Devapriya Chattopadhyay, K. Venu Gopal, Avinash Dahakey
The Cenozoic evolution of the Tethyan seaway significantly shaped marine and terrestrial biota around Eurasia. The Tethys connected the Atlantic and the Pacific during the early Cenozoic, allowing marine faunal exchange. However, during the Early Miocene, the “ Gomphotherium Landbridge” developed, restricting the marine connection between the proto-Mediterranean in the west and the provinces in the eastern Tethys. In contrast to the well-documented phenomena of terrestrial mammalian exchange through the land connection brought by the closure, little is known about its impact on marine fauna. To assess the overall effect of this separation on the distribution and diversity of marine organisms, we studied the Oligo-Miocene fossil record of marine benthos including Cnidaria, Echinodermata, Foraminifera, and Mollusca. We compiled 15894 reported occurrences from the Early Oligocene to Late Miocene comprising 1477genera, 404 families, and 85 orders from four faunal provinces and evaluated their paleobiogeographic patterns. Our study demonstrates that the proportion of genera shared between the eastern and western provinces decreased after the Early Miocene. The majority of the non-shared family developed during or after the Early Miocene. A high faunal diversity during the Early Miocene and increasing endemicity among the eastern province are consistent with the development of a shallow seaway that supported speciation and reduced biotic exchange. The considerable variation in the magnitude and timing of the response across taxonomic groups reflect the combined effects of preservation bias, and the differential response of fauna. Our study supports an Early Miocene initiation of the Tethyan seaway closure, followed by intermittent connectivity before the complete closure that shaped the overall diversity and distribution of the Eurasian marine benthos. Supplementary material at https://doi.org/10.6084/m9.figshare.c.7266388
{"title":"The effect of the Tethyan seaway closure on the Oligo-Miocene marine benthic diversity and distribution around Eurasia","authors":"Devapriya Chattopadhyay, K. Venu Gopal, Avinash Dahakey","doi":"10.1144/sp549-2023-165","DOIUrl":"https://doi.org/10.1144/sp549-2023-165","url":null,"abstract":"\u0000 \u0000 The Cenozoic evolution of the Tethyan seaway significantly shaped marine and terrestrial biota around Eurasia. The Tethys connected the Atlantic and the Pacific during the early Cenozoic, allowing marine faunal exchange. However, during the Early Miocene, the “\u0000 Gomphotherium\u0000 Landbridge” developed, restricting the marine connection between the proto-Mediterranean in the west and the provinces in the eastern Tethys. In contrast to the well-documented phenomena of terrestrial mammalian exchange through the land connection brought by the closure, little is known about its impact on marine fauna. To assess the overall effect of this separation on the distribution and diversity of marine organisms, we studied the Oligo-Miocene fossil record of marine benthos including Cnidaria, Echinodermata, Foraminifera, and Mollusca. We compiled 15894 reported occurrences from the Early Oligocene to Late Miocene comprising 1477genera, 404 families, and 85 orders from four faunal provinces and evaluated their paleobiogeographic patterns. Our study demonstrates that the proportion of genera shared between the eastern and western provinces decreased after the Early Miocene. The majority of the non-shared family developed during or after the Early Miocene. A high faunal diversity during the Early Miocene and increasing endemicity among the eastern province are consistent with the development of a shallow seaway that supported speciation and reduced biotic exchange. The considerable variation in the magnitude and timing of the response across taxonomic groups reflect the combined effects of preservation bias, and the differential response of fauna. Our study supports an Early Miocene initiation of the Tethyan seaway closure, followed by intermittent connectivity before the complete closure that shaped the overall diversity and distribution of the Eurasian marine benthos.\u0000 \u0000 \u0000 Supplementary material at\u0000 https://doi.org/10.6084/m9.figshare.c.7266388\u0000","PeriodicalId":281618,"journal":{"name":"Geological Society, London, Special Publications","volume":"6 16","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141380638","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}
R. Venkatachalapathy, L. Harini, M. B. Hart, Watkinson M. P.
The Cauvery Basin is an important rift margin basin on the east coast of India. It's long research history began in the mid-nineteenth century with the pioneering work of H.F. Blanford. While much of the Cretaceous succession in the basin is fault-controlled, some of the recorded events represent global sea level changes, especially in the mid-Cretaceous. Macrofossils (ammonites, bivalves, etc. ) and foraminifera are abundant throughout, and there is an important occurrence of fossil wood and ‘log-grounds’ in the Turonian-Coniacian. The basin is sub-divided into a series of sub-basins (known as depressions in the earlier literature) which - in places - have their own distinctive depositional history. The results of our collective fieldwork have provided a re-assessment of the lithostratigraphy, biostratigraphy and the tectono-stratigraphical history of the Ariyalur outcrop. Three sedimentary units have been identified; the syn-rift Gondwana Group (of early Cretaceous age), the syn-rift Uttatur Group (of Albian to Coniacian age) and the post-rift Ariyalur Group (of Santonian to Maastrichtian age). Both microfossil and macrofaunal information have been integrated in order to construct a biostratigraphical framework for the basin and develop a tectono-stratigraphical model. Structures exposed onshore, which have occasionally been interpreted as Albian reefs, are thought to be irregularly shaped, limestone olistoliths and olistostromes produced by significant intra-Cretaceous faulting and slumping within the basin.
{"title":"Palaeoenvironment and Bio-events of the Cretaceous Sediments of the Cauvery Basin, India","authors":"R. Venkatachalapathy, L. Harini, M. B. Hart, Watkinson M. P.","doi":"10.1144/sp545-2023-123","DOIUrl":"https://doi.org/10.1144/sp545-2023-123","url":null,"abstract":"\u0000 \u0000 The Cauvery Basin is an important rift margin basin on the east coast of India. It's long research history began in the mid-nineteenth century with the pioneering work of H.F. Blanford. While much of the Cretaceous succession in the basin is fault-controlled, some of the recorded events represent global sea level changes, especially in the mid-Cretaceous. Macrofossils (ammonites, bivalves,\u0000 etc.\u0000 ) and foraminifera are abundant throughout, and there is an important occurrence of fossil wood and ‘log-grounds’ in the Turonian-Coniacian. The basin is sub-divided into a series of sub-basins (known as depressions in the earlier literature) which - in places - have their own distinctive depositional history.\u0000 \u0000 The results of our collective fieldwork have provided a re-assessment of the lithostratigraphy, biostratigraphy and the tectono-stratigraphical history of the Ariyalur outcrop. Three sedimentary units have been identified; the syn-rift Gondwana Group (of early Cretaceous age), the syn-rift Uttatur Group (of Albian to Coniacian age) and the post-rift Ariyalur Group (of Santonian to Maastrichtian age). Both microfossil and macrofaunal information have been integrated in order to construct a biostratigraphical framework for the basin and develop a tectono-stratigraphical model. Structures exposed onshore, which have occasionally been interpreted as Albian reefs, are thought to be irregularly shaped, limestone olistoliths and olistostromes produced by significant intra-Cretaceous faulting and slumping within the basin.","PeriodicalId":281618,"journal":{"name":"Geological Society, London, Special Publications","volume":"4 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141379623","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}
M. Simmons, M. Bidgood, R. Davies, H. Droste, Bruce Levell, P. Razin, F. V. van Buchem
Shallow-marine carbonate deposition was widespread across the Arabian Plate during much of the Late Permian - Mesozoic but was significantly interrupted by a major tectonically-driven stratigraphic reorganisation that took place within the Turonian. Published literature terms this the “Wasia-Aruma Break”, “the mid-Turonian Unconformity”, or “K150 Sequence Boundary (SB)”. It is widely understood that this event relates to subduction in a closing Neotethys Ocean and obduction onto the continental margin, especially in the south-eastern part of the plate. As well as a change in facies, a hiatus of variable duration is present, associated with erosion of the underlying stratigraphy. Despite the event being known for several decades, precision on its timing has been lacking due to the limitations of biostratigraphic data and because few other chronostratigraphic proxies have been employed. In order to rectify this, all relevant biostratigraphic data from across the Arabian Plate has been synthesised and evaluated in the context of a review of chronostratigraphic calibration of standard biozones from multiple fossil groups. This shows that the youngest preserved rocks beneath K150 SB can be assigned to the middle Turonian helvetica planktonic foraminifera zone or woollgari ammonite zone. The oldest rocks above K150 SB can be assigned to the same biozones, supporting the assertions that it is a very short duration event. Whilst obduction may have initiated earlier (as supported by the recognition of precursor events), crustal loading was sufficient by 91.5 Ma to develop a forebulge in the eastern part of the plate with associated uplift and erosion. A review of relative sea-level change during the Turonian has been carried out to investigate eustatic signals during this time. In multiple sections around the world, a sea-level fall in the upper part of the woollgari Zone of European usage can be detected. This appears to coincide with an episode of climate cooling. However, despite there being correspondence between K150 SB and a significant eustatic event, this seems mostly coincidental as the tectonic drivers at this time across Arabia were much more dramatic. This is especially true in south-eastern Arabia. In north-western Arabia, tectonic quiescence may have allowed eustasy to dominate. In any case, a eustatic fall would have amplified the effects of tectonics across the entire region.
{"title":"Intra-Turonian stratigraphic reorganisation on the Arabian Plate","authors":"M. Simmons, M. Bidgood, R. Davies, H. Droste, Bruce Levell, P. Razin, F. V. van Buchem","doi":"10.1144/sp545-2023-207","DOIUrl":"https://doi.org/10.1144/sp545-2023-207","url":null,"abstract":"\u0000 Shallow-marine carbonate deposition was widespread across the Arabian Plate during much of the Late Permian - Mesozoic but was significantly interrupted by a major tectonically-driven stratigraphic reorganisation that took place within the Turonian. Published literature terms this the “Wasia-Aruma Break”, “the mid-Turonian Unconformity”, or “K150 Sequence Boundary (SB)”. It is widely understood that this event relates to subduction in a closing Neotethys Ocean and obduction onto the continental margin, especially in the south-eastern part of the plate. As well as a change in facies, a hiatus of variable duration is present, associated with erosion of the underlying stratigraphy.\u0000 \u0000 Despite the event being known for several decades, precision on its timing has been lacking due to the limitations of biostratigraphic data and because few other chronostratigraphic proxies have been employed. In order to rectify this, all relevant biostratigraphic data from across the Arabian Plate has been synthesised and evaluated in the context of a review of chronostratigraphic calibration of standard biozones from multiple fossil groups. This shows that the youngest preserved rocks beneath K150 SB can be assigned to the middle Turonian\u0000 helvetica\u0000 planktonic foraminifera zone or\u0000 woollgari\u0000 ammonite zone. The oldest rocks above K150 SB can be assigned to the same biozones, supporting the assertions that it is a very short duration event. Whilst obduction may have initiated earlier (as supported by the recognition of precursor events), crustal loading was sufficient by 91.5 Ma to develop a forebulge in the eastern part of the plate with associated uplift and erosion.\u0000 \u0000 \u0000 A review of relative sea-level change during the Turonian has been carried out to investigate eustatic signals during this time. In multiple sections around the world, a sea-level fall in the upper part of the\u0000 woollgari\u0000 Zone of European usage can be detected. This appears to coincide with an episode of climate cooling. However, despite there being correspondence between K150 SB and a significant eustatic event, this seems mostly coincidental as the tectonic drivers at this time across Arabia were much more dramatic. This is especially true in south-eastern Arabia. In north-western Arabia, tectonic quiescence may have allowed eustasy to dominate. In any case, a eustatic fall would have amplified the effects of tectonics across the entire region.\u0000","PeriodicalId":281618,"journal":{"name":"Geological Society, London, Special Publications","volume":"5 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141267536","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}
K. Randive, S. Jawadand, T. Meshram, Manoj Sahu, B. Belyatsky, M. Dora, R. Meshram, J. Vijaya Kumar, S. Dandekar, Tejashree Raut, M. Korakoppa, R. Bhutani
This paper discusses the petrogenesis of lamprophyre dykes occurring in the Chhota Udaipur Alkaline-Carbonatite Sub-province (CUACS). Both calc-alkaline as well as alkaline varieties occur in the area. The major and trace elements geochemistry of the CUACS lamprophyres display good correlation with each other and other Deccan-related lamprophyres. Trace-elements ratios reveal a minor role of crustal contamination and support their derivation from partial melting of a lithospheric mantle source that is significantly modified by interaction with asthenosphere-derived melts emanating from an impinging mantle plume. The restricted initial 87 Sr/ 86 Sr (0.70599-0.70658) and 143 Nd/ 144 Nd (0.512501-0.512513) ratios of the CUACS lamprophyres further attest to their derivation from an OIB-type parental melt. Their negative εNdi values (−1 to −6) are comparable with other lamprophyres of the Deccan LIP. The lamprophyres from the present study share similar geochemical characteristics to Mt. Girnar lamprophyres, which are derived from the spinel-garnet transition zone at a depth of ∼85 km, distinct from the previously considered depth (∼100 km) of the post-Deccan lithosphere-asthenosphere boundary (LAB) beneath the NW India. Such geochemical characteristics of the Chhota Udaipur lamprophyres, indicate a vital role of plume-lithosphere interaction at the thermal boundary layer at about ∼66 Ma. Supplementary material at https://doi.org/10.6084/m9.figshare.c.7244764
{"title":"Lamprophyres from the Chhota Udaipur Alkaline – Carbonatite Sub-Province, Deccan Large Igneous Province, India: Implication for Petrogenesis and Crustal Structure","authors":"K. Randive, S. Jawadand, T. Meshram, Manoj Sahu, B. Belyatsky, M. Dora, R. Meshram, J. Vijaya Kumar, S. Dandekar, Tejashree Raut, M. Korakoppa, R. Bhutani","doi":"10.1144/sp551-2023-112","DOIUrl":"https://doi.org/10.1144/sp551-2023-112","url":null,"abstract":"\u0000 \u0000 This paper discusses the petrogenesis of lamprophyre dykes occurring in the Chhota Udaipur Alkaline-Carbonatite Sub-province (CUACS). Both calc-alkaline as well as alkaline varieties occur in the area. The major and trace elements geochemistry of the CUACS lamprophyres display good correlation with each other and other Deccan-related lamprophyres. Trace-elements ratios reveal a minor role of crustal contamination and support their derivation from partial melting of a lithospheric mantle source that is significantly modified by interaction with asthenosphere-derived melts emanating from an impinging mantle plume. The restricted initial\u0000 87\u0000 Sr/\u0000 86\u0000 Sr (0.70599-0.70658) and\u0000 143\u0000 Nd/\u0000 144\u0000 Nd (0.512501-0.512513) ratios of the CUACS lamprophyres further attest to their derivation from an OIB-type parental melt. Their negative εNdi values (−1 to −6) are comparable with other lamprophyres of the Deccan LIP. The lamprophyres from the present study share similar geochemical characteristics to Mt. Girnar lamprophyres, which are derived from the spinel-garnet transition zone at a depth of ∼85 km, distinct from the previously considered depth (∼100 km) of the post-Deccan lithosphere-asthenosphere boundary (LAB) beneath the NW India. Such geochemical characteristics of the Chhota Udaipur lamprophyres, indicate a vital role of plume-lithosphere interaction at the thermal boundary layer at about ∼66 Ma.\u0000 \u0000 \u0000 Supplementary material at\u0000 https://doi.org/10.6084/m9.figshare.c.7244764\u0000","PeriodicalId":281618,"journal":{"name":"Geological Society, London, Special Publications","volume":"17 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141104676","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 aims to investigate the earliest imprint of Deccan rift magmatism as preserved in alkali basalts from the northwestern Indian shield. The alkali basalts are petrographically classified as nephelinites and basanites. They are silica undersaturated and their high Mg#, CaO/Al 2 O 3 , Cr and Ni indicate their primitive character. Geochemically, they are similar to global ocean island basalts; their bulk rock trace elements and Sr-Nd-Hf isotopic signatures suggest their derivation from garnet-bearing peridotite field. However, their elevated values of Sr/Sm, Sm/Hf, Zr/Hf, Nb/Ta; positive Ba, Sr and negative Zr, Hf spikes suggest that the magma source represents a mixture of garnet peridotites and carbonated melts. Estimated primary melt compositions closely follow the trajectory defined by the high pressure experimental partial melting trend of a low-carbonated peridotite source. The melting environment approximates to a high mantle potential temperature. Low 87Sr/86Sr ratio and a negative correlation between 176Hf/177Hf and 143Nd/144Nd of the alkali basalts suggest that the mantle source is a mixture of a depleted Indian MORB-type mantle and an enriched mantle type 2 (EMII). We correlate this event with the melting of the leading edge of the Réunion plume head during Gondwana break-up in a relatively short span of the Cretaceous/Paleogene boundary. Supplementary material at https://doi.org/10.6084/m9.figshare.c.7243078
这项研究的目的是调查印度西北部地盾的碱性玄武岩中保存的德干断裂岩浆活动的最早印记。这些碱性玄武岩在岩石学上被划分为霞石和玄武岩。它们二氧化硅含量不足，高镁#、CaO/Al 2 O 3、Cr 和 Ni 表明了它们的原始特征。在地球化学方面，它们与全球海洋岛屿玄武岩相似；它们的大块岩石痕量元素和 Sr-Nd-Hf 同位素特征表明它们来自含石榴石的橄榄岩场。然而，它们的 Sr/Sm、Sm/Hf、Zr/Hf、Nb/Ta 值升高；Ba、Sr 呈正值，Zr、Hf 呈负值，这表明岩浆源是石榴石橄榄岩和碳酸盐熔体的混合物。估计的原生熔体成分与低碳橄榄岩源的高压实验部分熔化趋势所确定的轨迹非常接近。熔融环境近似于高地幔势温。低87Sr/86Sr比值以及碱性玄武岩的176Hf/177Hf和143Nd/144Nd之间的负相关表明，地幔源是贫化的印度MORB型地幔和富集的2型地幔（EMII）的混合物。我们将这一事件与冈瓦纳断裂期间留尼汪羽流头部前缘在白垩纪/古近纪边界相对较短的时间内发生的熔融联系起来。 补充材料见 https://doi.org/10.6084/m9.figshare.c.7243078
{"title":"Intraplate alkali basalts related to end-Cretaceous Deccan magmatism: Implications to tectonomagmatic processes","authors":"Soumi Chattopadhaya, Biswajit Ghosh, Chuan Zhou Liu, Debaditya Bandyopadhyay, Sankhadeep Roy, Archisman Dhar, Manojit Koley, Deepak Kumar","doi":"10.1144/sp551-2023-86","DOIUrl":"https://doi.org/10.1144/sp551-2023-86","url":null,"abstract":"\u0000 \u0000 This study aims to investigate the earliest imprint of Deccan rift magmatism as preserved in alkali basalts from the northwestern Indian shield. The alkali basalts are petrographically classified as nephelinites and basanites. They are silica undersaturated and their high Mg#, CaO/Al\u0000 2\u0000 O\u0000 3\u0000 , Cr and Ni indicate their primitive character. Geochemically, they are similar to global ocean island basalts; their bulk rock trace elements and Sr-Nd-Hf isotopic signatures suggest their derivation from garnet-bearing peridotite field. However, their elevated values of Sr/Sm, Sm/Hf, Zr/Hf, Nb/Ta; positive Ba, Sr and negative Zr, Hf spikes suggest that the magma source represents a mixture of garnet peridotites and carbonated melts. Estimated primary melt compositions closely follow the trajectory defined by the high pressure experimental partial melting trend of a low-carbonated peridotite source. The melting environment approximates to a high mantle potential temperature. Low 87Sr/86Sr ratio and a negative correlation between 176Hf/177Hf and 143Nd/144Nd of the alkali basalts suggest that the mantle source is a mixture of a depleted Indian MORB-type mantle and an enriched mantle type 2 (EMII). We correlate this event with the melting of the leading edge of the Réunion plume head during Gondwana break-up in a relatively short span of the Cretaceous/Paleogene boundary.\u0000 \u0000 \u0000 Supplementary material at\u0000 https://doi.org/10.6084/m9.figshare.c.7243078\u0000","PeriodicalId":281618,"journal":{"name":"Geological Society, London, Special Publications","volume":"30 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141104023","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}
Robert A. Spicer, Alex Farnsworth, Tao Su, Lin Ding, C. Witkowski, Shufeng Li, Zhongyu Xiong, Zhekun Zhou, Shihu Li, Alice C. Hughes, Paul J. Valdes, Mike Widdowson, Xinwen Zhang, Songlin He, Jia Liu, Jian Huang, A. Herman, Qiang Xu, Xiaoyan Liu, Jianhua Jin, R. Pancost, D. J. Lunt, Shitao Zhang
Within the ongoing controversy regarding the orogeny of the Tibetan Plateau region, two directly-conflicting endmember frameworks have emerged, where either: 1) a high central ‘proto-plateau’ existed prior to the onset of India-Asia continental collision, or 2) the early Paleogene central Tibet comprised a wide E-W oriented lowland ∼1-2 km above sea level, bounded by high (> 4.5 km) mountain systems. Reconstructing plateau development correctly is fundamental to running realistic Earth system models that explore monsoon and biodiversity evolution in the region. Understanding the interplay between monsoon dynamics, landscape and biodiversity are critical for future resource management. We explore the strengths and weaknesses of different palaeoaltimetric methodologies as applied across the Tibetan region. Combining methodologies, appreciating the vulnerabilities arising from their underlying assumptions and testing them using numerical climate models, produces consilience (agreement) allowing further refinement of both models and proxies. We argue that an east-west oriented Paleogene Central Tibetan Valley was a cradle and conduit for thermophilic biota seeding the modern regional biodiversity. The rise of eastern Tibet intensified regional rainfall and erosion, which increased topographic relief and biodiversification. Gradual monsoon development reflected the evolving topography, but modern-like Asian monsoons developed only after a plateau formed in the Miocene.
{"title":"The Progressive Co-evolutionary Development of the Pan-Tibetan Highlands, the Asian Monsoon system and Asian Biodiversity","authors":"Robert A. Spicer, Alex Farnsworth, Tao Su, Lin Ding, C. Witkowski, Shufeng Li, Zhongyu Xiong, Zhekun Zhou, Shihu Li, Alice C. Hughes, Paul J. Valdes, Mike Widdowson, Xinwen Zhang, Songlin He, Jia Liu, Jian Huang, A. Herman, Qiang Xu, Xiaoyan Liu, Jianhua Jin, R. Pancost, D. J. Lunt, Shitao Zhang","doi":"10.1144/sp549-2023-180","DOIUrl":"https://doi.org/10.1144/sp549-2023-180","url":null,"abstract":"\u0000 Within the ongoing controversy regarding the orogeny of the Tibetan Plateau region, two directly-conflicting endmember frameworks have emerged, where either: 1) a high central ‘proto-plateau’ existed prior to the onset of India-Asia continental collision, or 2) the early Paleogene central Tibet comprised a wide E-W oriented lowland ∼1-2 km above sea level, bounded by high (> 4.5 km) mountain systems. Reconstructing plateau development correctly is fundamental to running realistic Earth system models that explore monsoon and biodiversity evolution in the region. Understanding the interplay between monsoon dynamics, landscape and biodiversity are critical for future resource management. We explore the strengths and weaknesses of different palaeoaltimetric methodologies as applied across the Tibetan region. Combining methodologies, appreciating the vulnerabilities arising from their underlying assumptions and testing them using numerical climate models, produces consilience (agreement) allowing further refinement of both models and proxies. We argue that an east-west oriented Paleogene Central Tibetan Valley was a cradle and conduit for thermophilic biota seeding the modern regional biodiversity. The rise of eastern Tibet intensified regional rainfall and erosion, which increased topographic relief and biodiversification. Gradual monsoon development reflected the evolving topography, but modern-like Asian monsoons developed only after a plateau formed in the Miocene.","PeriodicalId":281618,"journal":{"name":"Geological Society, London, Special Publications","volume":"16 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141107975","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}
R. Pandey, A. Pandey, L. Krmíček, C. Cucciniello, D. Müller
The term ‘alkaline rocks’ comprises alkali basalts, tephrites, phonolites, trachytes and their plutonic equivalents, including carbonatites and lamprophyres. Their study can aid the interpretation of ancient terranes and their geodynamic setting. Alkaline rocks may also host precious- and rare-metal mineralization, the latter representing critical commodities for modern green-energy technologies.
{"title":"About this title - Alkaline Rocks: Economic and Geodynamic Significance through Geological Time","authors":"R. Pandey, A. Pandey, L. Krmíček, C. Cucciniello, D. Müller","doi":"10.1144/sp551-000","DOIUrl":"https://doi.org/10.1144/sp551-000","url":null,"abstract":"The term ‘alkaline rocks’ comprises alkali basalts, tephrites, phonolites, trachytes and their plutonic equivalents, including carbonatites and lamprophyres. Their study can aid the interpretation of ancient terranes and their geodynamic setting. Alkaline rocks may also host precious- and rare-metal mineralization, the latter representing critical commodities for modern green-energy technologies.","PeriodicalId":281618,"journal":{"name":"Geological Society, London, Special Publications","volume":"34 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141109615","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 Tanzania Drilling Program (TDP) recovered hemipelagic sediments from land-based boreholes that yielded extraordinarily well-preserved, diverse Turonian foraminifera. Reliable oxygen and carbon isotopic analyses through most of the Turonian Stage and biostratigraphic data were documented. This study compares Turonian foraminiferal population dynamics and associated geochemical proxy records among the TDP boreholes with correlative records from Ocean Drilling Program Site 762 (Exmouth Plateau, eastern Indian Ocean). The two regions were separated by ∼12° latitude and ∼5,000 km of ocean with the Indian continental plate located between. Taxonomic turnover is similar is nearly simultaneous in both regions across the transition from the Helvetoglobotruncana helvetica Zone to the Falsotruncana maslakovae Zone (∼93.0 Ma). Changes include overlapping extinctions of all helvetoglobotruncanids, most dicarinellids and one species of Praeglobotruncana and subsequent first appearances of marginotruncanid and falsotruncanid species. Increased abundance of biserial planktonic foraminifera is recorded at multiple TDP sites and at Site 762 across the contact of the Fa. maslakovae and Huberella huberi Zone about 0.5 m.y. after the Hv. helvetica / Fa. maslakovae transition. Geochemical records at the two sites do not indicate associated paleoenvironmental changes in surface water conditions that would explain coordinated changes in species composition on opposites sides of the Indian Ocean.
{"title":"Population dynamics and paleoenvironmental inferences of Turonian planktonic foraminiferal assemblages from SE Tanzania and ODP Site 762 (Exmouth Plateau, eastern Indian Ocean)","authors":"B. Huber, M. Petrizzo, K. MacLeod","doi":"10.1144/sp545-2023-171","DOIUrl":"https://doi.org/10.1144/sp545-2023-171","url":null,"abstract":"\u0000 \u0000 The Tanzania Drilling Program (TDP) recovered hemipelagic sediments from land-based boreholes that yielded extraordinarily well-preserved, diverse Turonian foraminifera. Reliable oxygen and carbon isotopic analyses through most of the Turonian Stage and biostratigraphic data were documented. This study compares Turonian foraminiferal population dynamics and associated geochemical proxy records among the TDP boreholes with correlative records from Ocean Drilling Program Site 762 (Exmouth Plateau, eastern Indian Ocean). The two regions were separated by ∼12° latitude and ∼5,000 km of ocean with the Indian continental plate located between. Taxonomic turnover is similar is nearly simultaneous in both regions across the transition from the\u0000 Helvetoglobotruncana helvetica\u0000 Zone to the\u0000 Falsotruncana maslakovae\u0000 Zone (∼93.0 Ma). Changes include overlapping extinctions of all helvetoglobotruncanids, most dicarinellids and one species of\u0000 Praeglobotruncana\u0000 and subsequent first appearances of marginotruncanid and falsotruncanid species. Increased abundance of biserial planktonic foraminifera is recorded at multiple TDP sites and at Site 762 across the contact of the\u0000 Fa. maslakovae\u0000 and\u0000 Huberella huberi\u0000 Zone about 0.5 m.y. after the\u0000 Hv. helvetica\u0000 /\u0000 Fa. maslakovae\u0000 transition. Geochemical records at the two sites do not indicate associated paleoenvironmental changes in surface water conditions that would explain coordinated changes in species composition on opposites sides of the Indian Ocean.\u0000","PeriodicalId":281618,"journal":{"name":"Geological Society, London, Special Publications","volume":"14 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140981978","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}
Thorsten Hörbrand, K. Beichel, D. Bendias, A. Savvatis, Thomas Kohl
The Upper Jurassic ‘Malm’ carbonates of southern Germany are currently the most developed reservoir for geothermal energy production in Germany. Although many studies investigated the Malm carbonate reservoir, few studies focused on the paleokarst system - despite the fact, that the reservoir is frequently referred to as “Malmkarst”. Data from 25 wells in the Malm reservoir, including well logs, seismic data, and hydraulic information, systematically demonstrate the presence of karstification. This is apparent in the form of large sinkholes and amplitude anomalies on the seismic scale, as well as caves observed in the image log and caliper log data. Flowmeter logs correlated with the karstified section on the image log reveal thin zones of elevated permeability, contributing most of the flow at the wellbore scale. The comparison between measurements from core data and well tests provide evidence of the reservoir's excess permeability, exhibiting values several orders of magnitude higher than those measurable in cores. The stratigraphic record suggests that karstification occurred during the Jurassic and Cretaceous, prior to the burial of the carbonates by the sediments of the alpine molasse basin.
{"title":"Karst control on reservoir performance of a developed carbonate geothermal reservoir in Munich, Germany","authors":"Thorsten Hörbrand, K. Beichel, D. Bendias, A. Savvatis, Thomas Kohl","doi":"10.1144/sp548-2024-42","DOIUrl":"https://doi.org/10.1144/sp548-2024-42","url":null,"abstract":"\u0000 The Upper Jurassic ‘Malm’ carbonates of southern Germany are currently the most developed reservoir for geothermal energy production in Germany. Although many studies investigated the Malm carbonate reservoir, few studies focused on the paleokarst system - despite the fact, that the reservoir is frequently referred to as “Malmkarst”. Data from 25 wells in the Malm reservoir, including well logs, seismic data, and hydraulic information, systematically demonstrate the presence of karstification. This is apparent in the form of large sinkholes and amplitude anomalies on the seismic scale, as well as caves observed in the image log and caliper log data. Flowmeter logs correlated with the karstified section on the image log reveal thin zones of elevated permeability, contributing most of the flow at the wellbore scale. The comparison between measurements from core data and well tests provide evidence of the reservoir's excess permeability, exhibiting values several orders of magnitude higher than those measurable in cores. The stratigraphic record suggests that karstification occurred during the Jurassic and Cretaceous, prior to the burial of the carbonates by the sediments of the alpine molasse basin.","PeriodicalId":281618,"journal":{"name":"Geological Society, London, Special Publications","volume":"22 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140984232","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 study of meandering patterns created by geophysical flows is important for a number of fundamental and applied research topics, including stream and wetland restoration, land management, infrastructure design, oil exploration and production, carbon sequestration, flood-hazard mitigation, and planetary paleoenvironmental reconstructions. This volume, Meandering Streamflows: Patterns and Processes across Landscapes and Scales , contains 13 papers that present field, laboratory, and numerical investigations of meandering channels found in distinct environmental and geological contexts, and focus on how the interactions of different autogenic and allogenic processes, both in the horizontal and the vertical dimension, affect meander kinematics and the resulting morphology, sedimentology, and stratigraphic architecture. In this introductory chapter, we offer an overview of the evolution of scientific research on meandering streams over time, aiming to review and discuss meandering patterns in both fluvial and non-fluvial settings. Additionally, we present a new compilation of data on meander morphological features, drawn from both existing literature and novel sources, encompassing over 8000 meander bends discovered across a diverse array of environments.
{"title":"Meandering Streamflows across Landscapes and Scales: a Review and Discussion","authors":"A. Finotello, Paul R. Durkin, Zoltan Sylvester","doi":"10.1144/sp540-2024-33","DOIUrl":"https://doi.org/10.1144/sp540-2024-33","url":null,"abstract":"\u0000 \u0000 The study of meandering patterns created by geophysical flows is important for a number of fundamental and applied research topics, including stream and wetland restoration, land management, infrastructure design, oil exploration and production, carbon sequestration, flood-hazard mitigation, and planetary paleoenvironmental reconstructions. This volume,\u0000 Meandering Streamflows: Patterns and Processes across Landscapes and Scales\u0000 , contains 13 papers that present field, laboratory, and numerical investigations of meandering channels found in distinct environmental and geological contexts, and focus on how the interactions of different autogenic and allogenic processes, both in the horizontal and the vertical dimension, affect meander kinematics and the resulting morphology, sedimentology, and stratigraphic architecture. In this introductory chapter, we offer an overview of the evolution of scientific research on meandering streams over time, aiming to review and discuss meandering patterns in both fluvial and non-fluvial settings. Additionally, we present a new compilation of data on meander morphological features, drawn from both existing literature and novel sources, encompassing over 8000 meander bends discovered across a diverse array of environments.\u0000","PeriodicalId":281618,"journal":{"name":"Geological Society, London, Special Publications","volume":" 86","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140993369","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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