The phased uplift of the Tibetan Plateau since the Cenozoic strongly changed the Asian topography and greatly impacted not only the regional but also the global climate. Being sensitive to past climate changes, fossil plants are proven pivotal bio-indicators that can infer the paleoclimate and paleoelevation of different Tibetan Plateau parts. However, the timing and mechanisms of the uplift in the northeastern Tibetan Plateau remain debated due to limited evidence from plant fossils and inconsistent results. In this investigation, Pueraria leaflet and pod fossils collected from the Miocene Upper Youshashan Formation of the Wulan Basin, northeastern Tibetan Plateau, are reported. The leaflet fossils are assigned as a new species: Pueraria qinghaiensis Zhen-Dong Cao et San-Ping Xie sp. nov., while P. montana is recognized as its nearest living relative; the pod fossils are assigned as Pueraria sp. The leaflet margins of P. qinghaiensis and other fossils found in the same layer indicate that Pueraria from the Wulan Basin likely lived in open habitats and sprawled at the waterside. Moreover, the climate of the basin apparently was warm and humid in the Middle Miocene, and the elevation was about 723–2398 m based on the ecological niche of Pueraria. The occurrence of these new Pueraria fossils from the Wulan Basin supports the view that the elevation of the northeastern Tibetan Plateau did not attain its present elevation during the Middle Miocene. Subsequently, the plateau's uplift caused a series of environmental transformations, including increased elevation, reduced temperature and precipitation, and the intensification of Asian monsoons, which altogether led to the regional disappearance of the Pueraria population in the Wulan Basin.
{"title":"A moderate elevation and warm-humid climate of the Wulan Basin, NE Tibetan Plateau in the Middle Miocene indicated by Pueraria macrofossils","authors":"Zhen-Dong Cao, San-Ping Xie, Li-Ming Liu, Xiao-Mei Li, Si-Hang Zhang, Yun-Zhe Zhang, De-Fei Yan","doi":"10.1016/j.jop.2024.08.012","DOIUrl":"10.1016/j.jop.2024.08.012","url":null,"abstract":"<div><div>The phased uplift of the Tibetan Plateau since the Cenozoic strongly changed the Asian topography and greatly impacted not only the regional but also the global climate. Being sensitive to past climate changes, fossil plants are proven pivotal bio-indicators that can infer the paleoclimate and paleoelevation of different Tibetan Plateau parts. However, the timing and mechanisms of the uplift in the northeastern Tibetan Plateau remain debated due to limited evidence from plant fossils and inconsistent results. In this investigation, <em>Pueraria</em> leaflet and pod fossils collected from the Miocene Upper Youshashan Formation of the Wulan Basin, northeastern Tibetan Plateau, are reported. The leaflet fossils are assigned as a new species: <em>Pueraria qinghaiensis</em> Zhen-Dong Cao et San-Ping Xie sp. nov., while <em>P. montana</em> is recognized as its nearest living relative; the pod fossils are assigned as <em>Pueraria</em> sp. The leaflet margins of <em>P. qinghaiensis</em> and other fossils found in the same layer indicate that <em>Pueraria</em> from the Wulan Basin likely lived in open habitats and sprawled at the waterside. Moreover, the climate of the basin apparently was warm and humid in the Middle Miocene, and the elevation was about 723–2398 m based on the ecological niche of <em>Pueraria</em>. The occurrence of these new <em>Pueraria</em> fossils from the Wulan Basin supports the view that the elevation of the northeastern Tibetan Plateau did not attain its present elevation during the Middle Miocene. Subsequently, the plateau's uplift caused a series of environmental transformations, including increased elevation, reduced temperature and precipitation, and the intensification of Asian monsoons, which altogether led to the regional disappearance of the <em>Pueraria</em> population in the Wulan Basin.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 413-430"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868998","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 : 2025-04-01DOI: 10.1016/j.jop.2025.01.001
Erik Ramirez-Montoya , Jayagopal Madhavaraju , Rogelio Monreal , Luigi Solari
The sedimentary succession of the El Antimonio Group, which unconformably overlies the Permian (Guadalupian) Monos Formation, is well exposed in the Sierra del Álamo section, southwest of Caborca, Sonora, México. Here, this section is composed of the Triassic Santa Eduwiges (renamed from the previous Antimonio Formation) and Río Asunción and the Lower Jurassic Sierra de Santa Rosa formations. This study focuses on the provenance and geochronology of the Triassic formations. The sandstone of Santa Eduwiges and Rio Asuncion formations are classified from litharenite to arkose. On the QtFL diagram, sandstone samples plot in the orogenic, transitional continental and undissected arc fields. In contrast, on the QmFLt diagram, the samples are mainly concentrated in the mixed, transitional continental and quartzose recycled fields. Main zircon populations identified in this study are Triassic, Permian and Proterozoic. Proterozoic zircon grains are grouped into ∼1.8, 1.7, 1.6, 1.4 and 1.1 Ga populations whose primary sources are the crustal basement rocks of the Mojave Yavapai and Mazatzal provinces of southwestern North America, and Mesoproterozoic granitic plutons that intrude them. Permo-Triassic zircon grains may be sourced in magmatic arc rocks of this age that in southwestern North America is well presented in northwestern Sonora. The detrital zircon dated allows us to constrain maximum depositional ages for the Triassic Santa Eduwiges Formation of the El Antimonio Group: the youngest zircon grains from lowermost part (Sequence I) yielded an age of 252.64±1.98 Ma; zircon grains from its middle part (Sequence IV) yielded an age of 244.63±3.04 Ma and zircon grains from Sequence VI of the upper part of this unit yielded an age of 229.33±1.72 Ma. The El Antimonio Group was deposited in a forearc basin located south as a product of the Permo-Triassic continental magmatic arc that contributed much of the detritus to the early Triassic basin. During later stages of sedimentation in the Triassic basin, detritus was mostly sourced from the Proterozoic basement rocks.
El Antimonio群的沉积序列不整合地覆盖在二叠纪（Guadalupian） Monos组上，在Sierra del Álamo剖面，Sonora, Caborca, m xico。该剖面由三叠纪Santa Eduwiges（从之前的Antimonio组改名）、Río Asunción和下侏罗统Sierra de Santa Rosa组组成。本文重点研究了三叠纪地层的物源和年代学。Santa Eduwiges组和里约热内卢Asuncion组砂岩分为岩屑岩-粗砂岩。在QtFL图上，砂岩样品分布在造山带、过渡大陆带和未剖分弧域中。相比之下，在QmFLt图上，样品主要集中在混合、过渡大陆和石英回收场。本研究确定的主要锆石种群为三叠纪、二叠纪和元古代。元古代锆石颗粒分为~ 1.8、1.7、1.6、1.4和1.1 Ga群，其主要来源是北美西南部Mojave Yavapai和Mazatzal省的地壳基底岩，以及侵入它们的中元古代花岗质岩体。二叠-三叠纪的锆石颗粒可能来源于北美西南部索诺拉西北部的岩浆弧岩。碎屑锆石年代确定了El Antimonio群三叠系Santa Eduwiges组的最大沉积年龄：最下部（层序I）最年轻的锆石颗粒年龄为252.64±1.98 Ma；中段（层序IV）锆石年龄为244.63±3.04 Ma，上部（层序VI）锆石年龄为229.33±1.72 Ma。El Antimonio群是二叠纪-三叠纪大陆岩浆弧的产物，沉积于位于南部的弧前盆地，该岩浆弧为早三叠纪盆地贡献了大量碎屑。三叠纪盆地沉积后期，碎屑岩主要来源于元古界基底岩。
{"title":"Depositional age and provenance of Triassic sedimentary succession from Northwestern México: Evidence from petrography and detrital zircon U–Pb geochronology","authors":"Erik Ramirez-Montoya , Jayagopal Madhavaraju , Rogelio Monreal , Luigi Solari","doi":"10.1016/j.jop.2025.01.001","DOIUrl":"10.1016/j.jop.2025.01.001","url":null,"abstract":"<div><div>The sedimentary succession of the El Antimonio Group, which unconformably overlies the Permian (Guadalupian) Monos Formation, is well exposed in the Sierra del Álamo section, southwest of Caborca, Sonora, México. Here, this section is composed of the Triassic Santa Eduwiges (renamed from the previous Antimonio Formation) and Río Asunción and the Lower Jurassic Sierra de Santa Rosa formations. This study focuses on the provenance and geochronology of the Triassic formations. The sandstone of Santa Eduwiges and Rio Asuncion formations are classified from litharenite to arkose. On the QtFL diagram, sandstone samples plot in the orogenic, transitional continental and undissected arc fields. In contrast, on the QmFLt diagram, the samples are mainly concentrated in the mixed, transitional continental and quartzose recycled fields. Main zircon populations identified in this study are Triassic, Permian and Proterozoic. Proterozoic zircon grains are grouped into ∼1.8, 1.7, 1.6, 1.4 and 1.1 Ga populations whose primary sources are the crustal basement rocks of the Mojave Yavapai and Mazatzal provinces of southwestern North America, and Mesoproterozoic granitic plutons that intrude them. Permo-Triassic zircon grains may be sourced in magmatic arc rocks of this age that in southwestern North America is well presented in northwestern Sonora. The detrital zircon dated allows us to constrain maximum depositional ages for the Triassic Santa Eduwiges Formation of the El Antimonio Group: the youngest zircon grains from lowermost part (Sequence I) yielded an age of 252.64±1.98 Ma; zircon grains from its middle part (Sequence IV) yielded an age of 244.63±3.04 Ma and zircon grains from Sequence VI of the upper part of this unit yielded an age of 229.33±1.72 Ma. The El Antimonio Group was deposited in a forearc basin located south as a product of the Permo-Triassic continental magmatic arc that contributed much of the detritus to the early Triassic basin. During later stages of sedimentation in the Triassic basin, detritus was mostly sourced from the Proterozoic basement rocks.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 370-390"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Middle Permian extinction event is considered one of the most devastating events of all Phanerozoic biotic crises, yet it is not fully understood and has attracted a lot of controversial comments. This event is found at the end of the Capitanian carbonate strata in the Ruteh Formation (late Wordian–Capitanian) at the Alborz Mountains in Iran. It is characterized by the decimation of marine organisms, particularly calcareous algae and microproblematic fossils. The current study attempts to interpret the cause of this crisis in the framework of astronomically-forced climatic changes. Based on cyclostratigraphy analysis, the evidence of the Milankovitch cycles, including long eccentricity, short eccentricity, obliquity, and precession are recorded in the Ruteh Formation succession. The establishment of a floating astronomical time scale using the long eccentricity cycles led to an estimation of a duration of 1.6 and 2.43 million years for the Wordian and Capitanian stages, respectively. Integrated facies studies and a sedimentary noise model indicate that the Ruteh Formation is composed of three ∼1.2 Myr sequences, corresponding to third-order sequences, and ten 405-kyr sequences, corresponding to fourth-to fifth-order sequences. The boundaries of the ∼1.2 Myr sequences indicate regression in sea level and low sedimentation rate. Considering the paleogeographic situation of the Alborz Mountains, the sedimentation of the Ruteh Formation in the Middle Permian was affected by the Inter-Tropical Convergence Zone and interactions between the ocean and atmosphere during the Pangea assemblage, leading to an increase in temperature. With the sum of these observations, we conclude that factors such as high temperature and a decrease in sedimentation rate created unfavorable conditions for the mentioned biota at the end of the Capitanian.
{"title":"Astronomical forces as a potential cause for the end-guadalupian biotic crisis: A case study from central Alborz, Iran","authors":"Forough Abasaghi , Rui Zhang , Qing-Yong Luo , Ren Wei","doi":"10.1016/j.jop.2024.12.007","DOIUrl":"10.1016/j.jop.2024.12.007","url":null,"abstract":"<div><div>The Middle Permian extinction event is considered one of the most devastating events of all Phanerozoic biotic crises, yet it is not fully understood and has attracted a lot of controversial comments. This event is found at the end of the Capitanian carbonate strata in the Ruteh Formation (late Wordian–Capitanian) at the Alborz Mountains in Iran. It is characterized by the decimation of marine organisms, particularly calcareous algae and microproblematic fossils. The current study attempts to interpret the cause of this crisis in the framework of astronomically-forced climatic changes. Based on cyclostratigraphy analysis, the evidence of the Milankovitch cycles, including long eccentricity, short eccentricity, obliquity, and precession are recorded in the Ruteh Formation succession. The establishment of a floating astronomical time scale using the long eccentricity cycles led to an estimation of a duration of 1.6 and 2.43 million years for the Wordian and Capitanian stages, respectively. Integrated facies studies and a sedimentary noise model indicate that the Ruteh Formation is composed of three ∼1.2 Myr sequences, corresponding to third-order sequences, and ten 405-kyr sequences, corresponding to fourth-to fifth-order sequences. The boundaries of the ∼1.2 Myr sequences indicate regression in sea level and low sedimentation rate. Considering the paleogeographic situation of the Alborz Mountains, the sedimentation of the Ruteh Formation in the Middle Permian was affected by the Inter-Tropical Convergence Zone and interactions between the ocean and atmosphere during the Pangea assemblage, leading to an increase in temperature. With the sum of these observations, we conclude that factors such as high temperature and a decrease in sedimentation rate created unfavorable conditions for the mentioned biota at the end of the Capitanian.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 603-628"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869267","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 : 2025-04-01DOI: 10.1016/j.jop.2024.11.005
Jin-Yi Wang, Zhen-Kui Jin, Hao Cheng, Ke-Bei Hua, Hao-Xuan Ran
Various studies have indicated that microbes were involved in the precipitation of dolostones in the Proterozoic. The identification of ancient microbial dolostones remains challenging due to the rare preservation of microbe fossils. In this study, we found ancient microbial dolostones in Paleoproterozoic Chuanlinggou Formation in Beijing, North China, employing thin-section observations, trace and rare earth elements as well as carbon and oxygen isotope analyses to reveal the origin. The paleoenvironment has also been reconstructed. The results indicate that dolostones found in the Chuanlinggou Formation are formed through primary dolomite precipitation induced by cyanobacterial activity. These dolomitized geobodies exhibit various morphologies of mounded, banded and bedded, and all dolostones are microcrystalline textures. The geochemical characteristics of these dolostones show a relatively low δ18O value (average = −7.34‰), Fe(II) enrichment, Ce anomaly and comparable patterns of REY. The specific geomorphology (mounded, banded and bedded) and mottled structures of the dolostones indicate that they are formed through in-situ dolomite precipitation induced by cyanobacterial activity. The high Fe(II) content suggests a reducing environment, whereas the Ce anomaly indicates anoxic conditions within the water body. The REY patterns provide evidence for the microbial origin of the dolostones. These dolostones were formed in clastic off-shore shelf environments. The seawater was warm, normal in salinity, and the sea floor was slightly agitated to quiet and reducing. The geomorphology of the dolomitized geobodies changes from mounded to banded and bedded in correlation with depth increase and hydrodynamic energy decrease. This study may provide another type of environments for microbial dolostones and the geochemical characteristics of these dolostones may serve as a valuable reference for identifying similar ancient microbial dolostones.
{"title":"Origin and depositional environments of mounded, banded and bedded dolostones in the clastic deposits of the Paleoproterozoic Chuanlinggou Formation in Beijing, North China","authors":"Jin-Yi Wang, Zhen-Kui Jin, Hao Cheng, Ke-Bei Hua, Hao-Xuan Ran","doi":"10.1016/j.jop.2024.11.005","DOIUrl":"10.1016/j.jop.2024.11.005","url":null,"abstract":"<div><div>Various studies have indicated that microbes were involved in the precipitation of dolostones in the Proterozoic. The identification of ancient microbial dolostones remains challenging due to the rare preservation of microbe fossils. In this study, we found ancient microbial dolostones in Paleoproterozoic Chuanlinggou Formation in Beijing, North China, employing thin-section observations, trace and rare earth elements as well as carbon and oxygen isotope analyses to reveal the origin. The paleoenvironment has also been reconstructed. The results indicate that dolostones found in the Chuanlinggou Formation are formed through primary dolomite precipitation induced by cyanobacterial activity. These dolomitized geobodies exhibit various morphologies of mounded, banded and bedded, and all dolostones are microcrystalline textures. The geochemical characteristics of these dolostones show a relatively low δ<sup>18</sup>O value (average = −7.34‰), Fe(II) enrichment, Ce anomaly and comparable patterns of REY. The specific geomorphology (mounded, banded and bedded) and mottled structures of the dolostones indicate that they are formed through in-situ dolomite precipitation induced by cyanobacterial activity. The high Fe(II) content suggests a reducing environment, whereas the Ce anomaly indicates anoxic conditions within the water body. The REY patterns provide evidence for the microbial origin of the dolostones. These dolostones were formed in clastic off-shore shelf environments. The seawater was warm, normal in salinity, and the sea floor was slightly agitated to quiet and reducing. The geomorphology of the dolomitized geobodies changes from mounded to banded and bedded in correlation with depth increase and hydrodynamic energy decrease. This study may provide another type of environments for microbial dolostones and the geochemical characteristics of these dolostones may serve as a valuable reference for identifying similar ancient microbial dolostones.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 629-650"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869268","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 : 2025-04-01DOI: 10.1016/j.jop.2025.02.002
Jun-Jie Wang , En-Pu Gong , Yong-Li Zhang , Wen-Tao Huang , Xiao Li , Li-Fu Wang , Guan-Ming Lai , De-Peng Li
The well-preserved reproductive morphology of Eugonophyllum within Pennsylvanian algal deposits in Guizhou Province, South China, provides a unique opportunity to study phylloid algal ecology and its role in carbonate buildups. Vegetative reproduction, characterized by the branching growth of algal segments followed by lateral budding in young thalli, appears to be the primary mechanism for maintaining and continuously increasing the population in the community. This method provides a dense, stable framework and bioclastic sediments for the development of lateral growth. Sexual reproduction occurs among mature thalli (comprising approximately 5%–10% of the population) and is characterized by synchronous gamete release. The synchronous spawning periodically increases the population and controls reef growth by the superposition of alternating generations. The combined effects of intrinsic factors of phylloid algae (rapid growth and reproductive strategy) and extrinsic factors (nutrient availability, ocean chemistry, seawater temperature) contributed to the dominance of phylloid algae in reef ecosystems in tropical-subtropical regions during the Pennsylvanian. Detailed evidence of Eugonophyllum growth and reproduction reveals the widespread distribution and high productivity of phylloid algae, opening new insights into global algal reef ecosystem blooms.
{"title":"The role of algal reproduction in phylloid algal buildups: a case study in Pennsylvanian phylloid algae in southern Guizhou, China","authors":"Jun-Jie Wang , En-Pu Gong , Yong-Li Zhang , Wen-Tao Huang , Xiao Li , Li-Fu Wang , Guan-Ming Lai , De-Peng Li","doi":"10.1016/j.jop.2025.02.002","DOIUrl":"10.1016/j.jop.2025.02.002","url":null,"abstract":"<div><div>The well-preserved reproductive morphology of <em>Eugonophyllum</em> within Pennsylvanian algal deposits in Guizhou Province, South China, provides a unique opportunity to study phylloid algal ecology and its role in carbonate buildups. Vegetative reproduction, characterized by the branching growth of algal segments followed by lateral budding in young thalli, appears to be the primary mechanism for maintaining and continuously increasing the population in the community. This method provides a dense, stable framework and bioclastic sediments for the development of lateral growth. Sexual reproduction occurs among mature thalli (comprising approximately 5%–10% of the population) and is characterized by synchronous gamete release. The synchronous spawning periodically increases the population and controls reef growth by the superposition of alternating generations. The combined effects of intrinsic factors of phylloid algae (rapid growth and reproductive strategy) and extrinsic factors (nutrient availability, ocean chemistry, seawater temperature) contributed to the dominance of phylloid algae in reef ecosystems in tropical-subtropical regions during the Pennsylvanian. Detailed evidence of <em>Eugonophyllum</em> growth and reproduction reveals the widespread distribution and high productivity of phylloid algae, opening new insights into global algal reef ecosystem blooms.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 664-678"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869270","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 : 2025-04-01DOI: 10.1016/j.jop.2025.01.004
Eduardo Mayoral , Antonio Rodríguez Ramírez , Jérémy Duveau , Ricardo Díaz-Delgado , Juan Antonio Morales , Eloísa Bernáldez Sánchez , Esteban García-Viñas , Ana Santos , Mili Jiménez Melero , Milagros Alzaga , Ignacio Díaz-Martínez
The southern of the Iberian Peninsula preserves a diverse ichnological record of vertebrates from the late Neogene–Quaternary. While the ages of several tracksites, such as those from the Miocene–Pliocene transition and the middle-late Pleistocene, are well-established, others remain undated or have unknown ages. This paper reports the discovery of the southernmost tracksite in the Iberian Peninsula and continental Europe on the Island of Tarifa (Cádiz). The tracksite contains over 600 vertebrate footprints from the early Pleistocene that are grouped in four morphotypes. Morphotypes 1, 2 and 3 (M1, M2 and M3) are predominantly didactyl-shaped, rounded to ovoid and elongated, and associated with tracks left by artiodactyls. Morphotype 4 (M4), suboval to subcircular in outline, is the largest and is probably related to the imprint left by proboscideans.
We also document the progressive transition from morphotype 2 with isolated, rounded footprints to morphotype 3 with elongated tracks formed by overlapping two tracks of the same animal which is observed. The consistency of the substrate, together with the trackmaker limb dynamics, conditioned the final morphology of the tracks, which were produced in a very soft clay-rich substrate of late Oligocene, that was folded and tilted in the latest Pliocene. This relief configuration gave rise to a narrow, partially or totally flooded corridor through which the trackmaker animals passed continuously, simultaneously, and in opposite ways. This discovery from the southernmost tip of continental Europe is the first one from the early Pleistocene in the Iberian Peninsula and a rare example from the Mediterranean region.
{"title":"Early Pleistocene vertebrate tracks impressed on Oligocene beds from the southernmost Iberian Peninsula: Palaeogeographic implications","authors":"Eduardo Mayoral , Antonio Rodríguez Ramírez , Jérémy Duveau , Ricardo Díaz-Delgado , Juan Antonio Morales , Eloísa Bernáldez Sánchez , Esteban García-Viñas , Ana Santos , Mili Jiménez Melero , Milagros Alzaga , Ignacio Díaz-Martínez","doi":"10.1016/j.jop.2025.01.004","DOIUrl":"10.1016/j.jop.2025.01.004","url":null,"abstract":"<div><div>The southern of the Iberian Peninsula preserves a diverse ichnological record of vertebrates from the late Neogene–Quaternary. While the ages of several tracksites, such as those from the Miocene–Pliocene transition and the middle-late Pleistocene, are well-established, others remain undated or have unknown ages. This paper reports the discovery of the southernmost tracksite in the Iberian Peninsula and continental Europe on the Island of Tarifa (Cádiz). The tracksite contains over 600 vertebrate footprints from the early Pleistocene that are grouped in four morphotypes. Morphotypes 1, 2 and 3 (M1, M2 and M3) are predominantly didactyl-shaped, rounded to ovoid and elongated, and associated with tracks left by artiodactyls. Morphotype 4 (M4), suboval to subcircular in outline, is the largest and is probably related to the imprint left by proboscideans.</div><div>We also document the progressive transition from morphotype 2 with isolated, rounded footprints to morphotype 3 with elongated tracks formed by overlapping two tracks of the same animal which is observed. The consistency of the substrate, together with the trackmaker limb dynamics, conditioned the final morphology of the tracks, which were produced in a very soft clay-rich substrate of late Oligocene, that was folded and tilted in the latest Pliocene. This relief configuration gave rise to a narrow, partially or totally flooded corridor through which the trackmaker animals passed continuously, simultaneously, and in opposite ways. This discovery from the southernmost tip of continental Europe is the first one from the early Pleistocene in the Iberian Peninsula and a rare example from the Mediterranean region.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 315-333"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869228","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 : 2025-04-01DOI: 10.1016/j.jop.2025.03.002
Yu-Lan Li , Giovanni Mussini , Li-Jun Zhang , Si-Cun Song , Ming Li , Ling Zhong , Feng Tang
The fossil record of the latest Ediacaran and earliest Cambrian comprises diverse tubular and ribbon-like macrofossils of uncertain affinities, some of which could record early metazoans and macroalgae. This study compares two ribbon-like macrofossils typical of Ediacaran–Cambrian intervals, investigating their morphology, potential affinities, and biostratigraphic significance: Rugosusivitta, preserved as essentially two-dimensional carbonaceous compressions, and Harlaniella, preserved as casts and molds. It is shown that the recently described Rugosusivitta orthogonia Tang et al., 2021 resembles the tube-like Harlaniella ingriana in its morphology, characterized by a combination of transverse ridges and longitudinal stripes separated into distinct parts of an elongate body. This combination of features challenges algal or protistan affinities, leaving open the possibility of metazoan origins. Both Rugosusivitta and Harlaniella likely represent body fossils rather than ichnofossils consistent with their preservation as either carbonaceous compressions or sediment-infilled tubes, respectively. By reconstructing the global distribution of Rugosusivitta and Harlaniella in different taphonomic windows, we suggest that these fossils record a coherent morphotype spanning the Ediacaran–Cambrian boundary.
埃迪卡拉纪晚期和寒武纪早期的化石记录包括多种管状和带状大型化石，亲缘关系不确定，其中一些可能记录了早期后生动物和大型藻类。本研究比较了埃迪卡拉-寒武纪两个典型的带状大化石，研究了它们的形态、潜在的亲缘关系和生物地层意义：Rugosusivitta，基本上作为二维碳质压缩物保存，Harlaniella，作为铸件和模具保存。研究表明，最近描述的Rugosusivitta orthogonia Tang et al.， 2021在形态上类似于管状的Harlaniella ingriana，其特征是横向脊和纵向条纹的组合，这些条纹被分成细长身体的不同部分。这种特征的结合挑战了藻类或原生生物的亲和力，留下了后生动物起源的可能性。Rugosusivitta和Harlaniella都可能代表了身体化石而不是鱼化石，这与它们分别作为碳质压缩物或沉积物填充管的保存方式一致。通过对Rugosusivitta和Harlaniella在不同分类窗口的全球分布进行重建，我们认为这些化石记录了一个跨越埃迪卡拉-寒武纪边界的连贯形态型。
{"title":"Two ribbon-like macrofossils in contrasting preservational styles from the Ediacaran–Cambrian interval","authors":"Yu-Lan Li , Giovanni Mussini , Li-Jun Zhang , Si-Cun Song , Ming Li , Ling Zhong , Feng Tang","doi":"10.1016/j.jop.2025.03.002","DOIUrl":"10.1016/j.jop.2025.03.002","url":null,"abstract":"<div><div>The fossil record of the latest Ediacaran and earliest Cambrian comprises diverse tubular and ribbon-like macrofossils of uncertain affinities, some of which could record early metazoans and macroalgae. This study compares two ribbon-like macrofossils typical of Ediacaran–Cambrian intervals, investigating their morphology, potential affinities, and biostratigraphic significance: <em>Rugosusivitta</em>, preserved as essentially two-dimensional carbonaceous compressions, and <em>Harlaniella,</em> preserved as casts and molds. It is shown that the recently described <em>Rugosusivitta orthogonia</em> Tang et al., 2021 resembles the tube-like <em>Harlaniella ingriana</em> in its morphology, characterized by a combination of transverse ridges and longitudinal stripes separated into distinct parts of an elongate body. This combination of features challenges algal or protistan affinities, leaving open the possibility of metazoan origins. Both <em>Rugosusivitta</em> and <em>Harlaniella</em> likely represent body fossils rather than ichnofossils consistent with their preservation as either carbonaceous compressions or sediment-infilled tubes, respectively. By reconstructing the global distribution of <em>Rugosusivitta</em> and <em>Harlaniella</em> in different taphonomic windows, we suggest that these fossils record a coherent morphotype spanning the Ediacaran–Cambrian boundary.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 651-663"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869269","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 : 2025-04-01DOI: 10.1016/j.jop.2025.01.003
Ming-Cheng Liu , Sheng-He Wu , Da-Li Yue , Zhen-Hua Xu , Xiao-Long Wan , Hong-Li Wu , Zhao-Hui Chen , Zhen Li
Lacustrine gravity-flow deposits have enormous hydrocarbon potential. However, their depositional architecture has long been considered very complicated and is controlled by various factors, making petroleum exploration and development highly challenging. The influence of palaeogeomorphology on the extent and formation mechanisms of lacustrine gravity-flow deposits remains poorly understood. This study uses 3D seismic data, well-log data, and core data to characterize the palaeogeomorphology and depositional architecture of the lacustrine gravity-flow deposit of the Yanchang Formation in the Ordos Basin, while analyzing the influence of palaeogeomorphology on the architecture, distribution, and evolution of lacustrine gravity-flow deposit systems. The results showed that three palaeogeomorphologic units—shelf, slope, and basin floor—developed in the basin. Gravity-flow deposits can be further divided into channel and lobe systems. Gravity-flow channel systems have developed in the upper slope area, which include three types of architectural elements: confined channels, unconfined channels, and levee-overbank. As the transport distance of gravity flow increases, the erosion ability of gravity flow weakens, resulting in the terrain formed by gravity flow erosion gradually weakening the constraint on sediment transport. Consequently, gravity-driven flow pathways shift from linear, confined channels to curved, unconfined channels, finally leading to the development of numerous distributary channels. In the lower slope area, gravity flow sediments distribute rapidly and accumulate to form lobes after encountering slope breaks, due to the decrease of dynamics, including three types of architectural elements: distributary channels, lobe axis and lobe fringe. These lobes are tongue-shaped and fan-shaped on the plane. A series of lobes are superimposed and form a lobe complex set. These lobe complex sets are distributed in a branch-like manner. There are many branch-shaped low-bend amplitude channels inside the lobe complex set. Palaeogeomorphology plays an important role in controlling the spatial distribution of depositional architecture. As the slope gradient increases, the influence of slope break on sediment gravity flow weakens, leading to a delay of the sediment gravity flow slumping to the basin bottom. Additionally, the extension length of the channel system on the slope increases. Furthermore, the extension length of the lobes toward the center of the basin also increases. This work improves the fundamental understanding of the depositional architecture of lacustrine gravity-flow deposits and may help enhance sand prediction for the same type deposit reservoirs.
{"title":"Palaeogeomorphological control on the depositional architecture of lacustrine gravity-flow deposits in a depression lacustrine basin: a case study of the Triassic Yanchang Formation, southern Ordos Basin, China","authors":"Ming-Cheng Liu , Sheng-He Wu , Da-Li Yue , Zhen-Hua Xu , Xiao-Long Wan , Hong-Li Wu , Zhao-Hui Chen , Zhen Li","doi":"10.1016/j.jop.2025.01.003","DOIUrl":"10.1016/j.jop.2025.01.003","url":null,"abstract":"<div><div>Lacustrine gravity-flow deposits have enormous hydrocarbon potential. However, their depositional architecture has long been considered very complicated and is controlled by various factors, making petroleum exploration and development highly challenging. The influence of palaeogeomorphology on the extent and formation mechanisms of lacustrine gravity-flow deposits remains poorly understood. This study uses 3D seismic data, well-log data, and core data to characterize the palaeogeomorphology and depositional architecture of the lacustrine gravity-flow deposit of the Yanchang Formation in the Ordos Basin, while analyzing the influence of palaeogeomorphology on the architecture, distribution, and evolution of lacustrine gravity-flow deposit systems. The results showed that three palaeogeomorphologic units—shelf, slope, and basin floor—developed in the basin. Gravity-flow deposits can be further divided into channel and lobe systems. Gravity-flow channel systems have developed in the upper slope area, which include three types of architectural elements: confined channels, unconfined channels, and levee-overbank. As the transport distance of gravity flow increases, the erosion ability of gravity flow weakens, resulting in the terrain formed by gravity flow erosion gradually weakening the constraint on sediment transport. Consequently, gravity-driven flow pathways shift from linear, confined channels to curved, unconfined channels, finally leading to the development of numerous distributary channels. In the lower slope area, gravity flow sediments distribute rapidly and accumulate to form lobes after encountering slope breaks, due to the decrease of dynamics, including three types of architectural elements: distributary channels, lobe axis and lobe fringe. These lobes are tongue-shaped and fan-shaped on the plane. A series of lobes are superimposed and form a lobe complex set. These lobe complex sets are distributed in a branch-like manner. There are many branch-shaped low-bend amplitude channels inside the lobe complex set. Palaeogeomorphology plays an important role in controlling the spatial distribution of depositional architecture. As the slope gradient increases, the influence of slope break on sediment gravity flow weakens, leading to a delay of the sediment gravity flow slumping to the basin bottom. Additionally, the extension length of the channel system on the slope increases. Furthermore, the extension length of the lobes toward the center of the basin also increases. This work improves the fundamental understanding of the depositional architecture of lacustrine gravity-flow deposits and may help enhance sand prediction for the same type deposit reservoirs.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 476-500"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869314","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 : 2025-04-01DOI: 10.1016/j.jop.2025.03.001
Xiao-Fei Feng , Xiao-Ming Zhao , Massine Bouchakour , Xi Zhang , Jia-Wang Ge , Yue-Li Liang , Chang-Cheng Yang
Cyclostratigraphic studies enable to reconstruct the geological timescales of many marine formations. However, these investigations are still lacking a precise astronomical tuning in lacustrine environments, particularly in the Middle Jurassic, due to the paucity of biological traces and the lack of data. In this study, detailed spectral analyses of natural gamma ray (GR) logging data were conducted on the lacustrine Sha-1 member from two wells in the Sichuan Basin, southwestern China. Core data samples were calibrated to test the lithological changes for proceeding with cyclostratigraphic analysis with more confidence. The spectral analysis and evolutionary spectral analysis of the GR logs reveal that the wavelength ratios of the stratigraphic cycles are ∼20:5:2:1, being consistent with the period ratios of astronomical cycles (long eccentricity, short eccentricity, obliquity, and precession). Correlation coefficient (COCO) analyses were applied to quantitatively measure the fitting of the witnessed sedimentary cycles to astronomical periods and provide a possible sedimentation rate range. The results show that astronomical time scale of the studied interval comprises 58.4–60.6 m cycles, representing the 405 kyr eccentricity cycles, and 14.9–16.6 m cycles, representing the ∼100 kyr eccentricity cycles. This study reveals a ∼2.43 Myr duration for the Sha-1 member. Sedimentary noise modeling reveals that long-term million-year period (1.2 Myr) astronomical forcing may have been a significant driver of lake-level changes in the Sichuan Basin. Moreover, high-frequency (405 kyr scale) lake-level variations associated with the mid-term base-level cycles (4th-order sequences) were linked to climato-eustatic changes. This study suggests comparison between parameters of cyclostratigraphic records and sequence stratigraphic base-level cycles in lacustrine sediments. The stratigraphic surfaces of mid-term base-level cycles correspond to minima ∼405 kyr-long eccentricity cycle curve and high values of DYNOT (dynamic noise after orbital tuning). Integrating cyclostratigraphy with the base-level cycles is, therefore, a vital approach for defining the short-term oscillations of lake-level, and proved to be a useful tool for characterizing thin-bedded lacustrine reservoirs.
{"title":"Cyclostratigraphy of the Middle Jurassic Aalenian Sha-1 member lacustrine record in central Sichuan Basin, southwestern China","authors":"Xiao-Fei Feng , Xiao-Ming Zhao , Massine Bouchakour , Xi Zhang , Jia-Wang Ge , Yue-Li Liang , Chang-Cheng Yang","doi":"10.1016/j.jop.2025.03.001","DOIUrl":"10.1016/j.jop.2025.03.001","url":null,"abstract":"<div><div>Cyclostratigraphic studies enable to reconstruct the geological timescales of many marine formations. However, these investigations are still lacking a precise astronomical tuning in lacustrine environments, particularly in the Middle Jurassic, due to the paucity of biological traces and the lack of data. In this study, detailed spectral analyses of natural gamma ray (GR) logging data were conducted on the lacustrine Sha-1 member from two wells in the Sichuan Basin, southwestern China. Core data samples were calibrated to test the lithological changes for proceeding with cyclostratigraphic analysis with more confidence. The spectral analysis and evolutionary spectral analysis of the GR logs reveal that the wavelength ratios of the stratigraphic cycles are ∼20:5:2:1, being consistent with the period ratios of astronomical cycles (long eccentricity, short eccentricity, obliquity, and precession). Correlation coefficient (COCO) analyses were applied to quantitatively measure the fitting of the witnessed sedimentary cycles to astronomical periods and provide a possible sedimentation rate range. The results show that astronomical time scale of the studied interval comprises 58.4–60.6 m cycles, representing the 405 kyr eccentricity cycles, and 14.9–16.6 m cycles, representing the ∼100 kyr eccentricity cycles. This study reveals a ∼2.43 Myr duration for the Sha-1 member. Sedimentary noise modeling reveals that long-term million-year period (1.2 Myr) astronomical forcing may have been a significant driver of lake-level changes in the Sichuan Basin. Moreover, high-frequency (405 kyr scale) lake-level variations associated with the mid-term base-level cycles (4th-order sequences) were linked to climato-eustatic changes. This study suggests comparison between parameters of cyclostratigraphic records and sequence stratigraphic base-level cycles in lacustrine sediments. The stratigraphic surfaces of mid-term base-level cycles correspond to minima ∼405 kyr-long eccentricity cycle curve and high values of DYNOT (dynamic noise after orbital tuning). Integrating cyclostratigraphy with the base-level cycles is, therefore, a vital approach for defining the short-term oscillations of lake-level, and proved to be a useful tool for characterizing thin-bedded lacustrine reservoirs.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 452-475"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869731","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}
One of the global characteristic features of the Eocene is the extensive development of carbonate platforms in various regions of Tethys. Paleogene sequences of the Shillong Plateau from west to east are exposed in the steep Garo, Khasi and Jaintia hills. In the Khasi and Jaintia hills, Paleogene successions are represented by alternating carbonates and siliciclastics and provide datable micropaleontological fossils, whereas in the Garo Hills, which is in the south-western part of the Shillong Plateau, the Paleogene succession is mainly represented by siliciclastics and fewer carbonates. As the carbonates in this area are mostly marly, the recovery of carbonate microfossils is difficult. Accurate age assignment is important to correlate the sedimentary successions of the Khasi, Jaintia and Garo hills, which are mostly time transgressive and different lithologies were deposited at the same time. A detailed palynological investigation of 65 samples from the 25-m-thick sedimentary succession of the Siju Formation, Western Garo Hills, has yielded well-preserved and diverse organic-walled dinoflagellate cysts and calcareous nannofossils. Dinoflagellate cysts (Heteraulacacysta porosa, H. leptalea) and nannofossils (Discoaster barbadiensis, D. saipanensis, Reticulofenestra bisecta, R. erbae, and R. reticulata) indicate a middle Eocene age (Bartonian) for the studied section. The synthesis of nannofossils and dinocysts with records from India and Australia reveals a major late Bartonian transgression in the Indo-Pacific known as the ‘Kirthar transgression’.
始新世的全球特征之一是特提斯各地区碳酸盐台地的广泛发育。西隆高原的古近系层序自西向东暴露在陡峭的加罗山、卡西山和耆那亚山中。在卡西和耆那亚山，古近系演替以碳酸盐和硅塑料交替为代表，并提供了可测定的微古生物化石，而在西隆高原西南部的加罗山，古近系演替以硅塑料为主，碳酸盐较少。由于该区碳酸盐岩多为泥灰岩，碳酸盐微化石的恢复难度较大。卡西山、耆那亚山和加罗山多为时间海侵，不同岩性同时沉积，准确的年龄划分对于确定其沉积序列具有重要意义。对西加罗山（Western Garo Hills）四聚组（Siju组）25米厚沉积序列中的65个样品进行了详细的孢粉学研究，发现了保存完好且种类繁多的有机壁鞭毛藻囊和钙质纳米化石。鞭毛藻囊（Heteraulacacysta porosa， H. leptalea）和纳米化石（disaster barbadiensis， D. saipanensis, Reticulofenestra bisecta， R. erbae和R. reticulata）表明研究剖面的始新世中期（巴尔顿期）。通过对印度和澳大利亚的纳米化石和恐龙囊的综合研究，揭示了印太地区巴尔顿晚期的一次主要海侵，即“基尔塔尔海侵”。
{"title":"Dinoflagellate cyst and nannofossil imprints in the middle Eocene Kirthar transgressive strata from the western Garo Hills, South Shillong Plateau, India","authors":"Ashish Kumar Mishra , Prem Raj Uddandam , Stuti Saxena , Abha Singh","doi":"10.1016/j.jop.2025.01.005","DOIUrl":"10.1016/j.jop.2025.01.005","url":null,"abstract":"<div><div>One of the global characteristic features of the Eocene is the extensive development of carbonate platforms in various regions of Tethys. Paleogene sequences of the Shillong Plateau from west to east are exposed in the steep Garo, Khasi and Jaintia hills. In the Khasi and Jaintia hills, Paleogene successions are represented by alternating carbonates and siliciclastics and provide datable micropaleontological fossils, whereas in the Garo Hills, which is in the south-western part of the Shillong Plateau, the Paleogene succession is mainly represented by siliciclastics and fewer carbonates. As the carbonates in this area are mostly marly, the recovery of carbonate microfossils is difficult. Accurate age assignment is important to correlate the sedimentary successions of the Khasi, Jaintia and Garo hills, which are mostly time transgressive and different lithologies were deposited at the same time. A detailed palynological investigation of 65 samples from the 25-m-thick sedimentary succession of the Siju Formation, Western Garo Hills, has yielded well-preserved and diverse organic-walled dinoflagellate cysts and calcareous nannofossils. Dinoflagellate cysts (<em>Heteraulacacysta porosa, H. leptalea</em>) and nannofossils (<em>Discoaster barbadiensis</em>, <em>D. saipanensis</em>, <em>Reticulofenestra bisecta</em>, <em>R. erbae</em>, and <em>R. reticulata</em>) indicate a middle Eocene age (Bartonian) for the studied section. The synthesis of nannofossils and dinocysts with records from India and Australia reveals a major late Bartonian transgression in the Indo-Pacific known as the ‘Kirthar transgression’.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 559-578"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869265","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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