• A new species of primitive stromatoporoid from the Ordovician of East Asia

      Paleozoic stromatoporoids have long been considered to have emerged during the late Middle Ordovician. Five of seven families in the Order Labechiida appeared nearly contemporaneously during the Darriwilian throughout the low-paleolatitude regions of Laurentia, Siberia and Gondwana. This rather sudden and almost simultaneous widespread Darriwilian appearance of diverse early stromatoporoids has been explained by two different hypotheses: the conventional view states that the early stromatoporoids arose from one or two basic skeletonized rosenellids such as Cystostroma or Pseudostylodictyon, whereas the alternative hypothesis suggests that stromatoporoids rose from ‘a simple, non-calcifying sponge root stock’ that acquired the ability to secrete a mineralized skeleton during the Darriwilian.
      Recently, Dr. LI Qijian from Nanjing Institute of Geology and Palaeontology and his collaborators from South Korea have reported a new species of the most primitive rosenellid stromatoporoid Cystostroma (C. primordia sp. nov.) from the Hunghuayuan Formation (Lower Ordovician, Floian) of Guizhou Province in the South China Block (Figure 1) and the Duwibong Formation (Middle Ordovician, Darriwilian) of the Taebaeksan Basin in mid-eastern Korea (North China Block) (Figure 2). This species is the first representative of the genus found in both the North and South China blocks. Cystostroma primordia sp. nov. is characterized by the absence of denticles and distinctively smaller cyst plates than any other known species of Cystostroma.
      The presence of this new species in Lower to Middle Ordovician strata of western Gondwana challenges the long-held view of the late Middle Ordovician emergence of Paleozoic stromatoporoids. The simple internal morphological features of this new species and its occurrence in the Lower Ordovician of South China strongly indicate that an Early Ordovician Cystostroma-type precursor from western Gondwana is located near the base of the stromatoporoid stock. This occurrence greatly preceded the late Middle Ordovician (late Darriwilian) stromatoporoid diversification in circum-equatorial regions worldwide.
      Reference: Juwan Jeon, Qijian Li, Jae-Ryong Oh, Suk-Joo Choh, Dong-Jin Lee. 2018. A new species of primitive stromatoporoid Cystostroma from the Ordovician of East Asia. Geosciences Journal, DOI: https://doi.org/10.1007/s12303-018-0063-7
      Photomicrographs of the labechiid stromatoporoid Cystostroma from South China.
      Field photographs of a stromatoporoid-bryozoan skeletal reef in the Duwibong Formation. Scale bars in Figures 2b and c = 1 cm.
    2019-01-24
  • Plant fossils indicate a moderate palaeoelevation in the Kailas basin during the latest Oligocene

      The uplift of Tibetan Plateau had a significant impact on the evolution of regional and global climate during the Cenozoic including the origin and evolution of the Asian monsoon system and the aridification in northwestern China. The Lhasa terrane has been considered a key region for understanding the elevation history of the southern Tibetan Plateau after collision of continental India and Asia in early Paleocene. Stable isotopic studies consistently suggest that the Lhasa terrane had reached its near-present elevation before the Miocene.
      In a recent collaborative study by Dr. Gongle Shi, Professor Shuangxing Guo, and the research group of Professor Kexin Zhang from China University of Geosciences, Wuhan, a plant megafossil assemblage from the Kailas Formation of the Kailas Basin in western part of the southern Lhasa terrane was reported.
      The U-Pb dating and magnetostratigraphic correlation show that the studied section of the Kailas Formation ranges from 25.1 Ma to 21.8 Ma in age, and that the fossil flora occurred at 23.3 Ma (latest Oligocene).
      The uppermost Oligocene Kailas fossil flora is low in diversity and dominated by Populus, Betulaceae and legume. It most likely represents a deciduous, broad-leaf vegetation and suggests a temperate, humid environment with a low to moderate palaeoelevation of 1500–2900 m in the Kailas Basin during the latest Oligocene, based on the co-existing range of the living analogues of the fossil plants. This conflicts with the existence of a continuous, high Gangdese Mountains stretching across the whole southern Lhasa terrane in the late Oligocene. Available evidence appears to suggest strong uplift of the southern Lhasa terrane after the latest Oligocene.
      The research was recently published in “Palaeogeography, Palaeoclimatology, Palaeoecology”. This work is funded by the Foundation of the Geological Survey of China, the National Natural Science Foundation of China, and the Youth Innovation Promotion Association, CAS.
      Reference: Ai K., Shi G.*, Zhang K.*, Ji J., Song B., Shen T., Guo S., 2018. The uppermost Oligocene Kailas flora from southern Tibetan Plateau and its implications for the uplift history of the southern Lhasa terrane. Palaeogeography, Palaeoclimatology, Palaeoecology. DOI: 10.1016/j.palaeo.2018.04.017.https://www.sciencedirect.com/science/article/pii/S0031018217307496
      Populus from the uppermost Oligocene of the Kailas Basin
    2019-01-24
  • Fossil dinoflagellate cysts indicate the Palaeoenvironment of late Palaeogene in Huabei Oilfield

      During late Cretaceous to Palaeogene, there were many terrestrial salty basins in Eastern China. Many of the basins are the main oilfields in Eastern China, and salt rocks in the basins formed good cap rocks for gas and oil. Since 1970s, it has been debated that these basins were terrestrial salt lakes or transgressed by sea.
      The Palaeogene Shahejie Formation in the Shulu Sag of Huabei Oilfield developed a great thickness of sediments of evaporate rocks, among which layers of mudstones also occurred.
      Dr. Cheng Jinhui and Dr. Meng Fanwei of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and Dr. Zhao Yanjun of Chinese Academy of Geological Sciences discovered some well-preserved fossils of dinoflagellate cysts in this formation. Salt rocks and assemblage of fossil dinoflagellate cysts indicate a palaeoenvironment of salt lake. The discovery not only indicates the palaeoenvironment of late Palaeogene, but also is helpful for the evaluation of oil source rocks in this set of salt-bearing strata.
      Reference: Cheng, J., Zhao, Y. & Meng, F. 2018. Paleogene organic-walled dinoflagellate cysts in the Shulu Sag, Hebei Province, China. Carbonates and Evaporites. DOI: https://doi.org/10.1007/s13146-018-0456-8
      Mudstones interweaved with salt in core NY3 in the Shulu Sag.
      Dinoflagellate cysts from Core NY3 in the Shulu Sag. 
    2019-01-24
  • Morphometrics, growth characteristics and phylogenetic implications of Halysites catenularius

      Based on multivariate morphometric analysis, Halysites catenularius is identified from the Rumba Formation (Telychian) and Jaagarahu Formation (Sheinwoodian) of Estonia; H. priscus is confirmed as a junior synonym. Halysites catenularius, H. junior and H. senior are shown to be closely related; H. catenularius is morphologically intermediate.
      Cyclomorphism in H. catenularius, recorded by fluctuations of corallite tabularial area, indicates an average annual growth rate of 6.0 mm, which is typical for halysitids.
      Tubules in H. catenularius, generated from small intramural openings between adjacent corallites, were involved in two types of interstitial increase.
      The intramural openings, three types of lateral increase, temporary agglutinated patches of corallites, and axial increase documented in H. catenularius resemble features in some species of Catenipora.
      These similarities are consistent with the interpretation that Halysites evolved from Catenipora. Evaluation of the possibility that both genera are polyphyletic will require further detailed analysis of additional species.
      Reference: Liang, K., Elias, R.J., Lee, D.-J. 2018. Morphometrics, growth characteristics and phylogenetic implications of Halysites catenularius (Tabulata, Silurian, Estonia). Journal of Paleontology. https://doi.org/10.1017/jpa.2018.73
      Growth cycles detected from fluctuations of corallite tabularial area base on serial peels
      A new offset developed by interstitial increase and formation of new tubules (arrows) in Halysites catenularius
      New offsets developed by lateral increase (arrows) in Halysites catenularius
    2019-01-24
  • Updated integrative timescale for the Lopingian according to conodont succession

      The Lopingian is the uppermost series of the Paleozoic and it is bracketed by two major biological events – the pre-Lopingian crisis and the end-Permian mass extinction (EPME). It also records the most dramatic environmental changes during the Phanerozoic. A high-resolution temporal framework is essential to understand the patterns and causes of the extinctions.
      Lopingian strata of South China have been intensively studied because three GSSPs have been defined by the FADs of conodont species in the region. In addition, as the most important fossil group for Lopingian biostratigraphy, conodonts are selected as the international standard to recognize boundaries and to correlate stratigraphy. Thus, a high-resolution conodont succession for the Lopingian strata from South China is vital to establish an integrative timescale.
      Recently, Dr. Dongxun Yuan from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences updated the integrative timescale, including biostratigraphy, chemostratigraphy, magnetostratigraphy, cyclostratigraphy and geochronology, for the Lopingian (Late Permian) based on results from newly-collected samples from the uppermost Guadalupian to the lowest Triassic at the Shangsi section, South China.
      The entire Lopingian high-resolution conodont succession was for the first time, since the Lopingian Series was adopted as the international standard, recognized at a single section in South China and the succession correlated very well with the Lopingian GSSP sections at Penglaitan and Meishan. The conodont succession was also temporally calibrated by geochronologic ages, identified 405-kyr eccentricity cycles, and a Monte Carlo analysis. The framework provided the possibility that the current high-resolution marine international standard can be correlated with nonmarine strata by means of magnetostratigraphy and cyclostratigraphy.
      The study also adopted the Unitary Associations approach to establish unitary association zones (UAZs) and test these conodont biozones based on seven important Lopingian sections of South China. The main contradictions between UAZs and biozones, especially at the PTB interval, were discussed, and the correspondence between UAZs and biozones of the Shangsi section provided a practical example to understand controls on conodont UAZs. The PTB of the Shangsi section was constrained in view of ammonoids, bivalves, conodonts, U-Pb ages and mass extinction event, and updated ages for the base of the Lopingian and base of the Changhsingian were provided.
      Reference: Yuan D.X.*, Shen S.Z., Henderson C.M., Chen J., Zhang H., Zheng Q.F., Wu H.C., 2019. Integrative timescale for the Lopingian (Late Permian): A review and update from Shangsi, South China. Earth-Science Reviews, 188: 190-209. DOI: https://doi.org/10.1016/j.earscirev.2018.11.002.
      Exposure of the Shangsi section and outcrops showing the PTB interval
       
      Lopingian stratigraphic framework at the Shangsi sect
    2019-01-24
  • First report of tommotiid fossils from the Lower Cambrian, North China

      Tommotiids are a group of Early Cambrian fossils with multiple small organophosphatic sclerites, and are a kind of extraordinary animals occurring during the Cambrian Explosion. Due to lack of well-preserved scleritome fossils, their zoological affinities had been uncertain for a long time. Over the past years, discovery and study of some articulated scleritomes indicate that tommotiids may belong to stem-group brachiopods. Though their soft-part anatomy is hitherto unknown, it has been argued that bivalved brachiopod shells probably evolved from an Eccentrotheca-like stem group ancestor through intermediary forms (e.g. Paterimitra pyramidalis) by the successive stages of sclerite reduction, specialization and tube shortening. Although tommotiids are common and globally distributed in the Lower Cambrian, they were not discovered from North China Platform yet.
      Recently, PhD candidate PAN Bing from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and colleagues from Australia and Sweden reported the first discovery of the tommotiid Paterimitra pyramidalis from the Lower Cambrian Xinji Formation of North China Platform. Paterimitra pyramidalis was previously only found from the Early Cambrian of Australia, and its articulated coniform scleritome specimens from Australia with three morphotype sclerites indicate that it was probably a sessile filter feeder (attaching to hard substrates via a pedicle). Like the Australia material, the disarticulated sclerites of P. pyramidalis from the Xinji Formation include three morphotypes, i.e., S1, S2 and L sclerites. This discovery not only represents the first occurrence of P. pyramidalis outside Australia, but also it is the first report of tommotiids in North China.
      The previous discovery of Paterimitra pyramidalis sclerites in a range of lower Cambrian carbonate depositional facies from south and central Australia (part of the eastern Gondwana in early Cambrian) demonstrates their dispersal ability along epeiric platform. Its occurrence in North China suggests that P. pyramidalis should have a relatively longer planktotrophic larval period to let its larvae cross the oceanic barriers between eastern Australia and southern North China in the early Cambrian. But, the exclusive occurrence in Australia and North China indicates their dispersal ability is limited and hints that these two regions should have had close palaeogeographic proximity in that interval.
      The exact palaeogeographic position of the North China Platform in the early Cambrian has long been controversial. It has been variously placed along the margin of western Gondwana bordering today's north-eastern India, or as an independent continent in either close juxtaposition to the north of Australia, or close to north-eastern margin of Australian East Gondwana, or located thousands of kilometers to the east of Australia in the Palaeo-Pacific Ocean. The co-occurrence of P. pyramidalis and many other shelly fossils in both the North China Platform and Australian East Gondwana supports that these two areas had a close palaeobiogeographic link during the early Cambrian.
      This research was recently published in Gondwana Research, and was supported by grants from the National Natural Science Foundation of China, the Chinese Academy of Sciences and Swedish Research Council.
      Reference: Pan, B., Brock, G.A., Skovsted, C.B., Betts, M.J., Topper, T.P., Li, G.X.*, 2018. Paterimitra pyramidalis Laurie, 1986, the first tommotiid discovered from the early Cambrian of North China. Gondwana Research, 63: 179-185. doi:10.1016/j.gr.2018.05.014
      Paterimitra pyramidalis Laurie, 1986 from the Xinji Formation, Cambrian Epoch 2, North China.
      Palaeogeographic distribution of Paterimitra pyramidalis in Cambrian Epoch 2 (palaeogeographic map modified from Torsvik and Cocks, 2013b; Yang et al., 2015).
    2019-01-24
  • Late Permian foraminifers in the Lhasa Block, Tibet and their geological implications

      The Qinghai-Tibet Plateau which is made up of multiple blocks has a complicated geological history. The different geographical locations of these blocks resulted in different fauna during the geological history because of the presence of pronounced thermal gradients. The Permian faunas and their paleobiogeographic affinities have been proved to be the reliable data to recognize the paleogeographic position for many Tibetan blocks.
      The Upper Permian strata of Lhasa Block have been previously considered as continental strata with fossil plants. Consequently, it was believed that the Lhasa Block had been uplifted into land during the Late Permian. The Lopingian marine strata have been reported in Lhasa Block in recent years, which challenges the traditional viewpoint. However, the taxonomy and palaeobiogeography of these marine faunas remain uncertain.
      Recently, Prof. ZHANG Yichun, researchers at the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences, conducted a research on the foraminifers from the topmost part of the Xiala Formation in the Tsochen area, central Lhasa Block.
      The fauna mainly consist of Colaniella, Reichelina, Sphaerulina, Neodiscus, Langella and Geinitzina, indicating a Changhsingian age. The most typical feature of this fauna is the absence of Palaeofusulina. More importantly, no Palaeofusulina fauna has been reported in the whole Lhasa Block and such is the case for those Gondwanan blocks. But the Palaeofusulina species has been reported in the west of South Qiangtang Block. It suggests that the South Qiangtang Block would have drifted northward to a low latitude region during the Changhsingian, but the Lhasa Block may still locate at a relatively southern position. This indicates that the Bangong-Nujiang Ocean has a considerable width at that time, which is consistent with the view that the Bangong-Nujiang Ocean opened before the Middle-Late Permian.
      On the other hand, the Permian sedimentary sequence and faunas of the Lhasa Block exhibits a great difference to the South Qiangtang Block and Himalaya terrane. Therefore, it is considered that the Lhasa Block was an independent block between the Bangong-Nujiang Ocean and the Neotethys Ocean during the Changhsingian.
      This work was financially supported by Strategic Priority Research Program of Chinese Academy of Sciences and the National Natural Science Foundation of China.
      Reference: Feng Qiao, Hai-Peng Xu, Yi-Chun Zhang*, 2019. Changhsingian (Late Permian) foraminifers from the topmost part of the Xiala Formation in the Tsochen area, central Lhasa Block, Tibet and their geological implications. Palaeoworld, Doi: 10.1016/j.palwor.2018.10.007.
      Fieldwork in Tibet
      Foraminifers from the topmost part of the Xiala Formation (1)
      Foraminifers from the topmost part of the Xiala Formation (2)
      Distribution pattern for the fusulines Palaeofusulina and the forminifera Colaniella during the Changhsingian (Lopingian)
    2019-01-24
  • Plant fossils indicate the pattern of Devonian transgression after the Kwangsian Orogeny in the Cathaysia Block

      The euphyllophyte Pauthecophyton sp. from the Lower Devonian Yangling Psephyte, Chongyi, Jiangxi Province, China The South China Plate, being situated at the periphery of the Gondwana supercontinent in the Paleozoic, was formed by the Neoproterozoic (ca. 850-820 Ma) amalgamation of the Yangtze and Cathaysia blocks, both of which belonged to a unified continental terrane and between which there was an epicontinental sea during the Paleozoic. A major geological event in the South China Plate was recognized by angular unconformities or disconformities between the Devonian and the Lower Paleozoic (early Silurian and pre-Silurian) strata. The corresponding unconformity separates the Lower and Upper Paleozoic strata and represents the surface of the tectonic event known as the Kwangsian Orogeny, which was thought to be the Caledonian Orogeny occurring in the South China Plate.The process of the Kwangsian Orogeny, especially its uplift movement pattern during the tectonic events across the Cathaysia Block, was analyzed based on Ordovician biofacies and lithofacies and revealed that the Kwangsian Orogeny originated along the southeast coast of China in the Ordovician and developed stepwise in a northwest direction. However, the deposition process after the Kwangsian Orogeny is still poorly understood for the reason of rare fossil records or poor horizons recognized overlying the Kwangsian Orogeny deposits. As a result, when and how did the Devonian transgression and deposition occur are not known yet. The study on Devonian plants and near-shore depositions is required to solve the problem. Recently, the Devonian work group of Nanjing Institute of Geology and Palaeontoloy, Chinese Academy of Sciences, led by Prof. Xu Hong-He, including Prof. Wang Yi, Dr. Tang Peng, Dr. Fu Qiang and PhD student Wang Yao, for the first time, discovered the typical Lower Devonian plants from the Yangling Psephyte, Chongyi, southern Jiangxi Province, China, which palaeogeographically belongs to the Cathaysia Block of the South China Plate. As a result, the Yangling Psephyte is dated as Pragian (Early Devonian). Additionally, combined with 23 horizons and 52 Devonian plant fossil localities in southern China reported in previous studies, the stepwise pattern of Devonian transgression and deposition after the Kwangsian Orogeny is recognized. It is indicated that the transgression and deposition started no later than the Pragian Stage, continued until at least the Late Devonian and gradually strengthened northeastwards from the Early Devonian to the Late Devonian. Mr. Lei Han-Sheng and Chongyi Geology and Mineral Bureau, Jiangxi Province are grateful for help in fieldwork in the Yangling National Geopark. The study used Devonian plant fossil records to discuss the reginal geology and related palaeogeographical issues and is online published in Palaeogeography, Palaeoclimatology, Palaeoecology, as below. Article information: Xu H-H, Wang Y, Tang P, Fu Q, Wang Y. 2018. Discovery of Lower Devonian plants from Jiangxi, South China and the pattern of Devonian transgression after the Kwangsian Orogeny in the Cathaysia Block. Palaeogeography, Palaeoclimatology, Palaeoecology. https://doi.org/10.1016/j.palaeo.2018.11.007
    2019-01-24
  • Diversification of the eukaryotic life during the late Paleoproterozoic (~1700 Myr ago)

      Archaea, bacteria and eukaryotes constitute the cellular life on our planet, but all complex life on Earth are eukaryotes with nuclei inside cells. Therefore, the origin and early evolution of eukaryotes is one of the most puzzling evolutionary events in the history of life on Earth, and has been a hot topic in evolutionary biology and paleobiology. Available fossil evidences demonstrate that eukaryotes already appeared during the late Paleoproterozoic around 1,700 million years ago. However, convincing eukaryotic fossil records are scarce, so little is known about early diversity and cellular development of eukaryotes during the Paleoproterozoic.  
      Recently, an international research group led by Prof. ZHU Maoyan from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, discovered diverse eukaryotic microfossils from the late Paleoproterozoic sedimentary rocks (1,700 Ma) in the Yanshan Range, North China. The new eukaryotic fossil assemblage represents the earliest diverse eukaryotes on Earth so far, providing new insights into the origin and early evolution of the eukaryotic life. 
      The reported fossils were recovered by techniques of palynological maceration from the black shales of the late Paleoproterozoic Changzhougou and Chuanlinggou formations (1.67-1.64 Ga) in the Yanshan area. The fossil assemblage is composed of beautifully preserved organic-walled tiny microfossils which are predominated by spheroidal unicellular fossils with less abundant process-bearing, colonial and filamentous forms, and are attributed to 14 genera and 15 species with 2 newly described taxa. Among them, 10 species are interpreted as eukaryotic species (including 6 convincing and 4 ambiguous species) based on a combination of large cell dimensions and complex morphological characteristics, such as reticulate sculpture, concentric striations, tubular extensions, equatorial flanges and large internal bodies. The complex morphology and diversity revealed by these unicellular eukaryotes suggests a complexity of eukaryotic cellular development (e.g. cytoskeleton, endomembrane system) and a moderate diversification of eukaryotic life by the late Paleoproterozoic, comparable to that during the Mesoproterozoic.  
      The new finding is recently published by the international geological journal Precambrian Research. This study was supported by the Strategic Priority Research Program (B) of CAS, the National Natural Science Foundation of China, and the Swedish Research Council.Reference:Miao L, Moczydlowsk M, Zhu S, Zhu M, 2019. New record of organic-walled, morphologically distinct microfossils from the late Paleoproterozoic ChangchengGroup in the Yanshan Range, North China. Precambrian Research, 321: 172-198. DOI: 10.1016/j.precamres.2018.11.019.
      Organic-walled microfossils from the c. 1.7 Ga Changzhougou and Chuanlinggou Formations
      The diversity, relative abundance and stratigraphic ranges of microfossils in the study  
    2019-01-17
  • New Integrative Stratigraphy and Timescale for China Released
    New integrative stratigraphy and timescales for 13 geological periods in China from the Ediacaran to the Quaternary have recently been published in a special issue of SCIENCE CHINA Earth Sciences.
      New integrative stratigraphy and timescales for 13 geological periods in China from the Ediacaran to the Quaternary have recently been published in a special issue of SCIENCE CHINA Earth Sciences.
      The research summarizes the latest advances in stratigraphy and timescale as well as discusses the correlation among different blocks in China and with international timescales. The issue was edited by Prof. SHEN Shuzhong and Prof. RONG Jiayu of the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences.
      The stratigraphic record represents a massive archive for illuminating the structure and dynamics of various biological and environmental events in deep time. Consequently, establishing timescales provides a means for precisely calibrating various major geologic and biological events. Such timescales also serve as an important reference for geological mapping in China and for intercontinental and regional correlations, which benefit all geologic disciplines and the exploration of natural resources.
      Over the last decade, new technologies and more high-resolution biostratigraphic work have helped improving the formulation of stratigraphic frameworks and timescales in China. This special issue highlights these advances. 
      The issue also suggests that further refinement of chronostratigraphy and timescales in China should focus on high-quality systematic taxonomic studies of different fossil groups, using technologies including: high-resolution biostratigraphy; multidisciplinary approaches including high-precision geochronology, isotope chemostratigraphy, magnetostratigraphy, and astronomical cyclostratigraphy etc.; and quantitative stratigraphy and temporal and spatial distrbutions of natural resources based on big data.
      The International Commission on Stratigraphy (ICS) was founded in 1965. Its initial priority was to establish a precisely defined chronostratigraphic system globally applicable to all geoscientific fields. According to this system, 11 of 72 defined Global Stratotype Section and Points (GSSPs) are in China.  
      This research is supported by the National Natural Science Foundation of China, the Strategic Priority Research Program (B) and the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences.
      Reference: https://doi.org/10.1007/s11430-018-9280-6  
    2019-01-16