global correlations. It permits positioning the hydrocarbon reservoirs of the Khuff and equivalent formations in a sequence-stratigraphic framework that can be used in exploration and reservoir characterization.\u0000 The lower sequence boundary of the Khuff Formation (Khuff SB) is correlated to global Wordian SB Wor1 near the Roadian/Wordian Boundary at 268.8 ± 0.5 Ma, and correlative SB 19C at 268.9 Ma in the M&H-2010 scale. The upper sequence boundary of the Khuff Formation with the overlying Sudair Formation (Sudair SB) is correlated to Olenekian SB Ole1 near the Induan/Olenekian Boundary at 250.0 ± 0.5 Ma, and correlative SB 17 at 249.5 Ma in the M&H-2010 scale. These calibrations imply the Khuff was deposited in about 19.4 Myr, and consists of 48 “stratons”; i.e. transgressive-regressive (T-R) depositional subsequences with an average duration of 0.405 Myr corresponding to long-eccentricity orbital cycles 664 to 617. The 48 stratons are predicted to form four “dozons” (19C, 18A, 18B and 18C), each consisting of 12 stratons. Individual dozons lasted 4.86 Myr and are separated by regional sequence boundaries (SB 19C to SB 17A).\u0000 In Oman, Khuff Sequence KS6 on the Saiq Plateau is correlated to the subsurface Lower Khuff Member, and both are interpreted to consist of 12 subsequences that are correlated to stratons 664–653 forming Dozon 19C between 268.9–264.0 Ma. KS6 is correlated to the four global sequences Wordian Wor1 to Capitanian Cap1 dated between 268.8–264.0 Ma in GTS 2012. Khuff Sequence KS5 corresponds to the Middle Khuff Member up to the top of Middle Khuff Anhydrite in subsurface Oman. On the Saiq Plateau, KS5 potentially consists of 12 cycle sets (Koehrer et al., 2010) that are correlated to stratons 652–641 of Dozon 18A, between 264.0–259.2 Ma. It is correlated to global sequences Capitanian Cap2 and Cap3 dated between 264.0–259.8 Ma in GTS 2012. Khuff Sequence KS4 consists of 11 cycle sets on the Saiq Plateau and other localities in Al Jabal al-Akhdar in Oman (Koehrer et al., 2010, 2012). It is assumed that one cycle set remains unidentified in KS4, completing its correlation to stratons 640–629 of Dozon 18B between 259.2–254.3 Ma. KS4 correlates to the global sequences Wuchiaping","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2013-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68185443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The δ13C values of Albian to Cenomanian shallow-marine carbonate sequences of the Natih Formation have been collected from subsurface cores of a key location in Oman. The 450-m-thick stack of shelf carbonates is without significant gaps in deposition. The δ13C data range between 1‰ and 6‰, more-or-less tracking the evolution over time of δ13C in seawater established elsewhere in time-equivalent pelagic carbonate sequences. Anchored by biostratigraphy the isotope profile suggests several additional time correlations. It thus provides significantly enhanced stratigraphic resolution and a key section for regional correlations. In particular, the onset of Natih deposition (Natih F and G members) coincides with the Albian/Cenomanian boundary event, thus placing the base Natih into the Albian. The Natih C and D members were deposited mainly during the Mid-Cenomanian oceanic anoxic event, while the carbon-isotopes signature of the Natih A Member, which is at this locality incomplete due to erosion, documents the onset of the Cenomanian/Turonian boundary event (OAE2). This indicates a latest Cenomanian, possibly Early Turonian age for the top Natih at this subsurface location and suggests an Early Turonian age for the more complete Natih section exposed in the nearby Oman Mountains sections. Both organic-rich intervals of the Natih Formation (Natih E4b and B2) do not correlate with global Oceanic Anoxic Events indicating a rather local setting for source-rock deposition. This is further supported by an isotopic anomaly associated with the organic-rich Natih B. The anomaly is likely related to near-seabed diagenesis or a temporary limited water exchange of the intra-shelf basin with the open ocean and the incorporation of recycled carbon from oxidized organic matter into the water column and the inorganic carbon pool. The subsurface carbon-isotope profile correlates well with those from nearby outcrop and other subsurface sections adding further confidence that primary signatures are preserved and can be used for correlations. As in other Early Cretaceous shelf sequences of the Arabian Plate oxygen isotopes are lighter than expected for calcite deposited in equilibrium with Cretaceous seawater indicating most likely whole-scale recrystallization and stabilization during shallow burial at slightly elevated temperatures.
{"title":"Carbon-isotope signatures of Albian to Cenomanian (Cretaceous) shelf carbonates of the Natih Formation, Sultanate of Oman","authors":"V. Vahrenkamp","doi":"10.2113/geoarabia180365","DOIUrl":"https://doi.org/10.2113/geoarabia180365","url":null,"abstract":"\u0000 The δ13C values of Albian to Cenomanian shallow-marine carbonate sequences of the Natih Formation have been collected from subsurface cores of a key location in Oman. The 450-m-thick stack of shelf carbonates is without significant gaps in deposition. The δ13C data range between 1‰ and 6‰, more-or-less tracking the evolution over time of δ13C in seawater established elsewhere in time-equivalent pelagic carbonate sequences. Anchored by biostratigraphy the isotope profile suggests several additional time correlations. It thus provides significantly enhanced stratigraphic resolution and a key section for regional correlations. In particular, the onset of Natih deposition (Natih F and G members) coincides with the Albian/Cenomanian boundary event, thus placing the base Natih into the Albian. The Natih C and D members were deposited mainly during the Mid-Cenomanian oceanic anoxic event, while the carbon-isotopes signature of the Natih A Member, which is at this locality incomplete due to erosion, documents the onset of the Cenomanian/Turonian boundary event (OAE2). This indicates a latest Cenomanian, possibly Early Turonian age for the top Natih at this subsurface location and suggests an Early Turonian age for the more complete Natih section exposed in the nearby Oman Mountains sections.\u0000 Both organic-rich intervals of the Natih Formation (Natih E4b and B2) do not correlate with global Oceanic Anoxic Events indicating a rather local setting for source-rock deposition. This is further supported by an isotopic anomaly associated with the organic-rich Natih B. The anomaly is likely related to near-seabed diagenesis or a temporary limited water exchange of the intra-shelf basin with the open ocean and the incorporation of recycled carbon from oxidized organic matter into the water column and the inorganic carbon pool. The subsurface carbon-isotope profile correlates well with those from nearby outcrop and other subsurface sections adding further confidence that primary signatures are preserved and can be used for correlations. As in other Early Cretaceous shelf sequences of the Arabian Plate oxygen isotopes are lighter than expected for calcite deposited in equilibrium with Cretaceous seawater indicating most likely whole-scale recrystallization and stabilization during shallow burial at slightly elevated temperatures.","PeriodicalId":55118,"journal":{"name":"Geoarabia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2013-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68185968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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