Pub Date : 2025-07-01DOI: 10.1016/j.jop.2025.02.003
Xue-Yan Li , Gi-Soo Nam , Shu-Feng Li , Anna Averyanova , Yi Yang , Ma-Byong Yoon , Lin-Bo Jia
Naturally occurring in the subtropical regions of China to Korea, Chinese Holly (Ilex cornuta Lindl. & Paxton, Aquifoliaceae), is widely cultivated as an ornamental plant. However, the origins of the phenotypical diversity of the species as well as its geographical history remain elusive. Here we report 50 exceptionally well-preserved fossil leaves of the I. cornuta lineage from the middle Miocene of South Korea. These fossils showcase delicate details, encompassing both adaxial and abaxial surfaces, as well as primary to quinternary venation patterns. The varied leaf morphologies, ranging from three to seven spines, demonstrate that these leaf morphologies of I. cornuta were established by the middle Miocene. Furthermore, fossil discoveries from the middle and late Miocene of Korea and China, coupled with the enduring presence of highly suitable habitats in Asia since the late Paleogene, suggest a longstanding persistence of the I. cornuta lineage in this region. The identification of closely related fossils from the Miocene to Pliocene of Europe implies potential floristic interchange between the continents, facilitated by the regression of the Turgai Strait in the Paleogene. This is consistent with the broad suitable habitat of the lineage, which once spanned Europe and Asia from the late Eocene to early Oligocene. Our study provides an example for integrating fossil records with ecological niche modelling to elucidate the biogeographical history of plants.
{"title":"Fossil evidence and ecological niche modelling reveal trait evolution and biogeography of the Ilex cornuta lineage","authors":"Xue-Yan Li , Gi-Soo Nam , Shu-Feng Li , Anna Averyanova , Yi Yang , Ma-Byong Yoon , Lin-Bo Jia","doi":"10.1016/j.jop.2025.02.003","DOIUrl":"10.1016/j.jop.2025.02.003","url":null,"abstract":"<div><div>Naturally occurring in the subtropical regions of China to Korea, Chinese Holly (<em>Ilex cornuta</em> Lindl. & Paxton, Aquifoliaceae), is widely cultivated as an ornamental plant. However, the origins of the phenotypical diversity of the species as well as its geographical history remain elusive. Here we report 50 exceptionally well-preserved fossil leaves of the <em>I</em>. <em>cornuta</em> lineage from the middle Miocene of South Korea. These fossils showcase delicate details, encompassing both adaxial and abaxial surfaces, as well as primary to quinternary venation patterns. The varied leaf morphologies, ranging from three to seven spines, demonstrate that these leaf morphologies of <em>I. cornuta</em> were established by the middle Miocene. Furthermore, fossil discoveries from the middle and late Miocene of Korea and China, coupled with the enduring presence of highly suitable habitats in Asia since the late Paleogene, suggest a longstanding persistence of the <em>I. cornuta</em> lineage in this region. The identification of closely related fossils from the Miocene to Pliocene of Europe implies potential floristic interchange between the continents, facilitated by the regression of the Turgai Strait in the Paleogene. This is consistent with the broad suitable habitat of the lineage, which once spanned Europe and Asia from the late Eocene to early Oligocene. Our study provides an example for integrating fossil records with ecological niche modelling to elucidate the biogeographical history of plants.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100251"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721244","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 : 2025-07-01DOI: 10.1016/j.jop.2025.100260
Ivana Jovanić , Aleksandra Šajnović , Bojan Glavaš-Trbić , Sanja Stojadinović , Nikola Burazer , Branimir Jovančićević
Inorganic and organic geochemical analyses, assisted by micropaleontological investigations, were performed on the Paskovac sediments to differentiate the Cretaceous and Paleogene deposits in Internal Dinarides region. Owning to the presence of fossil assemblages in the in Upper Cretaceous sediments and their scarcity in the Paleogene siliciclastic sediments, the entire Paskovac area was fundamentally incorrectly classified as the Campanian–Maastrichtian. Besides, the Paskovac sedimentary sequence was formed as a consequence of the uppermost Cretaceous–Paleogene tectonic shortening of the Dinarides, during which the Maastrichtian sediments were re-deposited within the Paleogene sequence from the underlying Maastrichtian sediments. Therefore, this study employed thin-section microscopy, atomic absorption spectrometry (AAS), and gas chromatography–mass spectrometry (GC–MS) techniques to closely inspect 27 samples from the Paskovac drillhole. The results revealed a clear division of the samples into two groups based on their geochemical similarities. One group marked as Paleogene clastic sediments characterizes the highest content of terrigenous elements, namely SiO2 (49.49 %–62.22 %), Al2O3 (16.18 %–21.75 %), Fe2O3 (3.41 %–6.67 %), TiO2 (0.63 %–0.80 %), along with sulfur content (2.33 %–2.80 %). The organic matter is rich in odd long-chain n-alkanes, C29 regular sterane (>60 %), benzohopanes, retene, cadalene, and benzo[b]naphthofurans, suggesting predominately terrestrial biomass deposited under suboxic–oxic conditions. Another group, represented by carbonates (CaO up to 51.02 %), contains Maastrichtian assemblages (e.g., Siderolites calcitrapoides), indicating shallow-marine depositional settings. Short-chain even n-alkanes, branched alkanes (e.g., 5,5-diethylalkanes), and C27 regular sterane suggest the presence of biodegraded mixed algal/microbial biomass.
{"title":"Hydrocarbon signatures as a tool for unraveling the stratigraphic problem for Upper Cretaceous–Paleogene sediments from Internal Dinarides, Serbia","authors":"Ivana Jovanić , Aleksandra Šajnović , Bojan Glavaš-Trbić , Sanja Stojadinović , Nikola Burazer , Branimir Jovančićević","doi":"10.1016/j.jop.2025.100260","DOIUrl":"10.1016/j.jop.2025.100260","url":null,"abstract":"<div><div>Inorganic and organic geochemical analyses, assisted by micropaleontological investigations, were performed on the Paskovac sediments to differentiate the Cretaceous and Paleogene deposits in Internal Dinarides region. Owning to the presence of fossil assemblages in the in Upper Cretaceous sediments and their scarcity in the Paleogene siliciclastic sediments, the entire Paskovac area was fundamentally incorrectly classified as the Campanian–Maastrichtian. Besides, the Paskovac sedimentary sequence was formed as a consequence of the uppermost Cretaceous–Paleogene tectonic shortening of the Dinarides, during which the Maastrichtian sediments were re-deposited within the Paleogene sequence from the underlying Maastrichtian sediments. Therefore, this study employed thin-section microscopy, atomic absorption spectrometry (AAS), and gas chromatography–mass spectrometry (GC–MS) techniques to closely inspect 27 samples from the Paskovac drillhole. The results revealed a clear division of the samples into two groups based on their geochemical similarities. One group marked as Paleogene clastic sediments characterizes the highest content of terrigenous elements, namely SiO<sub>2</sub> (49.49 %–62.22 %), Al<sub>2</sub>O<sub>3</sub> (16.18 %–21.75 %), Fe<sub>2</sub>O<sub>3</sub> (3.41 %–6.67 %), TiO<sub>2</sub> (0.63 %–0.80 %), along with sulfur content (2.33 %–2.80 %). The organic matter is rich in odd long-chain <em>n</em>-alkanes, C<sub>29</sub> regular sterane (>60 %), benzohopanes, retene, cadalene, and benzo[<em>b</em>]naphthofurans, suggesting predominately terrestrial biomass deposited under suboxic–oxic conditions. Another group, represented by carbonates (CaO up to 51.02 %), contains Maastrichtian assemblages (e.g., <em>Siderolites calcitrapoides</em>), indicating shallow-marine depositional settings. Short-chain even <em>n</em>-alkanes, branched alkanes (e.g., 5,5-diethylalkanes), and C<sub>27</sub> regular sterane suggest the presence of biodegraded mixed algal/microbial biomass.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100260"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721252","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 : 2025-07-01DOI: 10.1016/j.jop.2025.100262
Nadir Fawad , Dai-Du Fan , Tai-Xun Liu , Muhammad Kamran , Qazi Adnan Ahmed
Since the early Pleistocene, climatic variability has profoundly influenced population dynamics, including the migration of hominins into and out of Africa. In South Asia, Quaternary sediments, particularly those found in the Siwaliks, provide a valuable record of climatic changes relevant to hominin habitation. While the upper Soan Valley in Pakistan has been extensively studied for evidence of hominin to modern human activities, the associated environmental and climatic changes remain underexplored. This study aims to elucidate the climatic evolution of the Quaternary sediments in the Riwat area, with the primary objective of reconstructing the environmental conditions that facilitated long-term hominin settlement and survival. To address this knowledge gap, we analyzed the geochemistry and clay mineralogy of 46 sediment samples utilizing spectroscopy and X-ray diffractometry (XRD), focusing on the Plio-Quaternary period. Our findings reveal three distinct climatic stages. The first stage (Stage I), was characterized by cold conditions during the Pliocene, and was further divided into semi-arid to semi-humid substages based on C-values. This was followed by a cold to humid climatic stage (Stage II) during the early to middle Pleistocene, marked by moderate to high chemical weathering, which was also categorized into semi-arid to semi-humid substages. Within Stage II, a warm and humid phase was inferred during the early to middle Pleistocene, culminating in the coldest and most arid conditions of Stage III during the late Pleistocene to Holocene. The climatic changes observed are indicative of the uplift of the Himalayan-Tibetan Plateau and the influence of the southwestern monsoon on the Indian subcontinent. Moderate to intense monsoonal activity characterized the early to middle Pleistocene, creating conditions conducive to early hominin settlement and adaptation due to the availability of resources. Conversely, environmental conditions during periods of weakened monsoons exhibited an arid climate from the late Pleistocene to Holocene (corresponding to MIS 1-4 in oceanic records). This study enhances our understanding of hominin-climate interactions and has implications for the role of climate in shaping diverse hominin habitation patterns, both globally (out of Africa) and regionally (South Asian) contexts.
{"title":"Unravelling the Pleistocene climatic evolution in the Siwaliks: implications for hominin settlement in the upper Soan Valley, Pakistan","authors":"Nadir Fawad , Dai-Du Fan , Tai-Xun Liu , Muhammad Kamran , Qazi Adnan Ahmed","doi":"10.1016/j.jop.2025.100262","DOIUrl":"10.1016/j.jop.2025.100262","url":null,"abstract":"<div><div>Since the early Pleistocene, climatic variability has profoundly influenced population dynamics, including the migration of hominins into and out of Africa. In South Asia, Quaternary sediments, particularly those found in the Siwaliks, provide a valuable record of climatic changes relevant to hominin habitation. While the upper Soan Valley in Pakistan has been extensively studied for evidence of hominin to modern human activities, the associated environmental and climatic changes remain underexplored. This study aims to elucidate the climatic evolution of the Quaternary sediments in the Riwat area, with the primary objective of reconstructing the environmental conditions that facilitated long-term hominin settlement and survival. To address this knowledge gap, we analyzed the geochemistry and clay mineralogy of 46 sediment samples utilizing spectroscopy and X-ray diffractometry (XRD), focusing on the Plio-Quaternary period. Our findings reveal three distinct climatic stages. The first stage (Stage I), was characterized by cold conditions during the Pliocene, and was further divided into semi-arid to semi-humid substages based on C-values. This was followed by a cold to humid climatic stage (Stage II) during the early to middle Pleistocene, marked by moderate to high chemical weathering, which was also categorized into semi-arid to semi-humid substages. Within Stage II, a warm and humid phase was inferred during the early to middle Pleistocene, culminating in the coldest and most arid conditions of Stage III during the late Pleistocene to Holocene. The climatic changes observed are indicative of the uplift of the Himalayan-Tibetan Plateau and the influence of the southwestern monsoon on the Indian subcontinent. Moderate to intense monsoonal activity characterized the early to middle Pleistocene, creating conditions conducive to early hominin settlement and adaptation due to the availability of resources. Conversely, environmental conditions during periods of weakened monsoons exhibited an arid climate from the late Pleistocene to Holocene (corresponding to MIS 1-4 in oceanic records). This study enhances our understanding of hominin-climate interactions and has implications for the role of climate in shaping diverse hominin habitation patterns, both globally (out of Africa) and regionally (South Asian) contexts.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100262"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522104","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 : 2025-07-01DOI: 10.1016/j.jop.2025.03.004
Hong-Hui Li , Da-Li Yue , Wei Li , Ling-Ling Dan , Yuan Liu , Wu-Rong Wang , Ke-Yu Ren , Ling Tan
In offshore fields with limited well data, intricate geological configurations, and high reservoir heterogeneity, the accurate prediction of sand body distribution and characterization of sedimentary architecture pose significant challenges due to inherent geological uncertainties and data limitations. This study employs a comprehensive approach integrating three key methods to enhance prediction accuracy: (i) fusion of spectral-decomposed seismic attributes, (ii) seismic attribute fusion of target and neighboring zones, and (iii) colored seismic inversion. The first method leverages seismic information across various frequencies, yielding reliable results for sand bodies of different thicknesses. The second method mitigates the impact of seismic responses from adjacent zones on sand body predictions, making it particularly suitable for target intervals where neighboring zones significantly influence the seismic response. The third one, colored seismic inversion enhances the prediction of vertical distribution and the stacking relationships of sand bodies. These methods have been applied in an oilfield in the Pearl River Mouth Basin, southern China. Consequently, the sedimentary architecture of a braided river delta reservoir is successfully characterized, leading to the identification of four distributary channels within a depositional Zone 1 of the Zhujiang Formation. Additionally, a comprehensive workflow integrating well logs, seismic data, and depositional models significantly improves predictions of sand body distribution and sedimentary architecture in complex geological settings, providing critical geological insights for optimizing subsequent oilfield development strategies.
{"title":"Sedimentary architecture characterization by combining well logs and seismic data in river-dominated delta reservoirs: the Pearl River Mouth Basin, South China Sea","authors":"Hong-Hui Li , Da-Li Yue , Wei Li , Ling-Ling Dan , Yuan Liu , Wu-Rong Wang , Ke-Yu Ren , Ling Tan","doi":"10.1016/j.jop.2025.03.004","DOIUrl":"10.1016/j.jop.2025.03.004","url":null,"abstract":"<div><div>In offshore fields with limited well data, intricate geological configurations, and high reservoir heterogeneity, the accurate prediction of sand body distribution and characterization of sedimentary architecture pose significant challenges due to inherent geological uncertainties and data limitations. This study employs a comprehensive approach integrating three key methods to enhance prediction accuracy: (i) fusion of spectral-decomposed seismic attributes, (ii) seismic attribute fusion of target and neighboring zones, and (iii) colored seismic inversion. The first method leverages seismic information across various frequencies, yielding reliable results for sand bodies of different thicknesses. The second method mitigates the impact of seismic responses from adjacent zones on sand body predictions, making it particularly suitable for target intervals where neighboring zones significantly influence the seismic response. The third one, colored seismic inversion enhances the prediction of vertical distribution and the stacking relationships of sand bodies. These methods have been applied in an oilfield in the Pearl River Mouth Basin, southern China. Consequently, the sedimentary architecture of a braided river delta reservoir is successfully characterized, leading to the identification of four distributary channels within a depositional Zone 1 of the Zhujiang Formation. Additionally, a comprehensive workflow integrating well logs, seismic data, and depositional models significantly improves predictions of sand body distribution and sedimentary architecture in complex geological settings, providing critical geological insights for optimizing subsequent oilfield development strategies.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100249"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720962","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 : 2025-07-01DOI: 10.1016/j.jop.2025.100256
Da Li, Jian Fu, Yong-An Qi, Xi-Tong He, Man Li, Fu-Qiang Guo
The transition period from the Cambrian Series 2 to Miaolingian was a pivotal juncture in Earth's history, marking the onset of significant shifts in biodiversity and biomass dynamics during the Phanerozoic. Concurrently, profound transformations occurred in the alteration of sedimentary deposits by trace makers, reshaping benthic ecological spaces. This study employs ichnological and ecological methodologies to construct a comprehensive three-dimensional spatial model for ecospace occupation and ecosystem engineering within the Mantou Formation in the western Henan Province, focusing on the transition between the Cambrian Series 2 and Miaolingian. A meticulous statistical analysis of 22 ichnogenera and 32 ichnospecies in the Mantou Formation revealed nuanced variations, such as a decrease in the proportion of predatory organisms in the lower part of Member 2 of the Mantou Formation and a corresponding increase in the upper part. Simultaneously, non-selective deposit-feeding animals exhibit an ascending trend in the lower part of Member 2 and a descending trend in the upper part of Member 2.
In terms of sediment bioturbation, the lower part of Member 2 is characterized by the exclusive presence of biodiffusors and conveyors, whereas regenerators make their appearance in the upper part of Member 2. Affected by the Redlichiid–Olenellid Extinction Carbon isotope Excursion (ROECE) event, metazoans experienced a shift in control dynamics, with microbial mats becoming dominant. Biological activities became intricately intertwined with microbial mats. In the upper part of Member 2, metazoans started recovering, concomitant with the emergence of Thalassinoides and Treptichnus substantially boasting ecosystem engineering impact (EEI) values. These trace makers rapidly amplified the depth and extent of sediment disturbance, giving rise to a profusion of novel ecological niches and catalyzing the transformation of builder functional groups.
{"title":"The significance of benthic ecospace expansion following the ROECE at the Cambrian Series 2–Miaolingian boundary, western Henan Province, central China","authors":"Da Li, Jian Fu, Yong-An Qi, Xi-Tong He, Man Li, Fu-Qiang Guo","doi":"10.1016/j.jop.2025.100256","DOIUrl":"10.1016/j.jop.2025.100256","url":null,"abstract":"<div><div>The transition period from the Cambrian Series 2 to Miaolingian was a pivotal juncture in Earth's history, marking the onset of significant shifts in biodiversity and biomass dynamics during the Phanerozoic. Concurrently, profound transformations occurred in the alteration of sedimentary deposits by trace makers, reshaping benthic ecological spaces. This study employs ichnological and ecological methodologies to construct a comprehensive three-dimensional spatial model for ecospace occupation and ecosystem engineering within the Mantou Formation in the western Henan Province, focusing on the transition between the Cambrian Series 2 and Miaolingian. A meticulous statistical analysis of 22 ichnogenera and 32 ichnospecies in the Mantou Formation revealed nuanced variations, such as a decrease in the proportion of predatory organisms in the lower part of Member 2 of the Mantou Formation and a corresponding increase in the upper part. Simultaneously, non-selective deposit-feeding animals exhibit an ascending trend in the lower part of Member 2 and a descending trend in the upper part of Member 2.</div><div>In terms of sediment bioturbation, the lower part of Member 2 is characterized by the exclusive presence of biodiffusors and conveyors, whereas regenerators make their appearance in the upper part of Member 2. Affected by the Redlichiid–Olenellid Extinction Carbon isotope Excursion (ROECE) event, metazoans experienced a shift in control dynamics, with microbial mats becoming dominant. Biological activities became intricately intertwined with microbial mats. In the upper part of Member 2, metazoans started recovering, concomitant with the emergence of <em>Thalassinoides</em> and <em>Treptichnus</em> substantially boasting ecosystem engineering impact (EEI) values. These trace makers rapidly amplified the depth and extent of sediment disturbance, giving rise to a profusion of novel ecological niches and catalyzing the transformation of builder functional groups.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100256"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721248","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 paper investigates the sedimentology and geochemistry of the black shale deposit of the Rampur Shale Member and interprets the depositional environment, the provenance of the sediments, and the paleoclimatic and paleo-redox conditions to elucidate the evolution history of the Vindhyan Basin in central India during the Mesoproterozoic time. The Rampur Shale Member consists of five facies, representing a fining-upward succession dominated by a coarse-grained sandstone-siltstone alternation at the basal part with an increasing shale content towards the top, culminating into a black shale deposit. Process-based facies analysis documents the shift in the depositional environment from the lower shoreface to the outer part of the continental shelf, suggesting a basin-wide marine transgression which resulted in the deposition of the black shale within the maximum flooding zone (MFZ). Abundant organic matter, with δ13Corg values ranging between −25‰ and −34.30‰, preserved in the form of the crinkly laminated, lensoidal, and spheroidal-shaped microbial mat growth on the sediment surface contributes to the characteristic dark hue of the black shale, which is further supplemented by the high TOC (Total Organic Carbon) content of the black shale. Several geochemical proxies suggest that the sediments were sourced predominantly from felsic igneous provinces; however, increased contributions from mafic sources were recorded during the later stages of deposition. The weathering intensity was high, and the black shale was deposited under humid climatic conditions. The paleoredox proxies suggest predominantly anoxic depositional conditions, most likely forming via organic matter degradation. The paleosalinity remained low due to the epicontinental nature of the basin, possibly as a consequence of dilution by freshwater influx from the basin margin. The trace metal proxies suggest the prevalence of upwelling conditions, perhaps resulting in the increased bio-productivity during the black shale deposition. Numerous slide planes at successive intervals bear the signature of basin subsidence and deepening, facilitating basin-wide black shale formation.
{"title":"Sedimentology, sequence stratigraphy and geochemical reappraisal of the Mesoproterozoic Rampur Shale, Vindhyan Basin, India: Implications for paleoenvironment and basin evolution","authors":"Indrani Mondal , Adrita Choudhuri , Tathagata Roy Choudhury , Shilpa Srimani , Amlan Koner , Sunipa Mandal , Subir Sarkar","doi":"10.1016/j.jop.2025.100259","DOIUrl":"10.1016/j.jop.2025.100259","url":null,"abstract":"<div><div>This paper investigates the sedimentology and geochemistry of the black shale deposit of the Rampur Shale Member and interprets the depositional environment, the provenance of the sediments, and the paleoclimatic and paleo-redox conditions to elucidate the evolution history of the Vindhyan Basin in central India during the Mesoproterozoic time. The Rampur Shale Member consists of five facies, representing a fining-upward succession dominated by a coarse-grained sandstone-siltstone alternation at the basal part with an increasing shale content towards the top, culminating into a black shale deposit. Process-based facies analysis documents the shift in the depositional environment from the lower shoreface to the outer part of the continental shelf, suggesting a basin-wide marine transgression which resulted in the deposition of the black shale within the maximum flooding zone (MFZ). Abundant organic matter, with δ<sup>13</sup>C<sub>org</sub> values ranging between −25‰ and −34.30‰, preserved in the form of the crinkly laminated, lensoidal, and spheroidal-shaped microbial mat growth on the sediment surface contributes to the characteristic dark hue of the black shale, which is further supplemented by the high TOC (Total Organic Carbon) content of the black shale. Several geochemical proxies suggest that the sediments were sourced predominantly from felsic igneous provinces; however, increased contributions from mafic sources were recorded during the later stages of deposition. The weathering intensity was high, and the black shale was deposited under humid climatic conditions. The paleoredox proxies suggest predominantly anoxic depositional conditions, most likely forming via organic matter degradation. The paleosalinity remained low due to the epicontinental nature of the basin, possibly as a consequence of dilution by freshwater influx from the basin margin. The trace metal proxies suggest the prevalence of upwelling conditions, perhaps resulting in the increased bio-productivity during the black shale deposition. Numerous slide planes at successive intervals bear the signature of basin subsidence and deepening, facilitating basin-wide black shale formation.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100259"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721251","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 : 2025-07-01DOI: 10.1016/j.jop.2025.100264
Lei-Gang Zhang, Hong-Jun Qu, Peng Li
The Devonian Liuling Group (DLLG) and its surrounding strata provide massive information about the Paleozoic subduction–suture–extension process of the North China Block (NCB) and South China Block (SCB). Systematic field-based sedimentology, sandstone modal composition, whole-rock elemental composition, and detrital zircon U–Pb dating were employed. The sedimentary sequence of DLLG shows that the water depth deepened and then shallowed, which is characteristic of an extensional basin. Analysis of the tectonic setting and geochronology revealed that the fore-arc sedimentary system (FAS) and DLLG were sourced from the North Qinling Belt (NQB) and NCB. An age population with a single peak at 420 Ma from the FAS suggests that the island arc existed at 420 Ma, indicating that the subduction of the Shangdan Ocean did not finish until the late Silurian. The DLLG deposits were mainly from basement material of the NQB, indicating that the Shangdan Ocean closed before the Middle Devonian, which implies that the NQB and South Qinling Belt (SQB) were spliced during the Early Devonian. This rapid transition from subduction to extension and the absence of molasse hint that no full orogeny occurred during the suture process and that the DLLG formed in a post-suture extensional rift basin.
{"title":"Provenance of the Devonian Liuling Group sandstones: Constraints on Paleozoic North–South China Block tectonics","authors":"Lei-Gang Zhang, Hong-Jun Qu, Peng Li","doi":"10.1016/j.jop.2025.100264","DOIUrl":"10.1016/j.jop.2025.100264","url":null,"abstract":"<div><div>The Devonian Liuling Group (DLLG) and its surrounding strata provide massive information about the Paleozoic subduction–suture–extension process of the North China Block (NCB) and South China Block (SCB). Systematic field-based sedimentology, sandstone modal composition, whole-rock elemental composition, and detrital zircon U–Pb dating were employed. The sedimentary sequence of DLLG shows that the water depth deepened and then shallowed, which is characteristic of an extensional basin. Analysis of the tectonic setting and geochronology revealed that the fore-arc sedimentary system (FAS) and DLLG were sourced from the North Qinling Belt (NQB) and NCB. An age population with a single peak at 420 Ma from the FAS suggests that the island arc existed at 420 Ma, indicating that the subduction of the Shangdan Ocean did not finish until the late Silurian. The DLLG deposits were mainly from basement material of the NQB, indicating that the Shangdan Ocean closed before the Middle Devonian, which implies that the NQB and South Qinling Belt (SQB) were spliced during the Early Devonian. This rapid transition from subduction to extension and the absence of molasse hint that no full orogeny occurred during the suture process and that the DLLG formed in a post-suture extensional rift basin.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100264"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144631768","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 : 2025-07-01DOI: 10.1016/j.jop.2025.100258
Zhuang-Zhuang Bai , Shu-Yuan Shi , Yong-Jie Hu , Wei Yang , Wu-Ren Xie , Wen-Zheng Li
The deeply buried (>4500 m) Cambrian Xixiangchi Formation in the Sichuan Basin, southwestern China, hosts significant reserves of natural gas. A comprehensive analysis combining petrographic, paleo-thermometric, geochemical, and petrophysical materials of the dolostone from the Xixiangchi Formation was conducted to provide insight into deeply buried carbonate reservoirs and decipher the complex diagenetic history. Dolomite-mudstone, fine-crystalline dolostone, and fine-crystalline dolomite cement of the Xixiangchi Formation underwent sabkha and reflux dolomitization. Medium- to coarse-crystalline dolostone, dolo-grainstone, and medium- to coarse-crystalline dolomite cements were then formed by burial dolomitization. These dolomites display δ13C ratios and REE patterns comparable to seawater, with progressively depleted δ18O ratios at greater burial depths. Dolo-grainstone originating from the platform shoal facies exhibits higher primary porosities and well-developed inter-particle pores compared to dolo-mudstone and crystalline dolostone lithologies, which are typically associated with the low-energy tidal flat and/or restricted platform environments. The initial spatial heterogeneity of primary porosity was subsequently modified by meteoric alteration and repeated episodes of dolomitization, which contributed to the development of secondary porosity. These processes increased the resistivity to compaction, and open fractures increased reservoir permeability. During the deep burial regime, saddle dolomite and calcite cements were precipitated at high fluid temperatures (up to 220 °C). Thermochemical sulfate reduction is characterized by the occurrence of anhydrite, hydrocarbon, and high homogenization temperatures and significantly low δ13C ratios (av.=−23.7‰) of calcite cements. Deep burial dissolution is significantly constrained by: corrosion of late diagenetic minerals, and the occurrence of bitumen in the center of pores. Mechanisms for the deep-burial dissolution include hydrothermal alteration and thermochemical sulfate reduction. This study indicates the complex diagenetic evolution of Cambrian Xixiangchi Formation, providing significant insights into global deep-burial carbonate reservoir potential.
{"title":"Dolomitization history and porosity evolution of the deeply buried Cambrian Xixiangchi Formation, Sichuan Basin, SW China","authors":"Zhuang-Zhuang Bai , Shu-Yuan Shi , Yong-Jie Hu , Wei Yang , Wu-Ren Xie , Wen-Zheng Li","doi":"10.1016/j.jop.2025.100258","DOIUrl":"10.1016/j.jop.2025.100258","url":null,"abstract":"<div><div>The deeply buried (>4500 m) Cambrian Xixiangchi Formation in the Sichuan Basin, southwestern China, hosts significant reserves of natural gas. A comprehensive analysis combining petrographic, paleo-thermometric, geochemical, and petrophysical materials of the dolostone from the Xixiangchi Formation was conducted to provide insight into deeply buried carbonate reservoirs and decipher the complex diagenetic history. Dolomite-mudstone, fine-crystalline dolostone, and fine-crystalline dolomite cement of the Xixiangchi Formation underwent sabkha and reflux dolomitization. Medium- to coarse-crystalline dolostone, dolo-grainstone, and medium- to coarse-crystalline dolomite cements were then formed by burial dolomitization. These dolomites display δ<sup>13</sup>C ratios and REE patterns comparable to seawater, with progressively depleted δ<sup>18</sup>O ratios at greater burial depths. Dolo-grainstone originating from the platform shoal facies exhibits higher primary porosities and well-developed inter-particle pores compared to dolo-mudstone and crystalline dolostone lithologies, which are typically associated with the low-energy tidal flat and/or restricted platform environments. The initial spatial heterogeneity of primary porosity was subsequently modified by meteoric alteration and repeated episodes of dolomitization, which contributed to the development of secondary porosity. These processes increased the resistivity to compaction, and open fractures increased reservoir permeability. During the deep burial regime, saddle dolomite and calcite cements were precipitated at high fluid temperatures (up to 220 °C). Thermochemical sulfate reduction is characterized by the occurrence of anhydrite, hydrocarbon, and high homogenization temperatures and significantly low δ<sup>13</sup>C ratios (av.=−23.7‰) of calcite cements. Deep burial dissolution is significantly constrained by: corrosion of late diagenetic minerals, and the occurrence of bitumen in the center of pores. Mechanisms for the deep-burial dissolution include hydrothermal alteration and thermochemical sulfate reduction. This study indicates the complex diagenetic evolution of Cambrian Xixiangchi Formation, providing significant insights into global deep-burial carbonate reservoir potential.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100258"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721250","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 : 2025-07-01DOI: 10.1016/j.jop.2025.04.001
Rahul Bailwal, Partha Pratim Chakraborty
An attempt has been made to document Microbially Induced Sedimentary Structure (MISS) from siliciclastic strata of the Nithar and Badalgarh Formations, Paleoproterozoic Raialo and Alwar groups of rocks in the Bayana Basin of NW India. Whereas in the Badalgarh Formation MISS are documented from shallow marine foreshore-upper shoreface succession, in the Nithar Formation, the features are recorded from fluvial deposits where the river system attained local stagnation. Unlike the dominant description of Precambrian shallow-marine MISS from sub-tidal settings, the present description highlights MISS from foreshore-upper shoreface deposits of the Badalgarh coastline. MISS are documented from field study (bedding surface) and are further proved by microscope study of thin sections. The bedding surface features include wrinkle marks, palimpsest ripple, patchy ripple, gas dome structure, desiccation cracks, and erosional remains, whereas under microscope, wavy crinkly microbial laminae with frayed edges, trapping of fine detritus in microbial filaments, flying paper effect and disseminations/clots of pyrite, in association, are documented. The biogenicity of the crinkly laminae is further checked by Raman Spectroscopy. The documented microbial structures are grouped under three categories, namely mat growth and stabilization, mat destruction, and mat burial. The Badalgarh coastline records shallowing-upward normal regressive depositional trend. In conjunction with earlier descriptions of MISS from Paleoproterzoic and Neoproterozoic successions of central and western India, the present study from northwest India establishes an overwhelming microbial influence on Precambrian siliciclastic sedimentation in Indian basins.
{"title":"Microbially induced sedimentary structures (MISS) from Paleoproterozoic siliciclastic successions and their bearing on shallow marine sedimentation: Bayana Basin, North Delhi Fold Belt, India","authors":"Rahul Bailwal, Partha Pratim Chakraborty","doi":"10.1016/j.jop.2025.04.001","DOIUrl":"10.1016/j.jop.2025.04.001","url":null,"abstract":"<div><div>An attempt has been made to document Microbially Induced Sedimentary Structure (MISS) from siliciclastic strata of the Nithar and Badalgarh Formations, Paleoproterozoic Raialo and Alwar groups of rocks in the Bayana Basin of NW India. Whereas in the Badalgarh Formation MISS are documented from shallow marine foreshore-upper shoreface succession, in the Nithar Formation, the features are recorded from fluvial deposits where the river system attained local stagnation. Unlike the dominant description of Precambrian shallow-marine MISS from sub-tidal settings, the present description highlights MISS from foreshore-upper shoreface deposits of the Badalgarh coastline. MISS are documented from field study (bedding surface) and are further proved by microscope study of thin sections. The bedding surface features include wrinkle marks, palimpsest ripple, patchy ripple, gas dome structure, desiccation cracks, and erosional remains, whereas under microscope, wavy crinkly microbial laminae with frayed edges, trapping of fine detritus in microbial filaments, flying paper effect and disseminations/clots of pyrite, in association, are documented. The biogenicity of the crinkly laminae is further checked by Raman Spectroscopy. The documented microbial structures are grouped under three categories, namely mat growth and stabilization, mat destruction, and mat burial. The Badalgarh coastline records shallowing-upward normal regressive depositional trend. In conjunction with earlier descriptions of MISS from Paleoproterzoic and Neoproterozoic successions of central and western India, the present study from northwest India establishes an overwhelming microbial influence on Precambrian siliciclastic sedimentation in Indian basins.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100253"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721246","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 manuscript provides valuable insight into the geological evolution of Central Kazakhstan during the Cenozoic and serves as a key tool for understanding the paleogeographic evolution of the surrounding regions. Based on the literature and the results of our own research, data on the Oligocene-Early Miocene fauna of the Askazansor site, located in the southern part of Central Kazakhstan, were analyzed and summarized. The stratigraphy was examined, the history of the research was studied, and an attempt was made to synchronize the paleofauna with other localities in Kazakhstan and Eurasia. The article presents descriptions of bone remains of previously unknown equids from here. The age of the deposits is considered to be the Early Miocene. Based on the study of mammals and the lithofacial analysis of sediments, conclusions were drawn about the paleoecological situation of this time.
{"title":"The Lower Miocene Askazansor Formation in Central Kazakhstan: Paleontological characteristics, biostratigraphy and paleogeographical conditions","authors":"Saida Nigmatova, Bolat Bayshashov, Ilnura Madiyarova, Arman Seidali, Balzhan Kalibek","doi":"10.1016/j.jop.2024.09.005","DOIUrl":"10.1016/j.jop.2024.09.005","url":null,"abstract":"<div><div>This manuscript provides valuable insight into the geological evolution of Central Kazakhstan during the Cenozoic and serves as a key tool for understanding the paleogeographic evolution of the surrounding regions. Based on the literature and the results of our own research, data on the Oligocene-Early Miocene fauna of the Askazansor site, located in the southern part of Central Kazakhstan, were analyzed and summarized. The stratigraphy was examined, the history of the research was studied, and an attempt was made to synchronize the paleofauna with other localities in Kazakhstan and Eurasia. The article presents descriptions of bone remains of previously unknown equids from here. The age of the deposits is considered to be the Early Miocene. Based on the study of mammals and the lithofacial analysis of sediments, conclusions were drawn about the paleoecological situation of this time.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100244"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720960","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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