• Revisiting the preservation of Chuaria fossils from the Lantian biota
    The Lantian biota, discovered from the Ediacaran basinal-facies deposition of the Lantian Formation near Lantian Town of the Anhui Province, South China, yields an assemblage representing one of the oldest known complex macrofossils. These fossils are preserved on the bedding surface of black shales in the middle part of the Lantian Formation, and their age was estimated at approximately 600 Ma.
      The Lantian biota, discovered from the Ediacaran basinal-facies deposition of the Lantian Formation near Lantian Town of the Anhui Province, South China, yields an assemblage representing one of the oldest known complex macrofossils. These fossils are preserved on the bedding surface of black shales in the middle part of the Lantian Formation, and their age was estimated at approximately 600 Ma.
      The Chuaria fossils usually with spheroidal or disk-like shapes, are the most common macrofossils in the Lantian biota. Although great majority of the Lantian Chuaria fossils are preserved as carbonaceous compressions, Chuaria has been reported to be commonly preserved as pyritization enveloped by aluminosilicate minerals in the upper Member II of the Lantian Formation. The outer minerals that envelope the pyrite layer have been assigned to quartz or aluminosilicate clay minerals. However, their exact mineral compositions as well as whether these minerals have contributed to the exceptional preservation of Ediacaran Lantian Chuaria remain unclear.
      Dr. WANG Wei and her research group from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) employed light microscopy, field emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), and Raman spectroscopy techniques to revisit the preservation of pyritized Chuaria from the Lantian biota.
      "Our taphonomic experiments show Chuaria fossil pyritization occurs at early fossilization process and has contributed to the soft-tissue preservation." Wang says. "The pyritization process is probably divided into at least two stages, which are characterized by distinct pyrite crystal morphologies."
      The pyritized Chuaria fossils are enveloped by platy minerals that are a complex mixture of quartz and magnesium-rich aluminosilicates. Integrated mineral and structural pattern analyses show that these quartz and clay minerals are both secondary overgrowth on Chuaria internal mold, which probably formed as a diagenetic product concurrent with carbonate dissolution in the Lantian black shales. Their formation is probably regulated by local micro-environment near the Chuaria bodies. These enveloped minerals may facilitate preservation and identification of Chuaria fossils, but they are probably not involved in the initial fossilization process as the early diagenetic pyritization has done.
      This research was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of the Chinese Academy of Sciences, and the Science and Technology Research Project for the Research Institute of Petroleum Exploration and Development, CNPC.
      Reference: Wang Wei*, Guan Chengguo, Zhao Xianye, Fang Yan, Zhou Chuanming, Yuan Xunlai (2022) Taphonomic study of Chuaria fossils from the Ediacaran Lantian biota of South China. Precambrian Research, 369: 106529. https://doi.org/10.1016/j.precamres.2021.106529.
      Fig. 1 Images of the Chuaria fossils
       
      Fig. 2 Elemental mapping and Raman spectroscopic investigations on platy minerals
      Fig. 3 A simplified cartoon showing Chuaria fossilization process
       
      Contact:  
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn 
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences 
      Nanjing, Jiangsu 210008, China 
    2022-01-07
  • Determination of Age and Plant Fossils Study to the Devonian Ancient Petroleum Reservoir of North Xinjiang
    Devonian witnessed the first forest on the Earth and the earliest coal formed by land plants. The Middle to Upper Devonian of West Junggar, northern Xinjiang, China yields abundant plant fossils, and finds hydrocarbon source rocks and ancient petroleum reservoirs (APR). The petroleum reservoirs in geological history were destroyed by tectonic movements to form APR. The important mark of APR is solid bitumen.
      Devonian witnessed the first forest on the Earth and the earliest coal formed by land plants. The Middle to Upper Devonian of West Junggar, northern Xinjiang, China yields abundant plant fossils, and finds hydrocarbon source rocks and ancient petroleum reservoirs (APR). The petroleum reservoirs in geological history were destroyed by tectonic movements to form APR. The important mark of APR is solid bitumen.
      Although, the age, formation and destruction of APR have been studied before, no detailed study has been conducted on the plant fossils in APR, and the stratigraphical sequence of APR in the field is different from previous studies. Therefore, it is necessary to conduct in depth study on age, stratigraphical sequence and plant fossils of APR of North Xinjiang.
      Recently, the Devonian Investigation Group (DIG) of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), led by Prof. XU Honghe and Prof. WANG Yi, conducted study on age, stratigraphical sequence and plant fossils of APR of North Xinjiang. The related research results were published in Journal of Stratigraphy and the international journal Plants.
      Based on lithostratigraphical and palaeobotanical study to the Devonian APR, the study demonstrates that the APR belongs to the Upper Member of the Hujiersite Formation with the age of late Middle Devonian (Givetian). The core layer of APR is 2 m thick, and the lithology is dominated by sandstone and mudstone.
      The research also studied the genus of Barsassia in APR. Since the establishment of Barsassia in 1933, there has been a lack of systematic study for a long time, resulting in unclear and confusing generic and specific diagnoses. Here, we systematically study the Devonian lycopsid Barsassia, based on the new materials in APR. Barsassia ornata is determined as the type species of the genus, and a neotype is designated for that name. Barsassia ornata is a herbaceous lycopsid consisting of easily recognized and characteristic step-like stem and tight, pseudowhorls, and imbricate fan- or rectangular-shaped leaves, and can be used in dating and correlating the Middle Devonian terrestrial strata in Siberia, Kazakhstan and Xinjiang.
      References:
      1. Liu, B. C; Zong, R. W; Wang, Y.; Xu, H. H*. 2021. On the age of Devonian ancient petroleum reservoir in West Junggar, northern Xinjiang, China. Journal of Stratigraphy, 45(2): 196-203. https://doi.org/10.19839/j.cnki.dcxzz.2021.0018.
      2. Liu, B. C; Wang, K.; Zong, R. W; Wang, Y.; Xu, H. H*. 2021. Morphology and Nomenclature of Barsassia (Lycopsida) from the Middle Devonian of West Junggar, Xinjiang, China. Plants, 10, 2631. https://doi.org/10.3390/plants10122631.
       
      Fig. 1:The stratigraphical sequence, outcrop and plant fossils in APR.
       
      Fig. 2: Barsassia ornata from APR, with easily recognized and characteristic step-like stem and rectangular-shaped leaves
       
      Contact:
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2022-01-07
  • The slope facies model was proposed for the carbonate mass-tranport deposits
    Systematic study of morphologies, textures and depositional structures in mass-transport deposits (MTDs), as well as associated sedimentary lithofacies, can also help to reveal aspects of tectonic evolution and sedimentary history of basins.
      Subaqueous mass-transport processes, including gravity-induced slides, slumps and debris flows, are one of the mechanisms for transport of sediment into the deep sea. They are of great significance because they shape the sea floor, record climatic and tectonic signals, represent potential catastrophic hazards for human activities and serve as hydrocarbon reservoirs. Systematic study of morphologies, textures and depositional structures in mass-transport deposits (MTDs), as well as associated sedimentary lithofacies, can also help to reveal aspects of tectonic evolution and sedimentary history of basins.
      However, internal structures and depositional processes of carbonate MTDs are relatively poorly understood relative to siliciclastic facies due to their comparative paucity in the rock record. Moreover, it is also challenging to decipher the evolution and internal features of MTDs using remotely-sensed data and drill cores of modern deposits. Accordingly, outcrop-scale study on carbonate MTDs is one important work of sedimentologists.
      During the last few years, Dr. LI Wenjie and Prof. CHEN Jitao from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and American cooperators worked in the Wuhai area, Inner Mongolia for several times. Multi-bedded carbonate MTDs from mid and late Darriwilian to early Sandbian are studied from the aspects of sedimentology and stratigraphy. The study is published in the international academic journal Sedimentology.
      Researchers measured and described the Kelimoli and Wulalike formations of several sections at centimetre scale. The MTDs layers were described in detail. Hundreds of proxies of paleoslope orientation indicators have been measured. Line drawings were made in the field and laboratory to illustrate the soft-sediment deformation structures (SSDS). According to the data and field observation, they concluded the deformational succession of carbonate slump structures, and several unique sedimentary models of carbonate mass flow. Tectonic events related to passive to foreland basin transitions, and associated platform foundering and steepening of the slope were proposed to be the trigger mechanism of the deposition of these MTDs.
      Their findings improved the understanding of transport mechanisms of carbonate MTDs and provided a template for predicting deformational trends of other ancient carbonate slope mass movements. Their stratigraphic and facies model may be applicable to the tectonic history of sedimentary basin analysis and unconventional hydrocarbon resource (such as shale gas) exploration of the western margin of North China.
      This research was supported by the Strategic Priority Research Program (B) of Chinese Academy of Sciences and National Science Foundation of U.S.
      Reference: Li, W. J., Chen, J. T.*, Hakim, A. J., Myrow, P. M., 2021. Middle Ordovician mass-transport deposits from western Inner Mongolia, China: Mechanisms and implications for basin evolution. Sedimentology. https://doi.org/10.1111/sed.12949.
       
       
      Fig. 1 Imbricated beds and folds of the Kelimoli Formation at the Xilaifeng section
      Fig. 2 Breccia-filled channels of the Wulalike Formation at the Yixiantian section
      Fig. 3 Facies model of coarse-grained calciclastic submarine channels formed in steep siliciclastic slope settings.
      Contact:  
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn 
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences 
      Nanjing, Jiangsu 210008, China 
    2021-12-09
  • New development on Mesozoic megaspores in the Tarim Basin, China
    The existing researches are very limited and lack systematic studies, mainly being short material descriptions and reports.
      Megaspore plays an important role in the study of paleovegetation and paleocatlimatic reconstruction and stratigraphy due to its properties of preserving in situ due and clear affinity to the mother plants. However, fossil megaspores have not been fully studied due to their low productivity, which is even later started and poorer developed in China has been compared with international studies. The existing researches are very limited and lack systematic studies, mainly being short material descriptions and reports.
      The Tarim Basin is one of the most important petroliferous basins in China. The Mesozoic strata are important hydrocarbon source rocks of the basin. A researcher group headed by Professor LI Jianguo from Nanjing Institute of Geology and Palaeotology, Chinese Academy of Sciences (NIGPAS), has set out a work on the megaspores of the Mesozoic in the basin during the last decade. They studied several hundreds of samples collected from 34 outcrop or underground drilling well sections in the Tarim Basin. A total of 108 species of 27 genera have been identified, redescribed and illustrated. Eight palynological assemblage zones spanning the Early Triassic to Early Cretaceous are recognized based on the distribution of representative taxa and compositional changes in the megaspore assemblages. Stratigraphic and palaeoenvironmental values of selected genera and species are also discussed.
      This work has currently been officially published by Science Press China as "Mesozoic Megaspores and Palynomorphs from Tarim Basin, Northwest China" (Palaeontologica Sinica, Volume 202). This is the first Chinese and English language controlled research monograph on fossil macrospores in China. It will strongly promote the study of Mesozoic fossil megaspores, the stratigraphic division and correlation, and petroleum exploration in the Tarim Basin.
      Cover of "Mesozoic Megaspores and Palynomorphs from Tarim Basin, Northwest China"
      Fossil plates on the inside of this monograph
       
      Contact:  
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn 
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences 
      Nanjing, Jiangsu 210008, China 
    2021-11-25
  • Felsic Volcanism in South China Drove the End-Permian Mass Extinction
    About 252 million years ago, more than 81 percent of animal life in the oceans and 89 percent of animal life on land went extinct. This event, called the "end-Permian mass extinction" (EPME), represents the greatest catastrophe in the history of life on Earth. The proximate driver of the event has long been a mystery.
      About 252 million years ago, more than 81 percent of animal life in the oceans and 89 percent of animal life on land went extinct. This event, called the "end-Permian mass extinction" (EPME), represents the greatest catastrophe in the history of life on Earth. The proximate driver of the event has long been a mystery.
      However, a new study led by scientists from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) and Nanjing University has now revealed that Felsic volcanism in South China drove the EPME.
      The study was published in Science Advances on Nov. 17.
      Previous studies suggested that volcano eruptions in Siberia, an event called the "Siberian Traps large igneous province (STLIP)," was the single major driver of the mass extinction event. The support for this argument comes from the observation that STLIP was large enough to perturb the global environment.
      The team, however, noted that temporal links between the mass extinction and volcanism were largely based on sedimentary records from South China, while the Siberian region does not contain direct evidence of biological extinction. The scientists also noted that more than one-third of the erupted volcanic rocks and the entire STLIP intrusive magmatism postdated the end-Permian mass extinction horizon.
      Therefore, the team wanted to determine if volcanic eruptions from other regions could help explain the EPME. In this study, the team focused on terrestrial ecosystems, which were decimated during the EPME.
      Typically, scientists identify ancient volcanic eruptions by looking at the abundance of volcanic rocks preserved on Earth's present-day surface, and anomalies of elemental mercury in ancient sedimentary rocks. But volcanic rocks can be weathered or covered and disappear from the Earth's surface. Furthermore, enrichment of elemental mercury in sedimentary rocks does not always indicate the presence of volcanic eruptions.
      To overcome this, the team pioneered a new and more efficient approach. By studying variations in elemental copper and its isotopes recorded in sedimentary rocks, the team was able to infer large-scale volcano eruptions near the studied outcrops. These sediments, collected in modern-day South China, recorded the entire EPME.
      The resulting extreme elemental copper enrichment and the associated anomalously light isotopic compositions in the EPME interval in South China gave the answers the researchers were looking for. They were able to show that large-scale eruptions near the South China Block were synchronous with the EPME.
      The new study has strengthened the case that the STLIP may not have been the sole trigger for the extinction.
      "This finding provides critical new insights into mechanisms that led to the extinction of animal life both in the ocean and on the land. We suggest that felsic volcanism in South China was a key contributor to the environmental deterioration that led to the end-Permian mass extinction," said Prof. ZHANG Hua from NIGPAS, the first author of the study.
      The discovery calls attention to the possible effects of modern climate change. The new study estimated that volcanic SO2 injections would have produced several degrees of rapid cooling before or coincident with the more protracted global warming caused by CO2 injections. Such swings in end-Permian climate from volcanic carbon and sulfur outgassing could create deadly environments for ecosystems.
      "One of the most interesting and worrying things about the end-Permian extinction is how similar those events are to what is happening today," said corresponding author Prof. SHEN Shuzhong from Nanjing University. "Similar to what happened during the end-Permian period, the modern Earth is facing rapid climate warming due to anthropogenic CO2 emissions."
       
      Fig. 1 Photographs and photomicrographs of Cu-rich sulfide and charcoal from the terrestrial Permian-Triassic transition. (Image by NIGPAS)
       
      Fig. 2 Schematic showing the formation process of copper-rich deposits within the EPME interval in South China. (Image by NIGPAS)
       
      Contact:  
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn 
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences 
      Nanjing, Jiangsu 210008, China 
    2021-11-18
  • The first study of organic-walled microfossils from Middle Ordovician nodular cherts in China
    The acritarch fossil assemblage in chert can be compared with other regional assemblages in the world at the same time, and can be also used for outcrop and drilling core biostratigraphic correlation, which has important industrial significance.
      During the Ordovician period, siliceous rocks were widely deposited in many parts of the world, including Kazakhstan and eastern Australia. Although the micropaleontology of Ordovician deep-sea cherts is relatively well documented, microfossil assemblages in Ordovician shallow-marine cherts are less well-known.
      Recently, associate researchers MENG Fanwei and YAN Kui, and master student YUAN Xuejun, from Nanjing Institute of Geology and paleontology, Chinese Academy of Sciences (NIGPAS), in cooperation with senior engineers ZHANG Zhili and LI Huili, from Sinopec petroleum exploration and Development Research Institute, studied the drilled carbonate rock core of Yijianfang Formation in the Middle Ordovician of Well YJ-1 in the north of Tarim Basin, China, and found a large number of chert nodules in the carbonate rock. The related research results were published in the international SCI journal Carbonates and Evaporites.
      Abundant fossil algal assemblages were found in the sections of chert nodules. It includes 11 genera of planktonic algae fossils (acritarch) and filamentous cyanobacteria, revealing the biological assemblage of Middle Ordovician chert facies. The Yijianfang Formation fossil assemblage indicates a deep offshore depositional environment. Sedimentological evidence also suggests that the limestone that hosts the chert interval was deposited in a low- to moderate-energy, restricted, inner carbonate platform. Cherts formed by silicification during late diagenesis.
      Previously, Chinese Ordovician micro planktonic algae fossils (acritarch) basically came from shale immersion. This study is the first study of Ordovician chert facies fossils in China, which enriches the understanding of Ordovician biosphere. The acritarch fossil assemblage in chert can be compared with other regional assemblages in the world at the same time, and can be also used for outcrop and drilling core biostratigraphic correlation, which has important industrial significance.
      This research is supported by the National Natural Science Foundation of China, the China-Israel cooperation Project of the National Natural Science Foundation of China, and the original innovation project of "from 0 to 1" of the basic frontier science research program of the Chinese Academy of Sciences.
      Reference: Zhang, Zl., Meng, Fw., Zheng, Qf. et al. Microfossils from nodular cherts in the Middle Ordovician Yijianfang Formation carbonates (Well YJ1X), Tarim Basin, China. Carbonates Evaporites 36, 38 (2021). https://doi.org/10.1007/s13146-021-00689-7.
      Figure 1. Fossil algae in nodule cherts of Yijianfang Formation in Middle Ordovician of Well YJ-1 in northern Tarim Basin, China
      Contact:  
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn 
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences 
      Nanjing, Jiangsu 210008, China 
    2021-11-12
  • Study Reveals Effects of End-Permian Deforestation on Early Evolution of Beetles
    The end-Permian mass extinction (EPME) led to a severe terrestrial ecosystem collapse. Insects have diversified over the past approximately 400 million years and account for roughly half of the biodiversity on Earth today. However, the ecological response of insects to the EPME remains poorly understood.
      The end-Permian mass extinction (EPME) led to a severe terrestrial ecosystem collapse. Insects have diversified over the past approximately 400 million years and account for roughly half of the biodiversity on Earth today. However, the ecological response of insects to the EPME remains poorly understood.
      Beetles (Coleoptera) are the most speciose group of extant insects, with a stratigraphic range dating back to at least the lowest Permian. They have a rich fossil record since the Permian and display a wide array of lifestyles. Their fossil record thus offers a unique and complementary perspective for studying the ecological response of insects to the EPME.
      Recently, postgraduate researcher ZHAO Xianye, Prof. WANG Bo from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS), and other researchers from China, Russia, the USA and UK analyzed the evolutionary history of early beetles.
      Their findings suggest that xylophagous (feeding on or in wood) beetles probably played a key and underappreciated role in the Permian carbon cycle and early archaic beetles experienced severe ecological consequences of end-Permian deforestation.
      These results further provide new insights into the ecological role of insects in deep-time terrestrial ecosystems as well as the ecological response of insects to deforestation and global warming.
      The study was published in the international academic journal eLife on Nov. 8.
      The research team compiled an updated database of beetles from the Early Permian to Middle Triassic based on the taxonomic revision of fossils. They analyzed the evolution of taxonomic diversity, morphological disparity and palaeoecological shifts of beetles from the Early Permian to Middle Triassic through phylogenetic and palaeoecological reconstructions and morphospace analyses of fossil material.
      The suite of analyses show that Permian xylophagous beetles suffered a severe extinction during the EPME largely due to the collapse of forest ecosystems, thus resulting in an Early Triassic gap of xylophagous beetles. New xylophagous beetles appeared widely in the early Middle Triassic, which is consistent with the restoration of forest ecosystems.
      Permian beetles probably played an important ecological role in forest ecosystems because most Permian beetles were probably xylophagous insects that consumed living and dead woody stems. Furthermore, xylophagous beetles may have been responsible for the decrease of oxygen concentrations in the Permian. The research highlights the ecological significance of insects in deep-time terrestrial ecosystems.
      Extant insects are suffering from dramatic declines in abundance and diversity largely due to anthropogenic deforestation and global warming. However, xylophagous insects have been largely neglected in studies of the current extinction crisis. The current study may help researchers better understand future changes in insect diversity and abundance and the consequences of such developments as the world faces global environmental change.
      This research was supported by the Chinese Academy of Sciences and the National Natural Science Foundation of China.
       
      Fig. 1 Examples of Permian beetles and reconstructions. (Image by NIGPAS)
       
      Fig. 2 Phylogeny of early beetles (A) and genus percentages of xylophagous groups (B) (Image by NIGPAS)
       
      Contact:  
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn 
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences 
      Nanjing, Jiangsu 210008, China 
    2021-11-10
  • High-resolution Ediacaran timescale revealed by high-precision geochronology
    The Ediacaran Period (635–539 million years ago, Ma) is a pivotal period in Earth history, archiving the rise of complex macroscopic life. This evolutionary milestone occurred in the aftermath of extreme climate perturbations, the Cryogenian snowball Earth events, and amid dramatic changes in the global carbon cycle and ocean redox conditions.
      The Ediacaran Period (635–539 million years ago, Ma) is a pivotal period in Earth history, archiving the rise of complex macroscopic life. This evolutionary milestone occurred in the aftermath of extreme climate perturbations, the Cryogenian snowball Earth events, and amid dramatic changes in the global carbon cycle and ocean redox conditions.
      These perturbations, including the Shuram event which is the largest magnitude negative carbon isotope excursion in Earth history, have been documented worldwide, and are commonly employed to establish regional to global stratigraphic correlations. However, there is a lack of a chronostratigraphic framework at sufficient resolution for testing hypotheses related to the tempo, magnitude/duration of the events (especially the Shuram), their global expression, or their co-relationship with biospheric evolutionary innovations.
      Published in Science Advances, a study by an international research team led by Prof. Zhu Maoyan (Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences) presents new radio-isotopic dates from Ediacaran successions in South China and White Sea area. The new dates provide age constraints on both the Ediacaran fossil assemblages and the carbonate carbon isotope perturbations.
      The upper Ediacaran is characterized by the typical Ediacara-type fossils. Three assemblages of the fossils have been recognized: the Avalon, White Sea, and Nama. The age ranges of the Avalon and Nama assemblages have been constrained at 575–560 Ma and 550–539 Ma, respectively. New dates from the study indicate that the White Sea assemblage spans a time interval started earlier than 557 Ma and ended later than 553 Ma. The age constraints on these three fossil assemblages can facilitate our understanding of the evolution in the late Ediacaran. New dates from South China also provide age constraints on the Doushantuo acanthomorphic acritarchs, Weng’an biota, Wenghui biota, Miaohe biota, and Ediacara-type fossils in the Dengying Formation.
      The terminal timing of the Shuram event was constrained at 551 Ma. However, the lack of high precision radio-isotopic dates and the complexity of local stratigraphy have given rise to much debate about the number of negative carbon isotope excursions in the late Ediacaran and the age of the Shuram event. The new dates indicate that there are two negative carbon isotope excursions in 575-550 Ma. The older and long-lasting one is the Shuram event, and the younger and short-lived one occurred at 550 Ma. The authors also compile a global Ediacaran geochronology database and suggest that the Shuran event occurred between 575 Ma and 565 Ma with an uncertainty on the order of a few million years. Older than the Shuram event, another short-lived negative carbon isotope excursion, which is locally called WANCE in South China, is dated at ~587 Ma.
      The presented Ediacaran age model for the carbon cycle perturbations and fossil records provides the necessary chronometric context to test causal relationships, if any, between them. At the current resolution, these transitions in the fossil record coincide with the carbonate carbon isotope excursions, suggestive of a potential causal relationship between environmental perturbations recorded in the carbon cycle and biological turnovers.
      The study was supported by grants from the Chinese Academy of Sciences, the National Natural Science Foundation of China, the Natural Environment Research Council of the UK, the United States National Science Foundation, and the Russian Science Foundation.
      Reference: Yang, C.*, Rooney, A.D.*, Condon, D.J., Li, X.-H., Grazhdankin, D. V, Bowyer, F.T., Hu, C., Macdonald, F.A., and Zhu, M.*, 2021, The tempo of Ediacaran evolution. Science Advances, 7, eabi9643. https://www.science.org/doi/10.1126/sciadv.abi9643.
      Fig. 1 Integrated radio-isotopic dates, fossil ranges, and carbon isotopic profile of the Ediacaran Period
       
      Contact:  
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn 
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences 
      Nanjing, Jiangsu 210008, China 
    2021-11-04
  • The first cladistic analysis to the order Lituitida
    As the index fossils in Middle to Late Ordovician, the classification and phylogeny of lituitids have been long debated.
      There have been several cladistic analyses of the phylogeny of different groups of 'nautiloid' cephalopods, including classification at lower taxonomic levels, generic affinities and their evolutionary path at higher taxonomic levels. However, a systematic and comprehensive analysis is still pending, and many taxa have never been investigated.
      Lituitid cephalopods are distinguished from other Ordovician cephalopods by their specific conch shape and ornaments. Most of them have a coiled or cyrtoconic part at the early growth stage, and then develop the uncoiled or fully straight conch at the late stage.
      As the index fossils in Middle to Late Ordovician, the classification and phylogeny of lituitids have been long debated. Recently, Dr. FANG Xiang and colleagues from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and researchers from Universitat Zürich, University of Helsinki, Charles University in Prague and Mahasarakham University, conducted phylogenic analysis on Lituitida (Cepahlopoda), based on the large amount materials from South China. This work has been published in Journal of Systematic Palaeontology.
      The first cladistic analysis of the order Lituitida based on published was presented, as well as some new, material. Three clades are recovered within the ingroup of lituitids, Sinoceras, Ancistroceras and Lituites; the former group correspond to the family Sinoceratidae, and the latter two to the Lituitidae.
      "The topology shows that the Sinoceratidae represents the basal branch, while the Lituitidae represents a monophyletic, derived clade", Dr. FANG Xiang says, "Furthermore, we describe new material of four species (three of which are newly defined) in four genera of the order Lituitida from the well-exposed, Middle to Upper Ordovician of Hubei (South China). Tyrioceras longicameratum from South China is the first reported occurrence of Tyrioceras in China, which has significant palaeogeographical implications."
      This research is supported by Chinese Academy of Sciences Strategic Priority Research Program and National Natural Science Foundation of China. 
      Reference: Fang, X.*, Pohle, A., Kroger, B., Aubrechtová, M., Burrett, C., Zhang, Y.B., Zhang, Y.D., 2021. Phylogeny of Middle–Late Ordovician lituitid cephalopods based on cladistic analysis. Journal of Systematic Palaeontology, 19(9): 633–350. https://doi.org/10.1080/14772019.2021.1944354.
      Cladistic analysis on Lituitida (Cephalopoda) 
      Rhynchorthoceras yizanense sp. nov. from Datianba Formation, Sangzhi, Hunan Province
      Contact:  
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn 
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences 
      Nanjing, Jiangsu 210008, China 
    2021-10-27
  • New high-precision chronostratigraphy of Permian in the North China block
    The study provides a fundamental revisions to the traditional Permian terrestrial depositional history and chronostratigraphy of the North China block, and provide a new timeline and important insights for the history of continental collision, floral turnovers, and paleoclimate change as recorded in the North China block.
      The study provides a fundamental revisions to the traditional Permian terrestrial depositional history and chronostratigraphy of the North China block, and provide a new timeline and important insights for the history of continental collision, floral turnovers, and paleoclimate change as recorded in the North China block.
      The North China block occupied northerly tropical to subtropical paleolatitudes, marginal to the Paleo-Asian Ocean (PAO), during the critical Cisuralian (298.9-273.0 Ma) transitions from an icehouse to a greenhouse world. The late Carboniferous to Permian marine and marginal-marine to terrestrial sequences in North China preserve highly diverse and abundant plant fossils in addition to their significant economic hydrocarbon resources. These characteristics provide a unique opportunity to investigate the interactions among terrestrial biotic evolution, regional tectonics, and global climate change during a critical period of geologic history.
      However, poor constraints on age and correlation have hampered a deep understanding of those events in the North China block. In the absence of diagnostic marine fossils from key intervals, stratigraphic correlation within and beyond North China has relied on uncalibrated palynostratigraphy and phytostratigraphy and magnetostratigraphy. Detrital zircon geochronology by U-Pb in situ analyses from Permian volcaniclastic sandstones generally lacked the necessary precision or stratigraphic range to place reliable constraints on depositional ages.
      Recently, the Late Paleozoic research group from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), Nanjing University and other researchers from China, USA and Canada, report high-precision U-Pb zircon geochronology by the chemical abrasion–isotope dilution–thermal ionization mass spectrometry (CA-ID-TIMS) method focused on bentonitic tuffs from the Permian succession in North China. New high-precision U-Pb geochronology necessitates major revisions to the temporal framework for the Permian terrestrial system in North China. The research results were recently published in the international academic journal Geology.
      The Upper Shihhotse Formation spans the latest Asselian to the early Kungurian, as opposed to its previous Wordian to Wuchiapingian age assignments. A major depositional gap during the late Cisuralian to Guadalupian in the northern North China block may have been caused by convergent tectonics associated with the closure and/or subduction of the PAO.
      The great loss of highly diverse and abundant Cathaysian floras and the widespread invasion of the Angaran floras under arid climate conditions in the North China block happened during the late Cisuralian to Guadalupian, but its exact timing is uncertain due to the long hiatus. The Cisuralian global aridification may have been associated with extensive LIP volcanism and the rise of atmospheric CO2 in the waning stages of the LPIA.
      The research was supported by the Strategic Priority Research Programs (B) of the Chinese Academy of Sciences.
      Reference: Q. Wu, J. Ramezani, H. Zhang*, J. Wang, F. Zeng, Y. Zhang, F. Liu, J. Chen, Y. Cai, Z. Hou, C. Liu, W. Yang, C. M. Henderson, S. Shen*,2021, High-precision U-Pb age constraints on the Permian floral turnovers, paleoclimate change and tectonics of North China. Geology 49, 677–681. https://doi.org/10.1130/G48051.1
      Figure 1. Compilation of Permian global events in parallel with Earth system changes in the North China block.
      Contact:  
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn 
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences 
      Nanjing, Jiangsu 210008, China 
    2021-10-22