Research Progress---- Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences

Breakthrough Study Confirms Lhasa Terrane Originated from Northeastern India Body

The study led by Profs WANG Guangxu, ZHAN Renben from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), along with their colleagues provides compelling evidence to resolve this longstanding controversy. Their findings were published in Gondwana Research.The Lhasa terrane, once part of Gondwana until the Permian/Triassic, rifted away and accreted to Eurasia, forming a core part of the Tibetan Plateau. Pinpointing its palaeogeographical position is essential for understanding both the reconstruction of Gondwana and the plateau’s evolution. However, considerable controversy persists over its exact position before separation, with geochemical and isotopic data suggesting ties to Australian, Indian or African sections of eastern Gondwana.The study led by Profs WANG Guangxu, ZHAN Renben from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), along with their colleagues provides compelling evidence to resolve this longstanding controversy. Their findings were published in Gondwana Research.Researchers systematically used newly acquired, palaeobiogeographically sensitive fossils from the Baingoin area of central Tibet to determine the terrane’s affinities. This late Darriwilian–Sandbian (Middle–Late Ordovician, ca. 457–453 Ma) biota lay along a palaeolatitudinally differentiated biotic gradient, indicative of a distinctly closer palaeobiogeographical affinity to northeastern India than to Australia or Africa.“This finding, confirmed by a critical review of existing fossil and geochemical data, strongly supports a northeastern Indian origin of the Lhasa terrane,” says WANG.Financial support for this study came from the National Key Research and Development Program of China, and the State Key Laboratory of Palaeobiology and Stratigraphy (LPS).Reference: Wang, G.X., Zhan, R.B., Jin, J., Chen, Z.Y., Percival, I.G., Wei, X., Liang, Y., Cui, Y.N., Wang, Y. & Zhang, Y.T. 2025. Northeastern Indian origin of the Lhasa terrane. Gondwana Research, 147, 184-191. https://doi.org/10.1016/j.gr.2025.06.010.Key fossils from the basal Dongka Group (upper Darriwilian–Sandbian) of the Baingoin area, central Tibet (northern Lhasa terrane)Results of the cluster analysis (a) and a Sandbian (early Late Ordovician) reconstruction of eastern Gondwana (b), supporting a northeastern Indian origin of the Lhasa terrane.

2025-07-11

“Explosive” development of Ordovician reefs may be an illusion of preservation bias

For several decades, the scientific consensus held that reef-building organisms like stromatoporoid sponges, corals, and bryozoans underwent sudden "explosive" development during the Great Ordovician Biodiversification Event (GOBE) in the late Darriwilian (Middle Ordovician), dramatically increasing marine biodiversity. However, recent discoveries by researchers from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences challenged this narrative. The team identified the oldest known stromatoporoid fossils (~480 million years old) in Yuan'an, Yichang, Hubei Province—pushing the record of stromatoporoid reefs back to Early Ordovician. Surprisingly, this was followed by a 20-million-year "reef gap" where fossil records nearly vanished, raising critical questions: Why did reef records disappear after the Early Ordovician? Why did reef-building organisms seemingly vanish for 20 million years? And why did they suddenly "explode" in diversity during the late Darriwilian?On June 30th, researchers led by Li Qijian (NIGPAS), Jeon Juwan (Korea University), and Lee Jeong-Hyun (Chungnam National University) integrated stratigraphic sequences and fossil occurrence data from major paleocontinents. Data based correlation analyses revealed that the apparent "explosion" may not reflect true evolutionary dynamics of reef ecosystem during the late Middle Ordovician. Instead, it likely stems from a global sea-level fall (~475–460 million years ago) that erased shallow marine carbonate environments—critical for reef development and fossil preservation. This regression caused widespread erosion, wiping out fossil records of early reef-builders. When sea levels rose again in the mid-late Darriwilian, already-diversified organisms rapidly recolonized newly flooded habitats, creating an illusion of sudden diversification.This phenomenon—termed the "Sppil-Rongis effect" (the inverse of the Signor-Lipps effect)—demonstrates how improved preservation conditions can generate false signals of abrupt biological radiation. Critically, the study reframes the GOBE not as a discrete "explosive event" but as part of a continuous evolutionary trajectory, repeatedly interrupted and reshaped by sea-level fluctuations and preservation biases. This supports the view that the Cambrian Explosion and Ordovician Biodiversification constitute a single extended diversification process.The research underscores how preservation biases fundamentally distort our understanding of evolutionary history, emphasizing the need to disentangle true biological signals from geological artifacts in reconstructing Earth's life story.Fig. 1. Diversity (number of genera) of reef-building metazoans (stromatoporoids, corals, and bryozoans) and reef occurrences through time.Fig. 2. Global sea-level curve during the Ordovician, schematic stratigraphic columns for Laurentia and Sino-Korean Block, and carbonate and siliciclastic sedimentary rock area.Fig. 3. Global paleogeographic maps of the Early, Middle, and Late Ordovician, showing the distribution of reef-building metazoans (stromatoporoids, tabulate and rugose corals, and bryozoans).Fig. 4. Schematic illustration of the Sppil–Rongis effect in reef evolution, coupled with sea-level changes.

2025-07-07

Junggar Basin Sediments Reveal Interplay Between Solar System Chaos and Earth’s Carbon Cycle

Researchers from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences and Columbia University, along with their collaborators, have analyzed sediments from the terrestrial Sangonghe Formation (Late Early Jurassic) in China’s Junggar Basin, revealing information both on Solar System chaos and the global carbon cycle. Their findings were published in the Proceedings of the National Academy of Sciences (PNAS).Researchers from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences and Columbia University, along with their collaborators, have analyzed sediments from the terrestrial Sangonghe Formation (Late Early Jurassic) in China’s Junggar Basin, revealing information both on Solar System chaos and the global carbon cycle. Their findings were published in the Proceedings of the National Academy of Sciences (PNAS).The team conducted a multidisciplinary study of the Junggar Basin’s well-preserved lake sediments, combining astrochronostratigraphy, sedimentology, geochemistry, and palynology. Their analyses uncovered a shifting long-term rhythm in the orbits of Mars and Earth—known as the Mars–Earth grand eccentricity cycle—which governs how elliptical Earth’s orbit becomes over multi-million-year timescales. These orbital changes affect how much sunlight Earth receives and, in turn, influence climate and the global carbon cycle.The study identified a previously unrecognized 1.6-million-year cycle in the carbon isotope record, distinct from the current 2.4-million-year grand eccentricity cycle. This variation provides concrete geological evidence of Solar System chaos—the idea that gravitational interactions among planets can lead to unpredictable orbital shifts over deep time. The findings extend our understanding of planetary behavior beyond the 60-million-year limit of modern orbital simulations.In parallel, the study sheds light on the Earth’s carbon cycle response during a major climate event: the Jenkyns Event, a global warming episode approximately 183 million years ago. The researchers linked this event to the 1.6-million-year orbital cycle and found that carbon isotope signals recorded in the shallow-lake environment of the Junggar Basin likely reflect changes in atmospheric CO₂ composition driven by orbital dynamics. Unlike marine and deep lake settings, where carbon fluctuations appear amplified, the Junggar Basin may preserve a more representative signal of the global carbon system.This research demonstrates how ancient sediments can serve as a window into both planetary dynamics and Earth system processes, helping scientists constrain the evolution of the Solar System and better understand how orbital variations can drive climate and carbon cycle changes on Earth.By bridging insights from planetary science and paleoclimatology, the study contributes to refining astronomical models, validating gravitational theories, and improving our knowledge of Earth’s long-term climate sensitivity.Reference: Fang Yanan, Olsen P. E., Sha Jingeng, Whiteside J. H., Chengguo Guan, Ikeda M., Li Sha, Zheng Daran, Zhang Haichun, Wang Bo, 2025. Jurassic constrains on the chaotic Mars-Earth eccentricity cycle linked to the volcanically induced Jenkyns event. PNAS, https://doi.org/10.1073/pnas.2419902122.Fieldwork photo of Yanan Fang and Paul Olsen in the Sangonghe Formation at the Haojiagou section in the Junggar BasinLocation map of the present-day and Early Jurassic Junggar BasinLithologic column of the Sangonghe Formation tuned to the 400-kyr eccentricity cycle (A), relative spore-pollen abundance (B), color (C), sedimentary facies and relative lake-level curve (D), total organic carbon (TOC) content (E), organic carbon isotope (F), and corresponding 1.6-Myr Mars-Earth super-long eccentricity and 400-kyr Jupiter-Venus eccentricity filteringAge distribution of the Karoo-Ferrar Large Igneous Province correlated with organic carbon isotopes from the Junggar Basin tuned to the 400-kyr eccentricity cycle, organic carbon isotopes from Mochras Farm (UK), biogenic silica flux from Inuyama (Japan), and magnetic susceptibility from Sancerre (France). All sections are aligned at the most negative T-OAE carbon isotope point, with the time scale derived from the Inuyama astronomical age model.Comparison of Mars-Earth super-long eccentricity cycles in astronomical solutions with geological records.

2025-07-02

Multidisciplinary Evidence Reveals Climate–Carbon-Cycle Interactions During the Carnian Pluvial Episode

The Mesozoic Era was marked by long-term greenhouse climates and repeated hyperthermal events—periods of rapid global warming—that profoundly affected life, ecosystems, and petroleum systems. The Carnian Pluvial Episode (CPE, ~234–232 Ma), is characterized by global warming, intensified hydrological cycling, increased continental weathering and erosion, and expanded marine anoxia. Popularized as a “million‑year global rain” (Marshall 2019, Nature), and often linked to dinosaur emergence, the CPE’s trigger mechanisms and climate feedback patterns have long remained controversial.A multinational team led by Prof. Bo Wang from the Nanjing Institute of Geology and Palaeontology (CAS), with collaborators from the Institute of Vertebrate Paleontology and Paleoanthropology (CAS), Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Institute of Geochemistry (CAS), Guangzhou Institute of Geochemistry (CAS), Vrije Universiteit Brussel, University of Oxford, University of Münster, Alfred Wegener Institute,reported a continuous lacustrine sequence (Dalongkou section) in the southern Junggar Basin, northwestern China. Using methods of stratigraphy, sedimentology, geochemistry, cyclostratigraphy and Earth system modeling, they systematically investigated the mechanistic origin of the CPE, climate–carbon feedbacks, and precipitation patterns. Their findings were published online on June 30, 2025 in Nature Communications.1. Mechanistic origin of the CPEHigh-resolution mercury (Hg) concentrations and isotopes reveal that approximately 38,000 years before the CPE onset, the Wrangellia Large Igneous Province (LIP) began releasing isotopically light carbon. This release corresponded with Hg anomalies and an abrupt but relatively weak negative δ13C shift (POE), coinciding with initial warming. As temperatures passed a threshold, heat-sensitive carbon reservoirs, such as sedimentary organic matter, permafrost, and especially marine methane hydrates were triggered. The sequence of events, including evidence for volcanic activity followed by a large CIE may support a scenario whereby the emplacement of the Wrangellia LIP prior to the CPE induced net positive climate–carbon-cycle feedbacks.2. Climate–carbon-cycle interaction through the CPETheir findings show that the CPE terrestrial carbon cycling, at a δ13Corg scale of ±1‰, displays an in-phase relationship with the 405-kyr long-eccentricity metronome, which appears similar to the warmhouse climate–carbon-cycle present throughout the Oligo–Miocene interval. This result, together with previous long-term carbon-isotope records, shows that such a climate–carbon-cycle interaction may have been widespread throughout the warm Mesozoic Era, including hyperthermal intervals. Therefore, this climate–carbon interaction may be the norm after the emergence of vascular plants, whereas the coldhouse climate–carbon-cycle dynamics of the earliest Pliocene may represent a more unusual situation.3. The hydrological cycle during the CPEAnalysis of palynology and Earth system model simulations reveals thatprecipitation changes during the CPE exhibited spatial heterogeneity, accompanied by a poleward shift of pre-existing precipitation zones and no evidence for global humidification. The heterogeneous pattern of precipitation changes is characterised by predominantly increased precipitation near the Equator and at high latitudes, while subtropical latitudes exhibit diminished rainfall. In contrast to previous hypotheses regarding unusual global humidification during the CPE, the integrated stratigraphy and Earth system model highlight the spatial variations in global precipitation patterns, characterised by increased aridification in continental interiors and the emergence of multiple precipitation centres in low-latitude eastern continents and polar regions, including the Arctic, northeastern Tethys, northeastern Gondwana, and the Antarctic.4. Implication for understanding past hyperthermal eventsThe CPE shares key features and perhaps driving mechanisms with several other hyperthermal events including the Triassic–Jurassic hyperthermal event, Cretaceous OAEs, as well as the Paleocene–Eocene Thermal Maximum. Moreover, during the hyperthermal events, different regions may have experienced periods of extreme drought or severe flooding, reflecting the contrasting extremes of climate. Thus, despite differences in nomenclature, these events share a fundamental nature as hyperthermal episodes. These similarities suggest that understanding their commonality might hold essential information on the nature of hyperthermal events and specifically which elements in the climate and carbon cycle contribute to these anomalously warm periods.The research was supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences.Reference: Zhao Xiangdong, Xue Naihua, Yang Hu, Zheng Daran, Peng Jungang, Frieling J., De Vleeschouwer D., Fu Xuewu, Jia Wanglu, Fang Yanan, Li Sha, Wang Meng, Zhao Xianye, Wang Qiang, Zhang Haichun, Sha Jingeng, Jenkyns H.C., Claeys P., Wang Bo (2025) Climate–carbon-cycle interactions and spatial heterogeneity of the Late Triassic Carnian Pluvial Episode. Nature Communications, https://doi.org/10.1038/s41467-025-61262-7.Fieldwork photo at the Dalongkou section, XinjiangThe integrated stratigraphy calibrated to the astronomical time scale of the Huangshanjie FormationMagnification of high-resolution data of the carbon-isotope excursions (CIEs) and model for the carbon cycle during the Carnian Pluvial EpisodeSimulated climate states before and during the Carnian Pluvial Episode

2025-06-30

Fossils of Nemejcopteris haiwangii from the “vegetational Pompeii” provides new evidence for the climbing habit in late Paleozoic plants

Climbing is a growth strategy in which plants rely on other plants or substrates for mechanical support to grow upward. Climbing plants occupy important ecological niches in natural communities and also hold significant value in horticultural landscapes. The origin of this growth habit can be traced back to the late Paleozoic, and its evolutionary diversification is closely correlated with the increasing structural complexity of forest ecosystems. However, due to the limitations of fossil preservation, direct fossil evidence of actual climbing height and ecological interactions between climbers and their host plants remains exceedingly rare in palaeobotanical studies.The early Permian fossil Lagerstätte “vegetational Pompeii” in the Wuda Coalfield of Inner Mongolia, owing to its unique mode of burial, preserves not only the external morphology and internal anatomy of plant fossils but also evidence of interactions between plants. Therefore, it often provides exceptional fossil evidence of climbing behavior in late Paleozoic plants.Recently, the research team lead by Prof. Jun Wang from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, in collaboration with colleagues from the Institute of Geology v.v.i. (Czech Academy of Sciences), the West Bohemian Museum in Pilsen, and Stanford University, conducted an in-depth study on the fern Nemejcopteris haiwangii. Their findings confirm that N. haiwangii exhibited a climbing habit. The results were published in the international journal Palaeogeography, Palaeoclimatology, Palaeoecology.Nemejcopteris haiwangii, first discovered in the Wuda “vegetational Pompeii,” was originally reconstructed as a ground-cover plant with a rhizomatous stem and upright fronds. Although previous studies identified prickle-like structures on its rachises, which could have assisted in climbing, direct evidence for this behavior had not been documented. This new study presents several exceptionally preserved specimens that clearly show physical interaction between the fronds of N. haiwangii and the trunks of Psaronius, thereby providing definitive fossil evidence of climbing behavior in this taxon.Prickles of varying sizes are present on all orders of N. haiwangii rachises, suggesting that the plant used a hook-climbing mechanism to gain support from nearby vegetation. However, compared to climbing strategies such as twining or adhesive pads, this hook-based mechanism appears relatively weak. Quadrat-based palaeoecological data further reveal that N. haiwangii fronds interacted primarily with the middle to lower portions of Psaronius trunks, suggesting a limited climbing height—likely no more than four meters. This further supports the interpretation of its weak climbing ability.Taken together, the new findings indicate that Nemejcopteris haiwangii typically grew as a ground-covering plant with a rhizomatous stem and erect fronds. However, when encountering a suitable host such as Psaronius, its fronds could bend and use the host for additional support. Contrary to the traditional view that plant climbing habits during the late Paleozoic were primarily controlled by local canopy closure, this study suggests that Nemejcopteris haiwangii could not reach the canopy and was therefore not regulated by forest canopy density. Its facultative climbing strategy more likely represents an adaptation to the periodically waterlogged conditions at the forest floor in swampy environments: when water levels rose, facultative climbers could ascend to higher positions, enabling their foliage to conduct gas exchange more effectively. This provides a novel explanation for the abundant occurrence of climbing plants in the Permo-Carboniferous wetland vegetation.This research was jointly supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, and the Youth Innovation Promotion Association of Chinese Academy of Sciences.Reference: Li F.Y., Li D.D., Votočková Frojdova J., Pšenička J., Boyce C.K., Wang J., Zhou W.M.*, 2025. Climbing habit confirmed in the early Permian zygopterid fern Nemejcopteris haiwangii and its palaeoecological significance. Palaeogeography, Palaeoclimatology, Palaeoecology. 675:113101 https://doi.org/10.1016/j.palaeo.2025.113101.Interaction between Nemejcopteris haiwangii and Psaronius. (A–C) Different portions of the same trunk, showing N. haiwangii fronds bending and leaning against the tree fern stem; (D–E) Climbing rachises of N. haiwangii and the prickles on their surface; (F–G) Ultimate and penultimate pinnae of N. haiwangiiNemejcopteris haiwangii (nh) climbing on the tree fern Psaronius (ps). (A) Drone photograph of the excavation site; (B) Crown of the host tree fern Psaronius; (C–D) Preservation of N. haiwangii mainly concentrated around the middle to lower portions of a Psaronius tree fern, field photos from 2023Quadrat-based field data showing that Nemejcopteris haiwangii primarily concentrated around the middle to lower pportions of a Psaronius tree fern. Quadrat data from 2015

2025-06-26

Study of Ancient Rocks Helps Predict Potential for Future Marine Anoxia

Earth’s current climate is considered an “icehouse climate” due to the existence of polar ice caps. This is important because previous icehouse climates can better predict how atmospheric oxygen and carbon dioxide (CO2) levels today may affect the risk of marine anoxia and subsequent marine biodiversity loss in the future.By combining these records with previously published carbonate carbon isotopes, paleo-CO2 data, and records of volcanic activity and plant evolution, the researchers quantitatively explored, through biogeochemical modeling, the global carbon cycle and marine oxygen conditions for this geological period. This work was published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).Earth’s current climate is considered an “icehouse climate” due to the existence of polar ice caps. This is important because previous icehouse climates can better predict how atmospheric oxygen and carbon dioxide (CO2) levels today may affect the risk of marine anoxia and subsequent marine biodiversity loss in the future.To understand the interplay among atmospheric oxygen and CO2 levels and oxygenation conditions in the ocean during an earlier icehouse climate, an international team led by Prof. CHEN Jitao from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences studied ancient sedimentary rocks in Naqing, South China, to analyze their chemical compositions.Specifically, the researchers derived high temporal-resolution records of carbonate uranium isotopes from a marine carbonate slope succession dating from the late Carboniferous to early Permian (310–290 million years ago). This geologic epoch is part of the Late Paleozoic Ice Age (LPIA) (360–260 million years ago), which is recognized as the longest icehouse climate since advanced plants and terrestrial ecosystems appeared.By combining these records with previously published carbonate carbon isotopes, paleo-CO2 data, and records of volcanic activity and plant evolution, the researchers quantitatively explored, through biogeochemical modeling, the global carbon cycle and marine oxygen conditions for this geological period. This work was published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).The study revealed rapid drops in levels of carbonate uranium isotopes, which occurred alongside rapid increases in atmospheric CO2 levels. This suggests that seafloor anoxia expanded even during the Phanerozoic maximum of atmospheric oxygen and the glacial peak of the LPIA.Using a carbon–phosphorus–uranium (C-P-U) biogeochemical model coupled with Bayesian inversion, the researchers quantitatively examined the interactions among marine anoxia, carbon cycling, and climate evolution during this paleo-glacial period. Model results indicated that enhanced burial of marine organic carbon likely drove the overall decline in atmospheric CO2 and the rise in oxygen levels in the atmosphere–ocean system throughout this interval. However, despite these high oxygen levels, episodic massive carbon emissions could have triggered recurrent global warming and seafloor deoxygenation.Furthermore, the team’s model showed an increase of 4–12% in the extent of the anoxic seafloor, which could have led to a pause or decline in marine biodiversity. This study emphasizes that under current icehouse conditions, which mirror the high-oxygen state of the LPIA, ongoing warming may still provoke widespread ocean anoxia.This study advances our understanding of the processes and feedback mechanisms within the Earth system during icehouse conditions, enabling more accurate projections of the future trajectory of current global warming and marine deoxygenation.Paleozoic marine biodiversity, atmospheric composition, and seafloor oxygenation historyGeochemical, geologic, and biotic records for the late Carboniferous to early Permian, showing repeated occurrences of anoxic events (AE1–5).

2025-06-24

Major research advances have been made to the Ediacaran–Cambrian Boundary in Anti-Atlas, Morocco

The Ediacaran–Cambrian transition (ECT) marks one of the most pivotal intervals in evolutionary history, characterized by the emergence and rapid radiation of multicellular life. A robust global chronostratigraphic framework is crucial for elucidating the processes underlying this major biological innovation and its relationship to coeval paleoenvironmental changes. Morocco's Anti-Atlas region preserves one of the most complete late Ediacaran to early Cambrian carbonate successions globally (Figure 1), providing an exceptional natural laboratory for such investigations. Nevertheless, the absence of definitive biostratigraphic markers and incomplete understanding of basin tectonics have resulted in persistent uncertainties regarding both the precise placement of the Ediacaran–Cambrian boundary (the Cambrian Base) and its connection to the basin's tectonic-sedimentary evolution.To address these questions, Dr. Yiwei Xiong from the Early Evolution of Earth-Life System team at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, under the guidance of Professors Bo Chen and Maoyan Zhu, collaborated with Professor El Hafid Bouougri (Cadi Ayyad University, Morocco) and colleagues. The team conducted a systematic, interdisciplinary study of the Tabia section in Morocco’s Anti-Atlas, their work yielded two key findings:First identification of four distinct tectono-sedimentary evolutionary phases in the Anti-Atlas Basin during the Ediacaran-Cambrian transition (Figure 2);A revised definition of the regional Ediacaran-Cambrian boundary.These results underwent peer review and were published in Gondwana Research on June 6, 2025.This study reveals that the Tabia Member experienced three distinct syn-rift tectono-sedimentary evolutionary stages, transitioning to a post-rift stage in the overlying Tifnout Formation (Figure 2). Systematic geochemical analyses support this interpretation. The syn-rift dolostones of the Tabia Formation display characteristically elevated ⁸⁷Sr/⁸⁶Sr ratios, positive Eu/Eu* anomalies, and significant enrichment in Mn, Pb, Fe, and Zn (Figure 3), indicating dolomitization influenced by mixed hydrothermal-seawater fluids (Figure 4). In contrast, the post-rift dolostones of the Tifnout Formation show substantially diminished hydrothermal signatures (Figure 3), consistent with seawater-dominated dolomitization (Figure 4). These contrasting geochemical patterns document the basin's tectonic transition from syn-rift to post-rift conditions.Furthermore, the investigation revealed the presence of Vendotaenia macroalgae, a diagnostic late Ediacaran index fossil, within shale horizons of the Tabia member's third sedimentary sequence (DS3). Integrated with regional chemostratigraphic correlations, this study precisely constrained the base of Cambrian (the BACE - Basal Cambrian Carbon Isotope Excursion) to a position approximately 50 meters above the Tamjout Dolomite (Figure 5). This defined boundary exhibits remarkable concordance with the basin's major tectonic transition surface. The study demonstrates that the BACE negative carbon isotope excursion represents a globally synchronous chronostratigraphic marker, thereby establishing a robust standard for identifying the Ediacaran-Cambrian boundary not only in the Anti-Atlas but also in coeval sedimentary basins worldwide.The research was supported by the National Key Research and Development Program of China and the National Natural Science Foundation of China.Reference: Yiwei Xiong, Bo Chen*, Xiaojuan Sun, Kai Chen, Ibtissam Chraiki, Aihua Yang, Chunlin Hu, Zhixin Sun, Bing Pan, Chuan Yang, Tianchen He, Miao Lu, Tao Li, Fangchen Zhao, Maoyan Zhu, El Hafid Bouougri. 2025. Integrated analyses of the Ediacaran-Cambrian boundary sequence in northern Gondwana (Anti-Atlas platform, Morocco). Gondwana Research 145: 79–106. https://doi.org/10.1016/j.gr.2025.05.003.Figure 1 Simplified map along the northern margin of West African Craton (WAC) showing the occurrence of the Late Ediacaran-Cambrian strata in the Anti-Atlas and composite δ13Ccarb profile of the Ediacaran-Lower Cambrian sequence in the Anti-AtlasFigure 2 Paleogeography and tectono-sedimentary evolution across the Ediacaran-Cambrian transition Synrift stage 1 (DS1): The rift initiationSynrift stage 2, (DS 2): Faults reactivated and rift propagation, Synrift stage 3 (DS3): Continued basin growth, tectonic subsidence and marine transgression, Postrift stage: Stable carbonate platform and thermal subsidenceFigure 3 Boxplot for comparing all data-features of the Dolomite type 1 and Dolomite type 2.Figure 4 Interpretative geological sectionshowing the conceptual model for the formation mechanism of the Dolomite type 1 (a) and Dolomite type 2 (b) (not to scale)Figure 5 Carbon isotope chemostratigraphic and biostratigraphic correlation between the Tabia, Oued Sdass, Oued N’Oulili and Zaouia sections in Anti-Atlas platform

2025-06-17

First Discovery of Silurian Gastropod Pterotheca in China

Pterotheca Salter, 1853 is a morphologically highly unusual gastropod genus widely distributed in the Upper Ordovician and Llandovery Series (Lower Silurian) of North America and Europe. Its distinctive morphological features, including a bilaterally symmetrical shell shape, flattened shell, and a unique internal triangular septum, initially led to taxonomic confusion among early researchers, who misidentified it as a brachiopod, hyolith, pteropod, or cephalopod (operculum). Due to its highly specialized shell structure and striking morphology, which make it easily recognizable, the phylogenetic characteristics and paleoecological patterns of Pterotheca have long been a research focus in paleontology. However, as its fossil record has so far only been found in Europe and North America, with no reports from other regions, there remains controversy within the academic community regarding its paleogeographic distribution pattern.Recently, Assistant Researcher Li Wenjie from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, collaborating with multiple team members, discovered Pterotheca fossils for the first time in the Xiushan Formation (mid-Telychian, Llandovery Epoch) of Yongshun County, Hunan Province, China. This discovery represents the first record of the genus in the low-latitude peri-Gondwanan region. Based on these new specimens from the South China Block, researchers identified two new species according to the morphological characteristics of the Pterotheca fossils: Pterotheca yongshunensis n. sp. and Pterotheca xiushanensis n. sp. The morphologic analysis suggests that close relatives of these new species may be Pterotheca species from the Telychian of Scotland. The new species show continuous variations of marginal apex to submarginal apex, implying that one of the Pterotheca species may be ancestral to the Devonian Aspidotheca Spriesterbach, 1919.Sedimentological and paleoecological analyses suggest that the Pterotheca species from the Silurian of South China likely lived on soft silt-mud substrates, crawling slowly and feeding on algae and/or organic detritus within the sediment. They were adapted to shallow marine environments with substantial terrigenous input (Benthic Assemblage 2–3). Given that many localities yielding Silurian Pterotheca fossils (including South China and Spain) lack records of Ordovician Pterotheca, and considering that all known Silurian Pterotheca fossils occur in fine-grained siliciclastic rocks, with most sedimentary features representing periods of sea-level fall and lowstand, it is hypothesized that geographic isolation and enhanced oceanic circulation during the global sea-level fall in the early Silurian promoted speciation of Pterotheca in different regions worldwide. Conversely, the connection of sea routes during the Rhuddanian transgression following the end-Ordovician glaciation may have facilitated the initial dispersal of Silurian Pterotheca.The research findings were recently published in the international paleontological journal Journal of Paleontology. The related research received support from Ministry of Science and Technology and National Natural Science Foundation of China. This study is a contribution to IGCP project 735 “Rocks and the rise of Ordovician life”.Reference: Li, W.J.*, Fang, X., Song, J., Zhang, Y.D., 2024. Pterotheca (Gastropoda) from the Telychian (Silurian) Xiushan Formation of South China: taxonomy, paleoecology, and paleogeography. Journal of Paleontology 98, 981–995. https://doi.org/10.1017/jpa.2024.49.Pterotheca yongshunensis n. sp. from the Xiushan FormationPterotheca xiushanensis n. sp. from the Xiushan Formation

2025-06-09

The Permian Fusuline Fauna in Exotic Limestone Blocks of the Western Yarlung Tsangpo Suture Zone: Insights into the Early Evolution of the Neo-Tethys Ocean

As the youngest ocean within the Tethyan Orogen, the opening time of the Neo-Tethys Ocean has remained a subject of debatewith different opinions such as prior to Middle Permian, Early Triassic, or Late Triassic. Resolving this issue is of great significance for understanding the geodynamic evolution of the Tethyan Orogen. Concurrently, as the remnants of the Neo-Tethys Ocean, the Yarlung Tsangpo Suture Zone (YTSZ) exhibits a complex structural background. In the east of Saga, it is characterized by a single ophiolite zone, but splits into northern and southern subzones west of Sage, with the Zhongba-Zhada microcontinent sandwiching between them. The fundamental question of whether both subzones represent a single suture or distinct sutures representing different oceans has remained a considerable debate.Recent researchers have increasingly focused on abundant exotic limestone blocks preserved in the mélange of the YTSZ. Much attention has been paid on the geochemistry and paleomagnetism of the associated basalt. However, the study on the biostratigraphy and paleobiogeography of these exotic limestone blocks remains scarce, with limited studies in the Gyanyima area, Purang County. With the Second Tibetan Plateau Scientific Expedition and other research funding, a research team lead by Prof. Yichun Zhang conducted fieldworks in 2022 and 2024. The works in the field discovered numerous exotic limestone blocks within the mélanges on both sides of the Zhongba-Zhada microcontinent. The exotic limestone blocks in the southern subzone suffer slight metamorphism, preserving diverse fusuline and coral fossils, but those in the northern subzone were strongly metamorphosed, leaving limited Permian foraminifers.The research team has recently conducted a systematic study on fusulines from the exotic limestone blocks in the Yarlung Tsangpo Suture Zone, focusing on fusuline fossils in the limestone blocks of the southern subzone. The Gyanyima section in Purang County contains a fusuline fauna dominated by Neoschwagerina, Kahlerina, and Yangchienia, with some species of Verbeekina, Chusenella, Colania, and Codonofusiella, indicating a Wordian-Capitanian age. In addition, the Zhalairi area in the south of Zhongba County is characterized by an assemblage rich in Codonofusiella and Lantschichites, accompanied by minor Neoschwagerina, Yangchienia, and Chenella, suggesting a late Capitanian age.Paleobiogeographic analysis reveals that these fusuline assemblages exhibit high abundance but low diversity, conspicuously lacking advanced genera (e.g., Sumatrina, Yabeina, Lepidoliolina). The paleobiogeographic affinities of the faunas indicate that these exotic limestone blocks were formed in a position between the northern Lhasa Block and the southern Indian Plate during the Middle Permian. Additionally, the limestone blocks lack terrigenous clastic but associated with basalt, strongly suggesting an origin of the seamounts in the Neo-Tethys Ocean. It deserves note that the occurrence of warm-water fusuline-containing limestones was in the south of the Zhongba-Zhada microcontinent with typical cold-water faunas. This phenomena strongly supports that the southern subzone was not in situ but originated from the northern subzone. The southern and northern subzones of the YTSZ belong to a same ophiolite belt, both representing the remnants of the Neo-Tethys Ocean.In conclusion, this study confirms that the Neo-Tethys Ocean opened in the late Early Permian, and subsequently developed series of seamounts in the ocean basin by the Middle Permian. During the collision between India and Eurasia, the ophiolites obducted and transported the mélange and limestone blocks to form the southern subzone. Those limestone blocks within the northern subzone, however, suffered from strong metamorphism. This study provides significant evidence in understanding the early evolution of the Neo-Tethys Ocean and the tectonic affinity of the subzones of the YTSZ.This research was supported by the Second Tibetan Plateau Scientific Expedition and the National Science Foundation of China.Reference: Hong-fu Zhou, Yi-chun Zhang*, Mao Luo, Xin Li, Hua Zhang, Hai-peng Xu, Ruo-lan Liao, Qi Ju, Xiao-Hui Cui, Jun-jie Liu, Yao-feng Cai, Shu-zhong Shen, 2025. Dismembered Guadalupian (Middle Permian) seamounts within the Yarlung-Tsangpo Suture Zone: Implications for the opening time of the Neo-Tethys Ocean. Palaeogeography, Palaeoclimatology, Palaeoecology, 675:113063. https://doi.org/10.1016/j.palaeo.2025.113063.The exotic limestone in the ophiolite mélange of the Yarlung-Tsangpo Suture Zone. (A, Full view of the exotic limestone blocks in the Zhalairi area; B, The exotic limestone in the ZLR1 section; C, The exotic limestone in the ZLR3 section; D, The Bijiula section; E, The exotic limestone in the JYM2 section; F, The interlayered basalts in the JYM2 section.)The cartoon showing the formation of the seamounts within the Neo-Tethys Ocean and its obduction to the south of the Zhongba-Zhada microcontinent during the collision between the Tethys Himalaya Terrane and the Lhasa Block

2025-06-04

Chinese scientists reported the the earliest known fossil record of blue-stain fungus

In a recent report published in National Science Review, a Chinese team of scientists highlights the discovery of well-preserved blue-stain fungal hyphae within a Jurassic fossil wood from northeastern China, which pushes back the earliest known fossil record of this fungal group by approximately 80 million years. The new finding provides crucial fossil evidence for studying the origin and early evolution of blue-stain fungi and offers fresh insights into understanding the ecological relationships between the blue-stain fungi, plants, and insects during the Jurassic period.Blue-stain fungi constitute a distinctive group of wood-colonizing fungi which lack the ability to decompose wood lignocellulose, yet are capable of causing significant wood discoloration. Though these fungi are generally nonfatal to their hosts, they often accelerate tree mortality when associated with wood-boring insects.Molecular phylogenetic analyses suggest that blue-stain fungi should be an old fungal group, which might originate during the Late Paleozoic or early Mesozoic. However, hardly anything is known about the geological occurrences of blue-stain fungi.Not until 2022, the first credible fossil record of blue-stain fungi was reported from the Cretaceous in South Africa with an age of approximately 80 million years.This research team was led by Prof. Ning Tian from Shenyang Normal University (SNU) and Prof. Yongdong Wang from Nanjing Institute of Geology and Palaenology, CAS (NIGPAS), and was jointly studied by Prof. Zikun Jiang from the Chinese Academy of Geological Sciences in Beijing as well as other scholars from SNU. They foundwell-preserved fossil fungal hyphae preserved within a Jurassic petrified wood from northeastern China, dated 160 million years ago. Microscopic examination reveals thefossil hyphae are dark in colour, which is indicative of pigmentation, a hallmark of contemporary blue-stain fungi which results in the discoloration of woods. Of interest, when penetrating the wood cell wall, the hyphae commonly form a very specialized structure called “penetration peg”. That is to say when pushing through the wood's cell walls, the hyphae commonly slim down in size, making it easier to pierce through the tough barrier. The discovery of the penetration peg enables the team to ensure that the fossil fungus that they found belongs to the blue-stain fungi. Unlike wood-decay fungi, which degrade wood cell walls through enzymatic secretion, the blue-stain fungi lack the enzymatic capacity to decompose wood structures. Instead, their hyphae mechanically breach wood cell walls via the penetration pegs.The finding of Jurassic blue-stain fungi from China pushes back the earliest known fossil record of this fungal group by approximately 80 million years, providing crucial fossil evidence for further understanding the origin and early evolution of blue-stain fungi.Additionally, it offers fresh insights into understanding the ecological relationships between the blue-stain fungi, plants, and insects during the Jurassic period. The bark beetle subfamily Scolytinae is considered as one of the major spore dispersal agents for extant blue-stain. However, both molecular biological and fossil evidence proposed that the origin time of Scolytinae dates back no earlier than the Early Cretaceous. Given the Jurassic age of present fossil fungus, it is hypothesized that its spore dispersal vector was not Scolytinae but rather other wood-colonizing insects prevalent during that period.This study was funded by the National Natural Science Foundation of China and the Liaoning Revitalization Talents Program.Article information:Tian Ning*, Wang Yongdong*, Li Fangyu, Jiang Zikun, Tan Xiao, 2025. Blue-stain fungus from the Jurassic provides new insights into early evolution and ecological interactions. National Science Review, 12(6): nwaf160. https://doi.org/10.1093/nsr/nwaf160.Figure 1 Anatomical details of the fungus-bearing wood Xenoxylon phyllocladoides Gothan from the Jurassic of western Liaoning, NE China(a) Transverse section, a insect-boring hole. (b, c) Transverse section, distinct growth rings with collapsed early wood. (d-e) Radial section, uniseriate distant bordered pits. (f, g) Radial section, window-like cross-field pits. Bars: (a) 500 μm; (b) 200 μm; (c) 100 μm; (d-g) 50 μm.Figure 2. Blue-stain fungus in wood tissues of Xenoxylon phyllocladoides Gothan from the Jurassic of western Liaoning Province, NE China.(a–c) Hyphae with septa (white arrow heads). (d) Hyphae growing in the cross-field zone. (e, h) Hyphae penetrating tracheid walls with appressorium-like structures and distinct hyphal pegs (white arrow heads). (f) Colonization of ray parenchyma cells by hyphae. (g, i–j, l) Hyphae horizontally penetrating the tracheid walls with appressorium-like structures. (k) Hyphae colonizing in the tracheid lumen, and passing through the bordered pits. (m–o) Slender hyphae within tracheid lumen with chlamydosporelike structures (white arrow heads).Bars: (a–d, f–n) 50 μm; (e) 25 μm.

2025-05-30