• Earliest flower bud fossil from 1.25 million years ago discovered in China
    Chinese researchers have unveiled the earliest flower bud fossil from the Early Cretaceous (1.25 million years ago), which was found in the Yixian Formation of Lingyuan City, Northeast China's Liaoning Province, according to Nanjing Institute of Geology and Palaeontology on Monday.
      (ECNS) -- Chinese researchers have unveiled the earliest flower bud fossil from the Early Cretaceous (1.25 million years ago), which was found in the Yixian Formation of Lingyuan City, Northeast China's Liaoning Province, according to Nanjing Institute of Geology and Palaeontology on Monday.
      In the botanical sense, the word "flower" refers to the reproductive organs of angiosperm rather than a typical flower with beautiful petals.
      The fossil flower buds are oval, 17 millimeters in length, and 9 millimeters wide, on a 15-millimeter-long stalk. There is a larch-like structure at the bottom, which is covered with flower petals, the researchers said.
      The discovery of the flower bud fossil shows that the "flower" in ordinary meaning appeared in the Early Cretaceous. In addition to attracting insect pollination, another important function of the petals is to protect stamens.
      The flower bud fossil also reveals that angiosperms and insects from the Early Cretaceous are likely to have begun collaborative evolution.
      Although great diversity of reproductive organs among early angiosperms has been reported from the Yixian Formation (Lower Cretaceous) of China, no typical flower with petals has hitherto been seen from the Early Cretaceous.
      The research, jointly conducted by WangXinfrom the Nanjing Institute of Geology and Palaeontology and Chen Lijun from the Orchid Conservation & Research Center of Shenzhen, has been published in Biology.
    2022-11-23
  • 【EurekAlert】New evidence proves saccorhytus is ecdysozoan
    An international research team led by Dr. ZHANG Huaqiao from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) has used hundreds of new fossil specimens to clarify the anatomy and evolutionary affinity of Saccorhytus, originally thought to be a deuterostome.
      An international research team led by Dr. ZHANG Huaqiao from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) has used hundreds of new fossil specimens to clarify the anatomy and evolutionary affinity of Saccorhytus, originally thought to be a deuterostome.
      The study was published in Nature on Aug. 17.
      Dr. LIU Yunhuan from Chang'an University, Dr. XIAO Shuhai from Virginia Tech, Dr. Philip C. J. Donoghue and Miss Emily Carlisle from the University of Bristol, and Dr. Michael Steiner from Shandong University of Science and Technology were also involved in the study.
      Saccorhytus, which was originally described in 2017, was discovered from the Cambrian Fortunian Zhangjiagou section of southern Shaanxi Province, China. It was interpreted to be an ancestral deuterostome. It is microscopic in size—about a millimetre in diameter—and resembles a spiky, wrinkly sack. Its mouth is surrounded by radial folds, nodes, and holes that were originally interpreted as pharyngeal openings—a primitive feature of deuterostomes.
      However, the evidence supporting Saccorhytus being a deuterostome was always very weak. Were those holes around the mouth really pharyngeal openings?
      To address this question, the research team collected hundreds of new Saccorhytus specimens from the Cambrian Fortunian Zhangjiagou and Shizhonggou sections of southern Shaanxi Province. Many of the specimens were much better preserved than any seen before, thus providing new information about the anatomy and evolutionary affinity of Saccorhytus.
      Based on these discoveries, the anatomy of Saccorhytus is now clear. Saccorhytus has a millimetric, ellipsoidal body, with one half slightly wider than the other half. Its integument is two-layered and non-ciliated. The mouth is situated terminally, and is surrounded by radial folds, one circlet of circumoral protuberances, and one to five large protuberances on one side of the body; all protuberances have a central main spine flanked by two lateral spines with a closed tip.
      Four to eight pairs of body cones are bilaterally arranged around the oral-aboral axis, each with an expanded conical base that is ornamented with longitudinal folds and supports an apical spine with a closed tip. Many nodes occur on the same side of the body as the large protuberances. In addition, many small, sharp-tipped spines are positioned on the aboral side of the body. No internal biological structures are preserved and the anus is absent.
      The team interpreted the integument as cuticle rather than epidermis. This is because cuticle contains multiple sub-layers (i.e., epicuticle, exocuticle, and endocuticle), whereas epidermis contains a single, very thin layer of epithelial cells. Furthermore, cuticle is decay-resistant and has relatively high fossilization potential, whereas epidermis is soft and decays quickly after death.
      This interpretation is consistent with the abundance of Saccorhytus specimens in the studied rocks, indicating that they have relatively high preservation potential. It is also consistent with experimental taphonomy on ecdysozoans, which shows that ecdysozoan epidermis, muscles, and visceral organs decay very quickly after death, leaving only cuticular structures and intestines.
      The researchers found that the circumoral/large protuberances, body cones, and small spines are all spinose structures with closed, sharp tips. Since the body cones have no openings, they cannot be interpreted as possible pharyngeal openings. The integument represents cuticle, with no trace of cilia, implying that the underlying epidermis is non-ciliated. The mouth has now been reinterpreted as terminal rather than ventral.
      Saccorhytus has three body axes. The terminal mouth defines the oral-aboral axis; the distribution of body cones defines the left-right axis; whereas the polarized distribution of nodes and large protuberances defines the third axis. Thus, Saccorhytus belongs to Bilateria and the three body axes represent the anterior-posterior axis, left-right axis, and dorsal-ventral axis, respectively.
      Saccorhytus is different from any known bilaterians in general morphology and body plan, but the research team have been able to find four key characteristics that help address the affinity of Saccorhytus, including a terminal mouth, the presence of cuticle, non-ciliated epidermis, and the presence of radially arranged circumoral structures. This suite of characteristics generally occurs in ecdysozoans. In particular, radially arranged circumoral structures are common to Cambrian and extant ecdysozoans. In other words, evidence pointed to Saccorhytus being an ecdysozoan.
      In order to test the ecdysozoan hypothesis, the research team conducted a comprehensive morphology-based phylogenetic analysis along with several experiments to test different possibilities. In all tests, results supported the hypothesis that Saccorhytus belongs to the total-group Ecdysozoa; conversely, the deuterostome and cnidarian hypotheses were not supported.
      Saccorhytus now represents one of the earliest known ecdysozoans. Although the exact position of Saccorhytus within the total-group Ecdysozoa is unclear, the sac-like body of Saccorhytus challenges the traditional worm-like body of ecdysozoans. It also implies that the ancestor of the ecdysozoans may not be worm-like.
      All in all, the origin of the ecdysozoan body plan awaits further study of the interrelationships among the earliest known ecdysozoans in the Cambrian Fortunian Age.
      SEM images of Saccorhytus coronarius
      Artistic reconstructions and phylogenetic position of Saccorhytus coronarius. A, anterior view; B, left view; C, posterior view; D, Saccorhytus is a total-group ecdysozoan
      Contact:
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2022-08-18
  • First palynological record of Carnian Pluvial Episode from South China
    Western Sichuan Basin . Scale bar = 20 μ m . ? Fig . 2 Carnian palynofloral composition revealing paleoclimatic setting in Jiangyou area ? Fig . 3 Correlation of the carbon-isotope records and palaeoclimate proxies between eastern and western Tethys during the mid-Carnian .H/X ratio : hygrophyte/xerophyte ratio . ? Contact : LIU Yun , PropagandistEmail : yunliu @ nigpas . ac . cnNanjing Institute of Geology and Palaeontology , Chinese Academy of SciencesNanjing , Jiangsu 210008 , China.
      The Late Triassic Carnian Stage witnessed major climatic changes during the mid-Carnian (Julian 2-Tuvalian 1), known as the “Carnian Pluvial Episode” (CPE). The CPE is characterized by increased rainfall, humid and warmer climate, oceanic anoxia, carbon cycle perturbations and demise of carbonate platforms. The global extent of the CPE-related humid climate and their impact on the terrestrial ecosystem are the major highlighted issues for the studies.
      Recently, Dr. LI Liqin, Prof. WANG Yongdong and their group from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS), and Prof. Wolfram M. Kürschner from the University of Oslo, investigated the palynoflora from the Ma’antang Formation at Ma’antang section in Jiangyou area, western Sichuan Basin, and reconstructed Carnian paleovegetation and paleoclimatic setting in this area. The research results were recently published in Review of Palaeobotany and Palynology, an international journal.
      The Ma’antang section in the Jiangyou area is the type section the Ma’antang Formation. The previous ammonite and conodont studies have established a relatively reliable geological age frame work for this formation. Diverse and well-preserved sporomorphs were identified from the Ma'antang Formation at Ma'antang section, and two palynological assemblages were distinguished.
      The study reveals dominance of fern spores (represented by Dipteridaceae/Matoniaceae) in the Ma’antang palynoflora, especially in the middle part of the Ma’antang Formation. Lycopsid spores and gymnosperm pollen (including conifers, cycadophytes/ginkgophytes and seed ferns) are much less abundant. This palynofloral composition reflects a general humid climate setting in the western Sichuan Basin during the Carnian. Overwhelming predominance of wet Lowland SEG and hygrophyte elements, and increased Lowland/Hinterland as well as hygrophyte/xerophyte ratios observed in Units 2-4 of the Ma’antang Formation, suggesting intensified humidity during the Julian 2 in this area. This study correlates well with observations from North China as well as western Tethys, thus further supports a global nature of humid climate associated with the CPE.
      This study presents the first palynological evidence for vegetation changes and humid climate during the CPE in South China, providing important evidence for better understanding the terrestrial vegetation response to the CPE from the eastern Tethys area.
      This research was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program (B) of the Chinese Academy of Sciences, and the State Key Laboratory of Palaeobiology and Stratigraphy.
      Reference: Li, L.Q., Kürschner, K.M., Lu, N., Chen, H.Y., An, P.C., Wang, Y.D.*, 2022. Palynological record of the Carnian Pluvial Episode from the northwestern Sichuan Basin, SW China. Review of Palaeobotany and Palynology, 304: 104704. https://doi.org/10.1016/j.revpalbo.2022.104704.
       
      Fig. 1 Representative fossil spores from the Ma’antang Formation at Jiangyou, western Sichuan Basin. Scale bar= 20 μm.
       
      Fig. 2 Carnian palynofloral composition revealing paleoclimatic setting in Jiangyou area
       
      Fig. 3 Correlation of the carbon-isotope records and palaeoclimate proxies between eastern and western Tethys during the mid-Carnian. H/X ratio: hygrophyte/xerophyte ratio.
       
      Contact:
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2022-07-18
  • Comprehensive progress has been made on the Late Cretaceouspollen group of Triprojectacites
    Triprojectacites is an extinct fossil pollen group characterized by three projections at the equator, which mainly thrived during the Late Cretaceous. The Northern Hemisphere palynofloras during the Late Cretaceous can be divided into a Normapolles province and an Aquilapollenites province, the latter of which is represented by the existence of Triprojectacites.
      Triprojectacites is an extinct fossil pollen group characterized by three projections at the equator, which mainly thrived during the Late Cretaceous. The Northern Hemisphere palynofloras during the Late Cretaceous can be divided into a Normapolles province and an Aquilapollenites province, the latter of which is represented by the existence of Triprojectacites. Northeast China constitutes an important part of the Aquilapollenites Provincein yielding abundant fossils of this special pollen group. This pollen group is of great significance in the study of stratigraphic division and correlation of the Upper Cretaceous, palaeoecology and palaeoclimate during that timefor its unique morphology, high diversity, short distribution, and rapid evolution.
      However, due to the complexity in morphology, it is hard to be correctly observed, described and measured, resultingin a mess of its systematic classification and identification, which then has seriously hindered its scientific applications.
      Recently, WU, Yixiao, a Ph.D. candidate in Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), with her supervisor, Prof. LI, Jianguo, and others, carried out a detailed research on the morphology, systematics, geological distribution, and evolution of Triprojectacites based on the material froma scientific drilling well, SK-1, in the Songliao Basin. A series of results has been approached and published in international journals Grana and Cretaceous Research.
      The SK-1 well in the Songliao Basin is ideal for the study of Triprojectacites for its highly detailed research, particularly the high-precision chronological framework. A total of 101 samples have been checked from the well to observe pollen morphology under optical, scanning electron, and transmission electron microscopes using single-grain technology. The morphological features of Triprojectacites have been clarified, including its shape, polarity, aperture, ornamentation and wall structure. A standardized morphological terminology and measuring method have been proposed. Finally, eight genera were screened out from the thirty-nine genera that have been proposed in relation with Triprojectacites.
      A classification system at generic level of Triprojectacitesis established. The composition and distribution of generaand species of Triprojectacites was investigated through the SK-1 well, exhibiting a five-phase evolution of Triprojectacites in the Songliao Basin as occurrence, radiation, steady development, climax, and extinction. During its evolution, Triprojectacites tend to be larger in size, more robust and complicated in ornamentation, and bearingaccessory structures.
      These research advances have laid a solid foundation for the research andapplication of Triprojectacites in species classification and evolution, and will promote its use in the study of global division and correlationof terrestrial Cretaceous strata, palaeoecology, and palaeogeography as well.
      These studies were jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences and the National Natural Science Foundation of China.
      Rereference:
      Wu, Y., Li, J., 2022. Genus classification of Triprojectacites Mtchedlishvili, 1961 emend. Stanley 1970. Grana, 61(3): 161–181. https://doi.org/10.1080/00173134.2022.2050804.
      Wu, Y., Li, J., Lin, M., & Koppelhus, E., 2022. Triprojectacites in the Songliao Basin, Northeast China: Systematics, biostratigraphy and evolution. Cretaceous Research, 135: 105193. https://doi.org/10.1016/j.cretres.2022.105193.
      Figure 1 SEM, TEM images of major ornamentationtypes in Triprojectacites
      Figure 2 Genera and species diversity of Triprojectacites in the Songliao Basin
      Figure 3 Evolution of each genera and species of Triprojectacites in the Songliao Basin
       
      Contact:
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2022-07-15
  • A new Early Ordovician Lagerst?tte reveals the early stage of the Great Ordovician Biodiversification Event
    The reconstructed complex ecosystem based on the present Liexi fauna provides new evidence for the significant biotic turnover from Cambrian to the Palaeozoic evolutionary faunas, by showing a mixture of Cambrian relics, and the Ordovician new arrivals.
      In the 1980s, the famous palaeontologist Prof. Sepkoski proposed the diversity curve of the marine animal, recognized three evolutionary faunas, and proposed the concept of Ordovician radiation. From the beginning of the Ordovician, marine life started its great radiation, as manifested by the rapid appearance of new orders, families, and genera, together with the replacement of existing groups. The Great Ordovician Biodiversification Event (GOBE) constructed the essential framework of the Palaeozoic Evolutionary Fauna, while the Cambrian faunas dominated by the arthropods were replaced by the Palaeozoic faunas represented by the filter feeders and reef-forming organisms.
      GOBE was primitively studied and defined with the skeletonized taxa, rather than the non-mineralized taxa. The exceptionally preserved Lagerstatten have been assessed as reflecting the living community, providing new evidence to know the Ordovician marine world. However, only several Ordovician Lagerst?tten have been discovered before, especially in the Early Ordovician. Recently, a new Lagerstatte, Liexi fauna, was reported by the research team from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), Hunan Museum and Central South University, from the Lower Ordovician of Yongshun country, Hunan Province. This work has been published online in Proceedings of the Royal Society B.
      The Liexi fauna has been discovered from the Madaoyu Formation of Lower Ordovician near the Liexi village, Yongshun county, Hunan Province. The conodont and graptolite assemblages indicate an age of mid-Florian, Early Ordovician, which is slightly younger than the Fezouata biota from Morocco and the Afon Gam biota from Welsh. Most of the documented fossiliferous Early Ordovician Lagerstatten globally are interpreted to occur in high latitude regions, such as the Fezouata biota near the South Pole, and the Afon Gam biota from North Wales at a palaeolatitude of 60°S. During the Early Ordovician, South China was thought to be a typical tropical palaeogeographical setting. In contrast to some other Ordovician Lagerstatten preserved in restricted or anoxic environments, the depositional environment of the Liexi fauna is interpreted to be offshore to the lower shoreface, following the palaeogeographic setting.
      The Liexi fauna includes up to 11 phyla of marine animals. The fauna is characterized by abundant, diverse biomineralized fossils along with the exceptional preservation of some non-mineralized tissues and groups. In addition to rich palaeoscolecidans and diverse trilobites (including the digestive tract preservation), the fauna also contains graptolites, extraordinarily complete echinoderms, exceptionally-preserved sponges, possible Ottoia, machaeridian polychaetes, and other rare biomineralized specimens, signalling a flourishing Early Ordovician marine fauna. A biologically complex and complete marine ecosystem with diverse organisms and varied lifestyles is proposed here, including endobenthic, sessile benthic, mobile benthic, nektonic, and planktic taxa.
      Any discoveries of Early Ordovician Lagerstatten are of significant concern for the research on the Cambrian to Ordovician faunal transition. The Liexi fauna is suggested as the age of middle Floian, probably preceding the GOBE’s primary interval of diversification by ~5–10 Myr. The reconstructed complex ecosystem based on the present Liexi fauna provides new evidence for the significant biotic turnover from Cambrian to the Palaeozoic evolutionary faunas, by showing a mixture of Cambrian relics, and the Ordovician new arrivals.
      This research is supported by CAS Strategic Priority Research Program (B) and National Nature Science Foundation of China.
      Reference: Fang, X., Mao, Y.Y., Liu, Q., Yuan, W.W., Chen, Z.Y., Wu, R.C., Li, L.X., Zhang, Y.C., Ma, J.Y., Wang, W.H., Zhan, R.B., Peng, S.C., Zhang, Y.D., Huang, D.Y.*, 2022. The Liexi fauna: a new Lagerstatte from the Lower Ordovician of South China. Proceedings of the Royal Society B, 289: 20221027. https://doi.org/10.1098/rspb.2022.1027.
       
      Fossils from the Liexi fauna
       
      Palaeoscolecidan worms from the Liexi fauna
       
      Ecological reconstruction of the Liexi fauna (Drawn by J. Sun)
       
      Contact:
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2022-07-14
  • Feathery Insulation Helped Dinosaurs Survive and Thrive: Study
    The so-called Triassic-Jurassic Extinction(~202millionyearsago) killed off the big reptiles that up until then had ruled the planet, thus clearing the way for dinosaurs to take over. But why did dinosaurs thrive when other creatures died?
      The so-called Triassic-Jurassic Extinction(~202millionyearsago) killed off the big reptiles that up until then had ruled the planet, thus clearing the way for dinosaurs to take over. But why did dinosaurs thrive when other creatures died?
      Now a new study led by researchers from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) and Columbia University answers this question.
      It reveals that Triassic dinosaur species—then a minor group largely relegated to the higher latitudes—regularly endured freezing conditions, suggesting they were well-adapted to the cold in a way that non dinosaurian species were not. Thus, when the Central Atlantic Magmatic Province (CAMP) caused years to decades of global volcanic winter at the end of the Triassic, dinosaurs were able to survive while then-dominant reptiles could not.
      The study was published in Science Advances on July 2.
      The researchers’ conclusion relied on two key findings:
      First, the researchers found physical evidence of dinosaur footprints from the Junggar Basin in Xinjiang Uygur Autonomous Region of northwestern China. During the Late Triassic to Early Jurassic, this region was located at about 71 degrees north, well above the Arctic Circle. The footprints showed that dinosaurs were present along shorelines.
      Second, when the researchers analyzed deep lake deposits, they found abundant pebbles up to about 1.5 centimeters in diameter within normally fine sediments. Far from any apparent shoreline, the pebbles had no business being there. That left only one plausible explanation: They were ice-rafted debris (IRD).
      Finding evidence of IRD was crucial to the study because it provided important climate clues.
      IRD is created when ice abuts a coastal landmass and incorporates bits of underlying rock as it freezes. At some point the ice becomes unmoored and drifts into the adjoining water body. When it melts, the rocks drop to the bottom, mixing with normally fine sediments. Geologists have extensively studied ancient IRD in the oceans, where it is deposited by glacial icebergs, but rarely in lake beds; the Junggar Basin discovery adds to the scant record.
      The researchers said the pebbles were likely picked up during winter, when lake waters froze along pebbly shorelines. When warm weather returned, chunks of ice floated away with pebbles in tow and later dropped them.
      “This shows that these areas froze regularly and the dinosaurs did just fine,” said study co-author Dennis Kent, a geologist at Columbia University’s Lamont-Doherty Earth Observatory.
      The researchers then used phylogenetic bracket analysis to conclude that the dinosaurs were primitively insulated with feathers. This insulation allowed them to adapt to intense volcanic winters and cold polar conditions so they could take advantage of the Arctic’s deciduous and evergreen vegetation.
      “The key to their eventual dominance was very simple. They were fundamentally cold-adapted animals. When it got cold everywhere, they were ready, and other animals weren't,” said Paul Olsen from Columbia University. 
      While the end of the Triassic is often associated with deadly temperature spikes due to high carbon dioxide concentrations from volcanic eruptions, those same eruptions also deflected a great deal of sunlight, leading to volcanic winters.
      “Severe wintery episodes during volcanic eruptions may have brought freezing temperatures to the tropics, which is where many of the extinctions of big, naked, unfeathered vertebrates seem to have occurred,” said SHA Jingeng from NIGPAS. “Where as our fine feathered friends acclimated to colder temperatures in higher latitudes did okay.”
      After the biological extinction event at the end of the Triassic, dinosaurs rapidly increased in size and expanded their geographic range, with the total number of dinosaurs nearly doubling. From then on dinosaurs started their135-million-year-long terrestrial domination of Earth.
      Fig. 1 The supercontinent of Pangaea 202 million years ago, shortly before the Triassic-Jurassic Extinction. (Image by Olsen et al.)
       
      Fig. 2 A shale cliff in the Junggar Basin in northwestern China, where scientists found ice-rafted pebbles amid otherwise fine-grained sediments. (Image by Paul Olsen)
       
      Story Source: 
      Materials provided by Columbia Climate School. Original written by Kevin Krajick. Note: Content may be edited for style and length.
      Contact:
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
      Nanjing, Jiangsu 210008, China
    2022-07-11
  • Massive carbon emission caused marine anoxia and biodiversity loss 300 million years ago
    What would happen in the near future with continued global warming? What environmental conditions would the life on Earth most likely confront? The episodes of climate changes in the Earth’s deep past, similar to the current global warming, may provide valuable clues to these questions.
      What would happen in the near future with continued global warming? What environmental conditions would the life on Earth most likely confront? The episodes of climate changes in the Earth’s deep past, similar to the current global warming, may provide valuable clues to these questions.
      A recent study led by scientists from China, U.S., and New Zealand reveals that an abrupt warming linked to massive carbon emission during an icehouse climate state caused approximately 20% of anoxic areal extent of the seafloor, and significant biodiversity drop. The finding was published by the Proceedings of the National Academy of Sciences of the United States of America on May 2, 2022.
      As is known, we are currently living under the Cenozoic icehouse climate that has started since 34 Myr ago. However, global temperature rises rapidly under this icehouse over a couple of centuries, in tandem with accelerated ablation of polar glaciers, rising sea-level, and aggravating marine de-oxygenation, and undoubtedly leading to a significant drop in biodiversity. Where would the global warming lead us to in the future? There are substantial uncertainties regarding the modeling results based on current observations, which drive the current focus on understanding past episodes of carbon emission and ocean deoxygenation, particularly under an icehouse climate state.
      The Late Paleozoic Ice Age (LPIA, between 360 and 280 million years ago) is the longest-lived and the only icehouse that recorded the transition from icehouse to greenhouse climate states since the occurrence of advanced plants and terrestrial ecosystem. The LPIA is also the only geological period that is featured by low atmospheric CO2 and high O2 concentrations, highly comparable to those of the modern day. It is, therefore, critical to study carbon emissions and their consequences during the LPIA for better understanding the processes and feedbacks of the icehouse Earth system, and thus for more precisely predicting the future environmental and biodiversity changes.
      A international research team led by Dr. CHEN Jitao from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), Dr. WANG Xiangdong from the Nanjing University, and Dr. Isabel P. Montanez from the University of California, Davis studied the Carboniferous strata from the southern China for over 10 years, with respect to sedimentology, stratigraphy, paleontology, and geochemistry.
      The Naqing and Narao sections from the Luodian region, Guizhou Province crop out continuous Carboniferous carbonate successions that register geochemical signal of sea water.
      Scientists collected samples by every 20 cm for over 40-m-thick strata from the two sections and carried out carbon and uranium isotopes to explore the global carbon cycling and marine anoxia. "We utilized global carbon cycle model (LOSCAR) and paleo carbon dioxide concentrations to simulate a total amount of 9,000 Gt C emitted over 300 kyr, causing an increase in sea-surface temperature by ~4℃", CHEN says.
      "We also modelled an increase in areal extent of the anoxic seafloor from 4% to 22%, causing a dramatic decrease in biodiversity" CHEN Added, "and finally, we performed climate model simulations using the fully coupled Community Earth System model (CESM) to explore the potential mechanisms for the marine anoxia, which are linked to enhanced thermocline stratification and increased nutrient fluxes during the warming."
      The study further finds that warming-induced marine anoxia may be more pronounced in a glaciated than in an unglaciated period.
      Reference: Chen, J.T., Montanez, I.P., Zhang, S., Isson, T.T., Macarewich, S.I., Planavsky, N.J., Zhang, F., Rauzi, S., Daviau, K., Yao, L., Qi, Y.P., Wang, Y., Fan, J.X., Poulsen, C.J. Anbar, A.D., Shen, S.Z., Wang, X.D., 2022. Marine anoxia linked to abrupt global warming during Earth’s penultimate icehouse, PNAS, https://doi.org/10.1073/pnas.2115231119.
      Fig. 1. An abrupt global warming occurred at ~304 Ma under the Carboniferous icehouse climate state, consistent with doubling of atmospheric carbon dioxide, significant negative excursion in carbon isotopes, sea-surface temperature increase, and drop in biodiversity.
      Fig. 2. Carbon and uranium isotopes recorded in the Naqing section, Guizhou Province, southern China, showing remarkable negative excursions across the Kasimovian-Gzhelian boundary. Modeling results suggest a distinct perturbation in global carbon cycle and an increase in marine anoxia.
      Fig. 3. Comparison between the KGB warming event during the late Carboniferous icehouse and greenhouse C-perturbation events over the last 300 Myr, indicating that the KGB warming had a more extreme impact on the marine redox landscape relative to its rate of C injection and SST increase than the other events.
      Contact: 
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn 
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences 
      Nanjing, Jiangsu 210008, China
    2022-05-05
  • Paleogeographic framework of northeastern Gondwana in the late Paleozoic
    Assembly of Gondwana commenced in the Neoproterozoic with final disassembly of the supercontinent completed by the Cretaceous. The configuration of major continental blocks (e.g., India, Australia, East Antarctica, and Africa) of Gondwana has been well reconstructed. However, paleopositions of some small continental fragments along the periphery of Gondwana are still in controversy.
      Assembly of Gondwana commenced in the Neoproterozoic with final disassembly of the supercontinent completed by the Cretaceous. The configuration of major continental blocks (e.g., India, Australia, East Antarctica, and Africa) of Gondwana has been well reconstructed. However, paleopositions of some small continental fragments along the periphery of Gondwana are still in controversy.
      The Baoshan, Tengchong, Lhasa, South Qiangtang, and Sibumasu terranes were located along the northern margin of Gondwana before late Early Permian rifting. A substantial amount of work has been carried out, aiming at reconstructing the paleopositions of these terranes from various disciplines such as sedimentary provenance, paleomagnetism, and paleobiogeography. These studies led to various paleogeographic models of northeastern Gondwana.
      Recently, a paleogeographic study based on detrital zircon U-Pb ages and Hf isotopic values from Paleozoic strata of northeastern Gondwana, which is conducted by GAO Biao, his advisor Prof. CHEN Jitao, and Prof. QIE Wenkun from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), in collaboration with the scientist Prof. WANG Xiangdong from Nanjing University. Primary component analysis (PCA) was used to visualize the relative relationship between these terranes and East Gondwana, in addition with the glacier distribution pattern on northeastern Gondwana in the late Paleozoic. The research achievements were published in the international journal Sedimentary Geology.
      Based on a total of 8209 detrital zircon U-Pb ages and 1606 zircon Hf isotopic values from Paleozoic strata of northeastern Gondwana, a new paleogeographic model has been reconstructed. It indicates that the South Qiangtang, Baoshan, and part of Sibumasu were outboard of the northern margin of Indian Gondwana during the Paleozoic, whereas the Lhasa and Sumatra terranes were located along the northern margin of Australia. Based on provenance shifts of late Paleozoic glaciogenic sedimentary rocks in northeastern Gondwana, two main ice sheets are hypothesized to have developed during the late Paleozoic. This study further confirms the model of a multicenter glacier distribution pattern on Gondwana during the late Paleozoic ice age from a perspective of provenance.
      The research is supported by the Strategic Priority Research Program of the Chinese Academy of Sciences, the National Natural Science Foundation of China, and the Second Tibetan Plateau Scientific Expedition and Researh Program. This is a contribution to IGCP 700 and DDE (Deep-time Digital Earth) projects.
      Reference: Gao, B.*, Chen, J.T.*, Qie, W.K., Wang, X.D., 2022. Revisiting the paleogeographic framework of northeastern Gondwana in the late Paleozoic: implications from detrital zircon analysis. Sedimentary Geology. Available online 11 April 2022. https://doi.org/10.1016/j.sedgeo.2022.106144.
      Schematic geological map of Southeast Asia and detrital zircon samples locations
      Primary component analysis (PCA) of detrital zircon characteristic age population
       
      Reconstruction of northeastern Gondwana with regional ice centers during the late Paleozoic ice age
      Contact:  
      LIU Yun, Propagandist
      Email: yunliu@nigpas.ac.cn 
      Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences 
      Nanjing, Jiangsu 210008, China
    2022-04-18
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