Pub Date : 2024-10-01DOI: 10.1016/j.jop.2024.06.004
<div><div>Field-based sedimentology, state of the art facies analysis and sequence stratigraphic framework analysis have revealed the controls of local and global tectonics, basin-marginal slope, climate and changes in relative sea level (RSL) over the sedimentation pattern and evolution of a Neoproterozoic Kerur Formation within the Badami Group of Kaladgi Supergroup in India. The entire succession shows three major cycles of deposition. Facies study and fluvial architectural elemental analysis suggest considerable variations in depositional environments as well as palaeogeography. A transition from basin-margin alluvial cone deposits to braided system, initially with fluctuating ephemeral flows then to a steadier semi-perennial nature, is discernible within the 1<sup>st</sup> cycle, in response to decreasing depositional slope with rising water table. The initial alluvial cone and braided ephemeral streams of high slope areas is designated as a product of low accommodation systems tract (LAST), while the semi-perennial system with steadier flows, representing the axial river of the initial rift valley, appears to be a product of high – accommodation systems tract (HAST). The 2<sup>nd</sup> cycle begins with a perennial and steady braided river system and grades upward to a shallow marine succession, comprising wave-dominated, well-sorted sandstone, with a granular transgressive lag at the base. Thus, the bottommost fluvial interval of the 2<sup>nd</sup> cycle constitutes the lowstand systems tract (LST). The marine succession represents deposits of outer shelf offshore to foreshore-beach settings and is composed of an initially deepening and fining upward transgressive systems tract (TST), followed by a coarsening and shallowing upward highstand systems tract (HST) with a maximum marine flooding surface (MFS) in between, demarcated by a shale-rich condensed zone. The 3<sup>rd</sup> cycle, with its prograding alluvial fan and aggrading braided fluvial deposits and restricted occurrence, represents only the low accommodation systems tract (LAST) with a subaerial unconformity at the base. The basin evidently initiated in the western sector, followed by its eastward expansion during the first major rejuvenation of the basin margin faults, after the deposition of the 1<sup>st</sup> cycle. After the basin-wide deposition of the 2<sup>nd</sup> cycle, restricted development of the 3<sup>rd</sup> cycle took place in the western sector only, following the second major rejuvenation of the fault system. The proposed sedimentological model, supported by established geochronological constraints, suggests that the sedimentation in the 1<sup>st</sup> cycle begins with scree cones, alluvial fans and braided ephemeral channel networks, originated from faulted basin margins within a riftogenic setting possibly related to the global-scale extensional tectonics of Rodinia breakup. After the expansion of the basin, the marine inundation has been correlated to the tr
{"title":"Evolution of Neoproterozoic siliciclastic Kerur Formation in the light of sequence stratigraphic framework: Badami Basin, Karnataka, India","authors":"","doi":"10.1016/j.jop.2024.06.004","DOIUrl":"10.1016/j.jop.2024.06.004","url":null,"abstract":"<div><div>Field-based sedimentology, state of the art facies analysis and sequence stratigraphic framework analysis have revealed the controls of local and global tectonics, basin-marginal slope, climate and changes in relative sea level (RSL) over the sedimentation pattern and evolution of a Neoproterozoic Kerur Formation within the Badami Group of Kaladgi Supergroup in India. The entire succession shows three major cycles of deposition. Facies study and fluvial architectural elemental analysis suggest considerable variations in depositional environments as well as palaeogeography. A transition from basin-margin alluvial cone deposits to braided system, initially with fluctuating ephemeral flows then to a steadier semi-perennial nature, is discernible within the 1<sup>st</sup> cycle, in response to decreasing depositional slope with rising water table. The initial alluvial cone and braided ephemeral streams of high slope areas is designated as a product of low accommodation systems tract (LAST), while the semi-perennial system with steadier flows, representing the axial river of the initial rift valley, appears to be a product of high – accommodation systems tract (HAST). The 2<sup>nd</sup> cycle begins with a perennial and steady braided river system and grades upward to a shallow marine succession, comprising wave-dominated, well-sorted sandstone, with a granular transgressive lag at the base. Thus, the bottommost fluvial interval of the 2<sup>nd</sup> cycle constitutes the lowstand systems tract (LST). The marine succession represents deposits of outer shelf offshore to foreshore-beach settings and is composed of an initially deepening and fining upward transgressive systems tract (TST), followed by a coarsening and shallowing upward highstand systems tract (HST) with a maximum marine flooding surface (MFS) in between, demarcated by a shale-rich condensed zone. The 3<sup>rd</sup> cycle, with its prograding alluvial fan and aggrading braided fluvial deposits and restricted occurrence, represents only the low accommodation systems tract (LAST) with a subaerial unconformity at the base. The basin evidently initiated in the western sector, followed by its eastward expansion during the first major rejuvenation of the basin margin faults, after the deposition of the 1<sup>st</sup> cycle. After the basin-wide deposition of the 2<sup>nd</sup> cycle, restricted development of the 3<sup>rd</sup> cycle took place in the western sector only, following the second major rejuvenation of the fault system. The proposed sedimentological model, supported by established geochronological constraints, suggests that the sedimentation in the 1<sup>st</sup> cycle begins with scree cones, alluvial fans and braided ephemeral channel networks, originated from faulted basin margins within a riftogenic setting possibly related to the global-scale extensional tectonics of Rodinia breakup. After the expansion of the basin, the marine inundation has been correlated to the tr","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"13 4","pages":"Pages 706-737"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jop.2024.08.009
Olev Vinn , Jorge Colmenar , Samuel Zamora , Sofia Pereira , Gian Luigi Pillola , Abdullah A. Alkahtane , Saleh Al Farraj , Magdy El Hedeny
Seven Cornulites species, including a new one — Cornulites leonei n. sp., are described from the Upper Ordovician Portixeddu Formation (Katian, stage slices Ka2–3) of Sardinia and the Cavá (lower Katian, stage slice Ka2) and Estana (upper Katian, stage slices Ka3–4) formations of the Pyrenees. The Sardinian and Pyrenean cornulitids represent an adaptation to live in environments with high sedimentation rates and limited hard substrates availability. Their prominent annuli could have had a stabilizing function in the soft sediment that helped cornulitids to keep a favourable position in the sediment to enable suspension feeding. The known Late Ordovician cornulitid diversity in different Gondwana areas is low, usually ranging from one to three taxa, being higher (seven) in Sardinia. Like other benthic groups during the Late Ordovician, the cornulitid tubeworm faunas within the high-latitude peri-Gondwana Province indicate a certain endemism and share morphological and ecological affinities, such as a small body size and tubes with a strikingly small apical angle. Although essentially endemic, some links with cornulitids from the Late Ordovician of Scotland are revealed.
{"title":"Late Ordovician cornulitid tubeworms from high-latitude peri-Gondwana (Sardinia and the Pyrenees) and their palaeobiogeographic significance","authors":"Olev Vinn , Jorge Colmenar , Samuel Zamora , Sofia Pereira , Gian Luigi Pillola , Abdullah A. Alkahtane , Saleh Al Farraj , Magdy El Hedeny","doi":"10.1016/j.jop.2024.08.009","DOIUrl":"10.1016/j.jop.2024.08.009","url":null,"abstract":"<div><div>Seven <em>Cornulites</em> species, including a new one — <em>Cornulites leonei</em> n. sp., are described from the Upper Ordovician Portixeddu Formation (Katian, stage slices Ka2–3) of Sardinia and the Cavá (lower Katian, stage slice Ka2) and Estana (upper Katian, stage slices Ka3–4) formations of the Pyrenees. The Sardinian and Pyrenean cornulitids represent an adaptation to live in environments with high sedimentation rates and limited hard substrates availability. Their prominent annuli could have had a stabilizing function in the soft sediment that helped cornulitids to keep a favourable position in the sediment to enable suspension feeding. The known Late Ordovician cornulitid diversity in different Gondwana areas is low, usually ranging from one to three taxa, being higher (seven) in Sardinia. Like other benthic groups during the Late Ordovician, the cornulitid tubeworm faunas within the high-latitude peri-Gondwana Province indicate a certain endemism and share morphological and ecological affinities, such as a small body size and tubes with a strikingly small apical angle. Although essentially endemic, some links with cornulitids from the Late Ordovician of Scotland are revealed.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"13 4","pages":"Pages 939-953"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jop.2024.08.008
Gang Liu , Guo-Zhi Wang , Na Li , Hong-Ling He , Nan-Nan Lu , Qing Lei , Zi-Ang Wang
Anomalously positive δ13C values in ancient dolomites are very rare. Dark gray argillaceous rocks of the lacustrine sediments of the Permian Lucaogou Formation are important source rocks in the Junggar Basin, and dolomites of varying thicknesses from 10 cm to 150 cm are often interspersed in argillaceous rocks. Based on the study of petrographic sections, this paper systematically analyzes the carbon and oxygen isotopes of dolomite and discusses the causes of abnormally high carbon isotope values and their significance in reconstructing paleoenvironment and paleoclimate. The results show that carbon isotope values are abnormally high in the dolomite of Lucaogou Formation, and the δ13C value is between +3.2 ‰ PDB and +19.6‰ PDB, with an average of +9.7‰ PDB. The δ18O values range from -17.4‰ PDB to -1.7‰ PDB, with an average of -8.1‰ PDB. From the lower part to the upper part of the Lucaogou Formation, the carbon isotope value gradually increases and becomes increasingly positive, and the carbon isotope of the dolomite deposited near the shore is more positive than that of the dolomite deposited far from the shore. The anomalously positive δ13C of the dolomite is mainly caused by microbial methanogenesis, with some contribution from evaporation. Microorganisms are mainly distributed at the redox interface. Evaporation controls the salinity and fluctuation of the redox interface in sedimentary water. The positive deviation difference in carbon isotopes between nearshore and offshore sedimentary dolomites may be related to the location of the redox interface during deposition. Together, the petrographic features and carbon and oxygen isotope signatures of the sections reflect the gradual evolution of the paleolake from a hydrologically open environment to a hydrologically closed one and the possible transition of the paleoclimate from a relatively warm to an arid condition, which is possibly a geochemical response to global climate change in the Permian period.
{"title":"Characteristics and geological significance of carbon and oxygen isotopes of the Permian Lucaogou Formation dolomite in the southern Junggar Basin, northwestern China","authors":"Gang Liu , Guo-Zhi Wang , Na Li , Hong-Ling He , Nan-Nan Lu , Qing Lei , Zi-Ang Wang","doi":"10.1016/j.jop.2024.08.008","DOIUrl":"10.1016/j.jop.2024.08.008","url":null,"abstract":"<div><div>Anomalously positive δ<sup>13</sup>C values in ancient dolomites are very rare. Dark gray argillaceous rocks of the lacustrine sediments of the Permian Lucaogou Formation are important source rocks in the Junggar Basin, and dolomites of varying thicknesses from 10 cm to 150 cm are often interspersed in argillaceous rocks. Based on the study of petrographic sections, this paper systematically analyzes the carbon and oxygen isotopes of dolomite and discusses the causes of abnormally high carbon isotope values and their significance in reconstructing paleoenvironment and paleoclimate. The results show that carbon isotope values are abnormally high in the dolomite of Lucaogou Formation, and the δ<sup>13</sup>C value is between +3.2 ‰ PDB and +19.6‰ PDB, with an average of +9.7‰ PDB. The δ<sup>18</sup>O values range from -17.4‰ PDB to -1.7‰ PDB, with an average of -8.1‰ PDB. From the lower part to the upper part of the Lucaogou Formation, the carbon isotope value gradually increases and becomes increasingly positive, and the carbon isotope of the dolomite deposited near the shore is more positive than that of the dolomite deposited far from the shore. The anomalously positive δ<sup>13</sup>C of the dolomite is mainly caused by microbial methanogenesis, with some contribution from evaporation. Microorganisms are mainly distributed at the redox interface. Evaporation controls the salinity and fluctuation of the redox interface in sedimentary water. The positive deviation difference in carbon isotopes between nearshore and offshore sedimentary dolomites may be related to the location of the redox interface during deposition. Together, the petrographic features and carbon and oxygen isotope signatures of the sections reflect the gradual evolution of the paleolake from a hydrologically open environment to a hydrologically closed one and the possible transition of the paleoclimate from a relatively warm to an arid condition, which is possibly a geochemical response to global climate change in the Permian period.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"13 4","pages":"Pages 862-882"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jop.2024.06.006
Peatlands have obvious carbon storage capacity and are crucial in mitigating global climate change. As the end-product of peatlands, coals have preserved a large amount of palaeoenvironmental information. The carbon accumulation rate and the net primary productivity (NPP) of coal-forming peatlands can be used as proxies for recovering palaeoenvironments. A super-thick coal seam (42°35′N, 91°25′E) was developed in the Middle Jurassic Xishanyao Formation in the Shaerhu coalfield in the southern margin of the Tuha (Turpan-Hami) Basin, northwestern China. In this study, we use the time series analysis to identify the periods of Milankovitch orbital cycles in the Gamma-ray curve of this super-thick (124.85 m) coal and then use the obtained cycle periods of 405 ka, 173 ka, 44 ka, 37.6 ka, 22.5 ka to calculate the timeframe of the coal-forming peatlands which ranges from 2703.44 to 2975.11 ka. Considering that the carbon content of the coal seam is 78.32% and the carbon loss during the coalification is about 25.80%, the carbon accumulation rate of the targeted coal seam is estimated to be 58.47–64.34 g C/m2·a, and the NPP is estimated to be 252.28–277.63 g C/m2·a. The main palaeoenvironmental factors controlling the NPP of peatlands are CO2 content, palaeolatitude and palaeotemperature. The reduced NPP values of the palaeo-peatlands in the Shaerhu coalfield can be attributed to the mid-palaeolatitude and/or too low atmospheric CO2 contents. To a certain extent, the NPP of palaeo-peatlands reflects the changes in atmospheric CO2, which can further reveal the dynamic response of the global carbon cycle to climate change. Therefore, predicting the level of NPP in the Middle Jurassic and studying the final destination of carbon in the ecosystem are beneficial to understanding the coal-forming process and palaeoenvironment.
泥炭地具有明显的碳储存能力，对减缓全球气候变化至关重要。作为泥炭地的最终产物，煤炭保存了大量的古环境信息。成煤泥炭地的碳积累率和净初级生产力（NPP）可作为复原古环境的代用指标。中国西北吐哈（吐鲁番-哈密）盆地南缘沙尔湖煤田中侏罗世西山窑地层发育有超厚煤层（42°35′N，91°25′E）。本研究通过时间序列分析，确定了该超厚（124.85 m）煤层伽马射线曲线中的米兰科维奇轨道周期，并利用所得到的405 ka、173 ka、44 ka、37.6 ka、22.5 ka周期，计算出该煤层形成泥炭地的时间范围为2703.44-2975.11 ka。考虑到煤层的含碳量为 78.32%，煤化过程中的碳损失约为 25.80%，估算目标煤层的碳积累率为 58.47-64.34 g C/m-a，NPP 为 252.28-277.63 g C/m-a。控制泥炭地 NPP 的主要古环境因素是 CO 含量、古纬度和古温度。沙尔湖煤田古泥炭地NPP值的降低可归因于中古纬度和/或过低的大气CO含量。古高原NPP在一定程度上反映了大气CO的变化，可以进一步揭示全球碳循环对气候变化的动态响应。因此，预测中侏罗世的NPP水平，研究生态系统中碳的最终去向，有利于了解成煤过程和古环境。
{"title":"Extensive carbon cycle between peatland and vegetation: Insights from high net primary productivity of the Middle Jurassic in northwestern China","authors":"","doi":"10.1016/j.jop.2024.06.006","DOIUrl":"10.1016/j.jop.2024.06.006","url":null,"abstract":"<div><div>Peatlands have obvious carbon storage capacity and are crucial in mitigating global climate change. As the end-product of peatlands, coals have preserved a large amount of palaeoenvironmental information. The carbon accumulation rate and the net primary productivity (NPP) of coal-forming peatlands can be used as proxies for recovering palaeoenvironments. A super-thick coal seam (42°35′N, 91°25′E) was developed in the Middle Jurassic Xishanyao Formation in the Shaerhu coalfield in the southern margin of the Tuha (Turpan-Hami) Basin, northwestern China. In this study, we use the time series analysis to identify the periods of Milankovitch orbital cycles in the Gamma-ray curve of this super-thick (124.85 m) coal and then use the obtained cycle periods of 405 ka, 173 ka, 44 ka, 37.6 ka, 22.5 ka to calculate the timeframe of the coal-forming peatlands which ranges from 2703.44 to 2975.11 ka. Considering that the carbon content of the coal seam is 78.32% and the carbon loss during the coalification is about 25.80%, the carbon accumulation rate of the targeted coal seam is estimated to be 58.47–64.34 g C/m<sup>2</sup>·a, and the NPP is estimated to be 252.28–277.63 g C/m<sup>2</sup>·a. The main palaeoenvironmental factors controlling the NPP of peatlands are CO<sub>2</sub> content, palaeolatitude and palaeotemperature. The reduced NPP values of the palaeo-peatlands in the Shaerhu coalfield can be attributed to the mid-palaeolatitude and/or too low atmospheric CO<sub>2</sub> contents. To a certain extent, the NPP of palaeo-peatlands reflects the changes in atmospheric CO<sub>2</sub>, which can further reveal the dynamic response of the global carbon cycle to climate change. Therefore, predicting the level of NPP in the Middle Jurassic and studying the final destination of carbon in the ecosystem are beneficial to understanding the coal-forming process and palaeoenvironment.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"13 4","pages":"Pages 1016-1028"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141552496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jop.2024.08.007
Ayush Srivastava , Sudipta Dasgupta , Seema Singh
The Chhasra Formation (CF) of Kutch Basin exemplifies a typical mixed siliciclastic-carbonate system with alternations of biostromal carbonate and fine-grained siliciclastic beds. The CF is subdivided into two members: the lower Claystone (CM) and the upper Siltstone (SM) member. Three CM outcrops (P1-P3) comprising buried palaeosols that formed under a specific environmental set-up involving imperfectly to poorly drained conditions, are exposed along the Berwali River. The biostromal carbonate beds, alternating with the palaeosols, contain invertebrate bioclasts (bivalves, gastropods, echinoids, etc.) and are characterized by a paucispecific firmground Thalassinoides ichnofabric. At section P1, below the contact between the underlying palaeosol and overlying carbonate, Thalassinoides transforms into firmground Gyrolithes inside the palaeosol forming a compound ichnotaxon. The palaeosol intervals of sections P1 and P2 consist of a Vondrichnus‒Termitichnus‒root trace ichnofabric defining the Termitichnus ichnofacies. At section P3, lenses of fully bioturbated siltstones with a monospecific firmground Thalassinoides ichnofabric can be observed within an overall silty palaeosol horizon, thereby, locally cross-cutting the pedogenic features. The ichnofabrics of section P3 indicate polyphase pedogenesis with three stages: (1) initial stage: pedogenesis in siltstone of undefined depositional affinity which was obscured by pedogenic processes, (2) transient stage: recurring marine incursions and colonization by crustaceans within the lens-shaped palaeotopographic depressions overprinting the palaeosol, and (3) final stage: subaerial exposure and another preserved phase of pedogenesis. The CM shows an apparent low-order T–R (transgressive-regressive) cyclicity within a 3rd-order TST (transgressive systems tract) that is supported by pedogenic intensity, ichnofabrics, and reciprocal sedimentation near the Miocene basin margin, though the cyclicity can be the result of both autogenic and/or lower-order allogenic changes.
{"title":"Lower-order transgressive–regressive cycles within a higher-order transgression at the basin margin: an aberrant intercalation of palaeosol and biostromal ichnofabrics from the early Miocene Kutch Basin, India","authors":"Ayush Srivastava , Sudipta Dasgupta , Seema Singh","doi":"10.1016/j.jop.2024.08.007","DOIUrl":"10.1016/j.jop.2024.08.007","url":null,"abstract":"<div><div>The Chhasra Formation (CF) of Kutch Basin exemplifies a typical mixed siliciclastic-carbonate system with alternations of biostromal carbonate and fine-grained siliciclastic beds. The CF is subdivided into two members: the lower Claystone (CM) and the upper Siltstone (SM) member. Three CM outcrops (P1-P3) comprising buried palaeosols that formed under a specific environmental set-up involving imperfectly to poorly drained conditions, are exposed along the Berwali River. The biostromal carbonate beds, alternating with the palaeosols, contain invertebrate bioclasts (bivalves, gastropods, echinoids, etc.) and are characterized by a paucispecific firmground <em>Thalassinoides</em> ichnofabric. At section P1, below the contact between the underlying palaeosol and overlying carbonate, <em>Thalassinoides</em> transforms into firmground <em>Gyrolithes</em> inside the palaeosol forming a compound ichnotaxon. The palaeosol intervals of sections P1 and P2 consist of a <em>Vondrichnus</em>‒<em>Termitichnus</em>‒root trace ichnofabric defining the <em>Termitichnus</em> ichnofacies. At section P3, lenses of fully bioturbated siltstones with a monospecific firmground <em>Thalassinoides</em> ichnofabric can be observed within an overall silty palaeosol horizon, thereby, locally cross-cutting the pedogenic features. The ichnofabrics of section P3 indicate polyphase pedogenesis with three stages: (1) initial stage: pedogenesis in siltstone of undefined depositional affinity which was obscured by pedogenic processes, (2) transient stage: recurring marine incursions and colonization by crustaceans within the lens-shaped palaeotopographic depressions overprinting the palaeosol, and (3) final stage: subaerial exposure and another preserved phase of pedogenesis. The CM shows an apparent low-order T–R (transgressive-regressive) cyclicity within a 3rd-order TST (transgressive systems tract) that is supported by pedogenic intensity, ichnofabrics, and reciprocal sedimentation near the Miocene basin margin, though the cyclicity can be the result of both autogenic and/or lower-order allogenic changes.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"13 4","pages":"Pages 906-923"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jop.2024.08.001
Gisella M. Della Costa, Guillermo L. Albanesi
One of the largest Ordovician sea-level rises is the Evae transgression, which occurs in the lower part of the Oepikodus evae Biozone, indicative of a late Floian age. Specifically, the characteristics associated with the highstand of this event included: a higher proportion of specimens of the index species O. evae than other species, a diversity acme in the evae Biozone, and a reduction of biogeographic barriers that resulted in a high proportion of species with cosmopolitan distribution. In the present contribution, the pattern of species similarity among Laurentia, Argentine Precordillera, Baltica, Kazakhstania, South China, and Australia is evaluated with a multiple coefficient analysis including only the sections that recorded the highstand of the Evae transgression. Moreover, the effect of possible terrestrial, latitudinal, physicochemical barriers and palaeogeographic distance on the species distribution is statistically analysed. Our results show a global pattern of conodont species distribution that is highly constrained by the tested palaeoenvironmental factors. This suggests that contrary to what was expected for a prominent transgression, faunal barriers did not decrease significantly during the Evae drowning peak.
{"title":"Global pattern of conodont similarity and faunal constraints during the highstand of the Evae eustatic event (late Floian, Lower Ordovician)","authors":"Gisella M. Della Costa, Guillermo L. Albanesi","doi":"10.1016/j.jop.2024.08.001","DOIUrl":"10.1016/j.jop.2024.08.001","url":null,"abstract":"<div><div>One of the largest Ordovician sea-level rises is the Evae transgression, which occurs in the lower part of the <em>Oepikodus evae</em> Biozone, indicative of a late Floian age. Specifically, the characteristics associated with the highstand of this event included: a higher proportion of specimens of the index species <em>O. evae</em> than other species, a diversity acme in the <em>evae</em> Biozone, and a reduction of biogeographic barriers that resulted in a high proportion of species with cosmopolitan distribution. In the present contribution, the pattern of species similarity among Laurentia, Argentine Precordillera, Baltica, Kazakhstania, South China, and Australia is evaluated with a multiple coefficient analysis including only the sections that recorded the highstand of the Evae transgression. Moreover, the effect of possible terrestrial, latitudinal, physicochemical barriers and palaeogeographic distance on the species distribution is statistically analysed. Our results show a global pattern of conodont species distribution that is highly constrained by the tested palaeoenvironmental factors. This suggests that contrary to what was expected for a prominent transgression, faunal barriers did not decrease significantly during the Evae drowning peak.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"13 4","pages":"Pages 883-905"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jop.2024.06.002
The Cenomanian-Turonian boundary oceanic anoxic event (OAE-2; Bonarelli event; ∼94 Ma) is associated with a species turnover in the marine calcareous microfossil record, widespread marine anoxia, black shale deposition and positive δ13C excursions. This study reviews 141 CTBE sites globally, aiming to understand micropaleontological, geochemical, and sedimentological expressions of OAE-2. There is a clear palaeogeographic and palaeobathymetric heterogeneity in the development of OAE-2 marine anoxia. A majority of the documented OAE-2 sites are from deep marine environments. The calcareous nannoplankton and benthic foraminifera record a diversity decline, while planktic foraminifera shows community level shifts and no major mass extinction. The variability of total organic carbon in OAE-2 sediments across sites (<1 to >10 wt. %) and the δ13C profiles (diachronous) have been attributed to different mechanisms of anoxia development. The increased primary “productivity model” gains support from productivity proxies (e.g., Ba, P, Cu, Ni), redox-sensitive elements (e.g., Mn, Mo, U, V, As), and eutrophic genera (e.g., benthic foraminifera Gabonita spp., calcareous nannofossils Biscutum spp. and Zeugrhabdotus erectus). The enhanced organic carbon “preservation model” in stratified (semi) restricted basins gains support from sites with lower enrichment of redox-sensitive elements and oligotrophic flora and fauna in the OAE-2 records. Geochronology of the Caribbean and the High Atlantic Large Igneous Province events (CLIP and HALIP) mark them as likely triggers of the OAE-2 related global perturbation of marine biogeochemistry. Volcanic triggers may have caused climate warming, altered hydrological cycles, enhanced continental weathering, shifts in ocean circulation, and nutrient flows. Addressing knowledge gaps, further research is urged, utilizing innovative proxies, and exploring underrepresented depositional systems to comprehensively understand OAE-2 onset and biotic crisis.
{"title":"Spatio-temporal variability in microfossil and geochemical records of Cenomanian-Turonian oceanic anoxic event-2: a review","authors":"","doi":"10.1016/j.jop.2024.06.002","DOIUrl":"10.1016/j.jop.2024.06.002","url":null,"abstract":"<div><div>The Cenomanian-Turonian boundary oceanic anoxic event (OAE-2; Bonarelli event; ∼94 Ma) is associated with a species turnover in the marine calcareous microfossil record, widespread marine anoxia, black shale deposition and positive δ<sup>13</sup>C excursions. This study reviews 141 CTBE sites globally, aiming to understand micropaleontological, geochemical, and sedimentological expressions of OAE-2. There is a clear palaeogeographic and palaeobathymetric heterogeneity in the development of OAE-2 marine anoxia. A majority of the documented OAE-2 sites are from deep marine environments. The calcareous nannoplankton and benthic foraminifera record a diversity decline, while planktic foraminifera shows community level shifts and no major mass extinction. The variability of total organic carbon in OAE-2 sediments across sites (<1 to >10 wt. %) and the δ<sup>13</sup>C profiles (diachronous) have been attributed to different mechanisms of anoxia development. The increased primary “productivity model” gains support from productivity proxies (e.g., Ba, P, Cu, Ni), redox-sensitive elements (e.g., Mn, Mo, U, V, As), and eutrophic genera (e.g., benthic foraminifera <em>Gabonita</em> spp., calcareous nannofossils <em>Biscutum</em> spp. and <em>Zeugrhabdotus</em> erectus). The enhanced organic carbon “preservation model” in stratified (semi) restricted basins gains support from sites with lower enrichment of redox-sensitive elements and oligotrophic flora and fauna in the OAE-2 records. Geochronology of the Caribbean and the High Atlantic Large Igneous Province events (CLIP and HALIP) mark them as likely triggers of the OAE-2 related global perturbation of marine biogeochemistry. Volcanic triggers may have caused climate warming, altered hydrological cycles, enhanced continental weathering, shifts in ocean circulation, and nutrient flows. Addressing knowledge gaps, further research is urged, utilizing innovative proxies, and exploring underrepresented depositional systems to comprehensively understand OAE-2 onset and biotic crisis.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"13 4","pages":"Pages 646-674"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141401880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jop.2024.07.003
Miao Yu , Gang Gao , Miao Liu , Hui Liang , Ji-Lun Kang , Xiong-Fei Xu , Xin-Ying Zhao
The second member of the Lucaogou Formation (P2l2) in the Tiaohu and Malang Sags of the Santanghu Basin (study area) underwent periodic volcanic activity and frequent lithological changes. This study comprehensively analyzed the organic geochemistry, mineral composition, organic matter (OM) types, volcanic cycle, and palaeoenvironment of shale in the study area. Techniques such as total organic carbon (TOC), rock pyrolysis (Rock-Eval), organic petrology, scanning electron microscopy (SEM) with energy-dispersive spectrum (EDS) analysis, X-ray diffraction (XRD), trace elements, and saturated hydrocarbon gas chromatography and mass spectrometry (GC–MS) were employed. The findings suggest that limited terrigenous input during the sedimentary period of the P2l2 led to the deposition of a distinctive mixture of volcanic ash (felsic) and carbonate (dolomite and calcite), with a low average clay mineral content of 6%. The P2l2 shale emerged as a high-quality source rock, predominantly composed of type I and II kerogens, with moderate OM maturity. The deposition environment was characterized by hot and arid conditions, high salinity, and intensive reducibility, which was favorable for algae development and conducive to OM preservation. Notably, two lamalginite types, labeled as lamalginite “A” and lamalginite “B,” were identified. Lamalginite “B”-rich shales were deposited in a hotter and drier climate compared to lamalginite “A”-rich shales. Lamalginite “B”- rich shale inexhibited high levels of C28 regular sterane and β-carotenes, distinguishing it from lamalginite “A”-rich shale. A comprehensive analysis involving organic petrology, SEM, sedimentary environment, and biomarker characteristics suggests that lamalginite “B” may be a salt-tolerant green alga, while lamalginite “A” may be a cyanobacterium. Finally, an OM enrichment model for the P2l2 shale was established.
三塘湖盆地（研究区）蕉湖、马栏沙组卢草沟地层第二系（P2l2）经历了周期性的火山活动，岩性变化频繁。本研究全面分析了研究区页岩的有机地球化学、矿物组成、有机质（OM）类型、火山周期和古环境。研究采用了总有机碳（TOC）、岩石热解（Rock-Eval）、有机岩石学、扫描电子显微镜（SEM）与能量色散光谱（EDS）分析、X射线衍射（XRD）、微量元素和饱和碳氢化合物气相色谱-质谱（GC-MS）等技术。研究结果表明，在 P2l2 的沉积时期，有限的陆相沉积导致火山灰（长石）和碳酸盐（白云石和方解石）的独特混合物沉积，粘土矿物的平均含量较低，仅为 6%。P2l2 页岩是一种优质原岩，主要由 I 型和 II 型角砾岩组成，OM 成熟度适中。沉积环境的特点是炎热干旱、盐度高、还原性强，有利于藻类的生长，也有利于 OM 的保存。值得注意的是，发现了两种薄片岩类型，分别称为薄片岩 "A "和薄片岩 "B"。与富含片麻岩 "A "的页岩相比，富含片麻岩 "B "的页岩沉积在更炎热、更干燥的气候中。富含薄片岩 "B "的页岩中含有大量的 C28 正甾烷和 β-胡萝卜素，这使其有别于富含薄片岩 "A "的页岩。一项涉及有机岩石学、扫描电镜、沉积环境和生物标记特征的综合分析表明，薄片岩 "B "可能是一种耐盐绿藻，而薄片岩 "A "可能是一种蓝藻。最后，建立了 P2l2 页岩的 OM 富集模型。
{"title":"Sedimentary environment shift and organic matter enrichment mechanism in response to volcanic ash influence: A case study of the Permian Lucaogou Formation, Santanghu Basin, NW China","authors":"Miao Yu , Gang Gao , Miao Liu , Hui Liang , Ji-Lun Kang , Xiong-Fei Xu , Xin-Ying Zhao","doi":"10.1016/j.jop.2024.07.003","DOIUrl":"10.1016/j.jop.2024.07.003","url":null,"abstract":"<div><div>The second member of the Lucaogou Formation (P<sub>2</sub>l<sub>2</sub>) in the Tiaohu and Malang Sags of the Santanghu Basin (study area) underwent periodic volcanic activity and frequent lithological changes. This study comprehensively analyzed the organic geochemistry, mineral composition, organic matter (OM) types, volcanic cycle, and palaeoenvironment of shale in the study area. Techniques such as total organic carbon (TOC), rock pyrolysis (Rock-Eval), organic petrology, scanning electron microscopy (SEM) with energy-dispersive spectrum (EDS) analysis, X-ray diffraction (XRD), trace elements, and saturated hydrocarbon gas chromatography and mass spectrometry (GC–MS) were employed. The findings suggest that limited terrigenous input during the sedimentary period of the P<sub>2</sub>l<sub>2</sub> led to the deposition of a distinctive mixture of volcanic ash (felsic) and carbonate (dolomite and calcite), with a low average clay mineral content of 6%. The P<sub>2</sub>l<sub>2</sub> shale emerged as a high-quality source rock, predominantly composed of type I and II kerogens, with moderate OM maturity. The deposition environment was characterized by hot and arid conditions, high salinity, and intensive reducibility, which was favorable for algae development and conducive to OM preservation. Notably, two lamalginite types, labeled as lamalginite “A” and lamalginite “B,” were identified. Lamalginite “B”-rich shales were deposited in a hotter and drier climate compared to lamalginite “A”-rich shales. Lamalginite “B”- rich shale inexhibited high levels of C<sub>28</sub> regular sterane and β-carotenes, distinguishing it from lamalginite “A”-rich shale. A comprehensive analysis involving organic petrology, SEM, sedimentary environment, and biomarker characteristics suggests that lamalginite “B” may be a salt-tolerant green alga, while lamalginite “A” may be a cyanobacterium. Finally, an OM enrichment model for the P<sub>2</sub>l<sub>2</sub> shale was established.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"13 4","pages":"Pages 793-822"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141699379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jop.2024.09.001
Zhi-Qiang Feng , Qian Li , Wei Han , Kun-Yuan Ma , Yong-Jiang Liu , Rong-Zhu Wei , Yan-Wei Du , Yong Lei , Guang-Hui Li
The Taiyuan Basin is of importance for intraplate tectonic deformation in North China and contains Cenozoic strata with a maximum thickness of 3800 m. A ∼853.5-m-deep borehole (ZK01) with an overall core recovery rate of 85.09% was drilled at Yuci (37°35′37ʺN, 112°39′47ʺE) in the central Taiyuan Basin, to obtain high-resolution records of paleomagnetism, paleoclimatic and paleoenvironmental conditions, and depositional environment of the sediments. The obtained magnetic polarity sequence consists of 13 normal and 12 reverse zones, which correspond to C1n–C4An.2n of the geomagnetic polarity time scale. Magnetostratigraphic data show that the evolution of ZK01 core covers the interval from 8.1 Ma to the present, and the bottoms of Pliocene, Quaternary, and Middle Pleistocene were identified in Taiyuan Basin, with a sedimentary accumulation rate ranging from 62.5 m/Ma to 175.9 m/Ma. Geochemical data reveal that the source rocks in the study area underwent intense weathering and the sediments mainly formed in a semi-arid and oxygen-rich conditions. In addition, paleoclimatic changes occurred at ∼7 Ma, 3.8 Ma, and 1.7 Ma, which can be closely related to the tectonic uplift of the Loess Plateau and Tibetan Plateau, as well as the variations in the Asian monsoon and associated regional and global climatic change.
{"title":"Magnetostratigraphy and paleoenvironmental record of late Cenozoic sediments in the Taiyuan Basin, North China","authors":"Zhi-Qiang Feng , Qian Li , Wei Han , Kun-Yuan Ma , Yong-Jiang Liu , Rong-Zhu Wei , Yan-Wei Du , Yong Lei , Guang-Hui Li","doi":"10.1016/j.jop.2024.09.001","DOIUrl":"10.1016/j.jop.2024.09.001","url":null,"abstract":"<div><div>The Taiyuan Basin is of importance for intraplate tectonic deformation in North China and contains Cenozoic strata with a maximum thickness of 3800 m. A ∼853.5-m-deep borehole (ZK01) with an overall core recovery rate of 85.09% was drilled at Yuci (37°35′37ʺN, 112°39′47ʺE) in the central Taiyuan Basin, to obtain high-resolution records of paleomagnetism, paleoclimatic and paleoenvironmental conditions, and depositional environment of the sediments. The obtained magnetic polarity sequence consists of 13 normal and 12 reverse zones, which correspond to C1n–C4An.2n of the geomagnetic polarity time scale. Magnetostratigraphic data show that the evolution of ZK01 core covers the interval from 8.1 Ma to the present, and the bottoms of Pliocene, Quaternary, and Middle Pleistocene were identified in Taiyuan Basin, with a sedimentary accumulation rate ranging from 62.5 m/Ma to 175.9 m/Ma. Geochemical data reveal that the source rocks in the study area underwent intense weathering and the sediments mainly formed in a semi-arid and oxygen-rich conditions. In addition, paleoclimatic changes occurred at ∼7 Ma, 3.8 Ma, and 1.7 Ma, which can be closely related to the tectonic uplift of the Loess Plateau and Tibetan Plateau, as well as the variations in the Asian monsoon and associated regional and global climatic change.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"13 4","pages":"Pages 971-992"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jop.2024.07.002
Guo-Liang Xie , Gao-Jie Zhou , Yu-Yong Sun , Yan-Ran Hu , Wei-Duo Hao
The extensive bedded cherts deposited during the Ediacaran–Cambrian (E–C) transition period play a crucial role in understanding the geological evolution of this period, yet the origin of these cherts remains disputed. Here, we present new geochemical data for cherts of the Piyuancun (PYC) Formation deposited during the Late Ediacaran and the Hetang (HT) Formation deposited during the Early Cambrian in northern Jiangxi region, Lower Yangtze region, South China. The PYC cherts contain a small amount of monaxons sponge spicules and radiolarian fragments, while the HT cherts lack siliceous organism evidence. Major and trace element analysis, coupled with discriminant diagrams, indicate a possible shift in redox conditions of seawater during the E–C transition in the northern Jiangxi region. The shift suggests a change from weakly–moderately restricted euxinic conditions to strongly restricted euxinic conditions. Furthermore, the location of both cherts are distant from the source area of siliceous organisms. Fossil evidence, as well as the values of Fe/Ti and Fe/(Mn+Ti), Eu anomalies, Post-Archean Australian Shale (PAAS) normalized REE+Y patterns, and various discriminant diagrams, support the conclusion that the PYC and HT cherts originated primarily from direct seawater precipitation, with the PYC cherts exhibiting weak hydrothermal evidence. Upwelling contributes to the formation of HT cherts and organic matter (OM) accumulation. Ocean acidification, triggered by OM degradation and biodegradation processes during the E–C transition period, leads to the extensive silica precipitation and preservation. These results enhance our understanding of the geological processes during the E–C transition.
{"title":"Geochemistry of cherts from the northern Jiangxi region, South China: Implication for paleoenvironment","authors":"Guo-Liang Xie , Gao-Jie Zhou , Yu-Yong Sun , Yan-Ran Hu , Wei-Duo Hao","doi":"10.1016/j.jop.2024.07.002","DOIUrl":"10.1016/j.jop.2024.07.002","url":null,"abstract":"<div><div>The extensive bedded cherts deposited during the Ediacaran–Cambrian (E–C) transition period play a crucial role in understanding the geological evolution of this period, yet the origin of these cherts remains disputed. Here, we present new geochemical data for cherts of the Piyuancun (PYC) Formation deposited during the Late Ediacaran and the Hetang (HT) Formation deposited during the Early Cambrian in northern Jiangxi region, Lower Yangtze region, South China. The PYC cherts contain a small amount of monaxons sponge spicules and radiolarian fragments, while the HT cherts lack siliceous organism evidence. Major and trace element analysis, coupled with discriminant diagrams, indicate a possible shift in redox conditions of seawater during the E–C transition in the northern Jiangxi region. The shift suggests a change from weakly–moderately restricted euxinic conditions to strongly restricted euxinic conditions. Furthermore, the location of both cherts are distant from the source area of siliceous organisms. Fossil evidence, as well as the values of Fe/Ti and Fe/(Mn+Ti), Eu anomalies, Post-Archean Australian Shale (PAAS) normalized REE+Y patterns, and various discriminant diagrams, support the conclusion that the PYC and HT cherts originated primarily from direct seawater precipitation, with the PYC cherts exhibiting weak hydrothermal evidence. Upwelling contributes to the formation of HT cherts and organic matter (OM) accumulation. Ocean acidification, triggered by OM degradation and biodegradation processes during the E–C transition period, leads to the extensive silica precipitation and preservation. These results enhance our understanding of the geological processes during the E–C transition.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"13 4","pages":"Pages 823-838"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141610351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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