Recently, a research team focusing on the Late Paleozoic at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS)—consisting of Associate Professor ZHENG Quanfeng, Professor WANG Yue, Assistant Professor HUANG Xing, and Professor CHEN Bo—collaborated with Nanjing Normal University, China University of Mining and Technology, and Nanjing University to conduct a high-resolution sedimentological, fusuline biostratigraphic, and inorganic carbon isotope stratigraphic study of the Chuanshan–Chihsia formations at the Kongshan section in Nanjing. Based on regional and global correlations, this team reconstructed a high-resolution glacioeustatic sea-level curve spanning the Asselian to middle Kungurian stages, thereby elucidating the evolution of the Late Paleozoic Ice Age (LPIA) during the early Permian.Recently, a research team focusing on the Late Paleozoic at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS)—consisting of Associate Professor ZHENG Quanfeng, Professor WANG Yue, Assistant Professor HUANG Xing, and Professor CHEN Bo—collaborated with Nanjing Normal University, China University of Mining and Technology, and Nanjing University to conduct a high-resolution sedimentological, fusuline biostratigraphic, and inorganic carbon isotope stratigraphic study of the Chuanshan–Chihsia formations at the Kongshan section in Nanjing. Based on regional and global correlations, this team reconstructed a high-resolution glacioeustatic sea-level curve spanning the Asselian to middle Kungurian stages, thereby elucidating the evolution of the Late Paleozoic Ice Age (LPIA) during the early Permian.This study has been published in the international journal Palaeogeography, Palaeoclimatology, Palaeoecology.Since the beginning of the Phanerozoic Eon, Earth has experienced four major icehouse periods: the end-Ordovician, Late Devonian, Late Paleozoic, and Cenozoic ice ages. Among them, the LPIA was the most extensive and long-lasting, profoundly influencing environmental and biological evolution on Earth. However, its termination age has long been debated, with proposed timings ranging from the mid-Sakmarian to the Artinskian, late Guadalupian, and even late Lopingian.During major icehouse intervals, large volumes of surface water are stored in continental or alpine glaciers at high latitudes or altitudes, thereby reducing global seawater volume and maintaining sea level at a long-term low stand. At the same time, Milankovitch orbital cycles drive alternating cold and warm phases, causing periodic glacier advance and retreat and resulting in high-frequency, globally synchronous sea-level fluctuations. These long- and short-term changes in sea level, known as glacioeustasy, provide a key geological indicator for reconstructing the onset, evolution, and disappearance of ancient ice ages.The study shows that the Chuanshan Formation (Asselian to early Artinskian) was deposited in a shallow-water carbonate shoreface environment, whereas the overlying Chihsia Formation (middle–late Artinskian to middle Kungurian) formed in a deep-water carbonate shelf setting. This lithofacies transition records a rapid and significant transgression during the middle–late Artinskian.Detailed sedimentological analysis reveals that the Chuanshan Formation is characterized by numerous meter-scale depositional cycles, each comprising lower subtidal deposits and upper subaerial-exposure or intertidal deposits, indicating prominent high-frequency sea-level oscillations. However, these cycles abruptly disappear in the Liangshan Member of the basal Chihsia Formation. Up-section, the Chihsia Limestone becomes uniformly composed of deep-shelf bioclastic limestones, reflecting a marked weakening—and eventual disappearance—of high-frequency sea-level fluctuations.Inorganic carbon isotope values correlate closely with lithofacies: intertidal or subaerial exposure facies typically yield δ¹³C values below 1‰, whereas subtidal deposits generally exceed 2‰. These patterns suggest that isotopic variations were mainly controlled by the relative influence of meteoric and marine diagenesis, making them a reliable proxy for relative sea-level changes.Regional and global correlations indicate that both the high-frequency sea-level fluctuations from the Asselian to early Artinskian and the major transgression in the middle–late Artinskian are globally recognizable phenomena. The 19 high-frequency cycles identified in the Asselian-Sakmarian Chuanshan Formation have an average periodicity of ~463 kyr, closely matching the long-eccentricity Milankovitch cycle, supporting an orbital forcing origin for these fluctuations.Taken together, the relative sea-level changes recorded in the Chuanshan–lower Chihsia formations at Kongshan can be confidently interpreted as glacioeustatic signals driven by the waxing and waning of continental ice sheets. This allows reconstruction of the LPIA evolution during the early Permian, including: (1) an ice maximum during the Asselian–early Sakmarian; (2) a brief warming during the mid-Sakmarian; (3) a final ice maximum from the late Sakmarian to early Artinskian; and (4) a rapid, great deglaciation during the middle–late Artinskian.The middle–late Artinskian deglaciation effectively marks the termination of the Late Paleozoic Ice Age, during which continental ice sheets nearly completely disappeared, with only limited alpine glaciers persisting into the late Permian.This study provides the first high-resolution, multi-scale evidence of glacioeustatic sea-level changes from South China, delineating the complete transition of the LPIA from peak glaciation to final demise, offering crucial geological insights into Earth's late Paleozoic climate evolution.This research was supported by the National Natural Science Foundation of China.Reference: Zheng, Q.F.*, Wang, Y.*, Huang, X, Chen, B, Wu, H.P., Yuan, D.X., Wang, X.D., Shen, S.Z., 2025. Artinskian great deglaciation: Glacioeustasy evidence from South China. Palaeogeography, Palaeoclimatology, Palaeoecology, 679: 113310. https://doi.org/10.1016/j.palaeo.2025.113310.Fig. 1 Outcrop photograph of the upper Chuanshan Formation showing meter-scale cyclic deposits at the Kongshan section in Nanjing (A), and representative images of major lithofacies on polished slab (B) and in thin sections (C–D).Fig. 2 Integrated stratigraphic column of the Kongshan section in Nanjing, showing chronostratigraphy, lithostratigraphy, lithofacies associations (LFA), sedimentary environments (Sed. Env.), sedimentological log, inorganic carbon isotopes, and relative sea-level changes.Fig. 3 Comparison of sea-level changes, relative global continental ice-volume variations, glacial history, and atmospheric CO₂ partial pressure during the Asselian to middle Kungurian stages of the Cisuralian Series (Early Permian).
A recent study by Assistant Professor CHENG Cheng and Professor ZHANG Hua from the Late Paleozoic research team at the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS), in collaboration with researchers from Nantong University, Hefei University of Technology, and Nanjing University, has been published in Palaeogeography, Palaeoclimatology, Palaeoecology. The work deciphers how pulsed volcanism in the Emeishan Large Igneous Province (ELIP) triggered the collapse of the Late Paleozoic Ice Age (LPIA) during the Guadalupian–Lopingian (G–L) transition through disruptions in the global carbon cycle.A recent study by Assistant Professor CHENG Cheng and Professor ZHANG Hua from the Late Paleozoic research team at the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS), in collaboration with researchers from Nantong University, Hefei University of Technology, and Nanjing University, has been published in Palaeogeography, Palaeoclimatology, Palaeoecology. The work deciphers how pulsed volcanism in the Emeishan Large Igneous Province (ELIP) triggered the collapse of the Late Paleozoic Ice Age (LPIA) during the Guadalupian–Lopingian (G–L) transition through disruptions in the global carbon cycle.The Late Paleozoic Ice Age (LPIA) was the longest-lasting icehouse climate of the Phanerozoic, and its transition to a greenhouse state represents a critical turning point in Earth's climate evolution. The Guadalupian–Lopingian (G–L) transition, marking the final stage of the LPIA, records key evidence of deglaciation and perturbations in the global carbon cycle. Although the Emeishan Large Igneous Province (ELIP) has been proposed as a potential trigger for this transition, the mechanistic linkages between volcanism and deglaciation had remained inadequately understood.The research team conducted high-resolution integrated geochemical analyses of carbonate-dominated strata from the Xikou section in Zhen’an, South Qinling, including mercury geochemistry, paired carbonate and organic carbon isotopes (δ13Ccarb, δ13Corg), redox-sensitive trace elements (e.g., MoEF), and chemical weathering indices (e.g., chemical index of alteration, CIA). The results reveal five distinct volcanic pulses during the Capitanian to Wuchiapingian stages, each showing synchronous correspondence with negative carbon isotope excursions, elevated chemical weathering indices, and enrichments in redox-sensitive elements (Fig. 1).This coupled volcanic-climatic-oceanic pattern demonstrates that ELIP eruptions released massive amounts of 13C-depleted CO2, triggering recurrent warming episodes that progressively destabilized the P4 glaciation and led to ice-sheet collapse. Notably, this pattern can be extended to the global deglaciation of the LPIA, where eruptions from the Tarim II (ca. 290 Ma), Tarim III (ca. 280 Ma), and Emeishan (ca. 260 Ma) large igneous provinces uniformly triggered interglacial phases (Fig. 2).Additionally, an early Wuchiapingian +1.4 ‰ shift in Δ13C (δ13Ccarb -δ13Corg) indicates enhanced organic carbon burial under declining volcanic activity, which contributed to the atmospheric oxygenation and facilitated ecosystem recovery- processes that in turn supported post-eruptive climatic cooling.By correlating volcanic activity with climate proxies from a single section, this study establishes pulsed volcanism as a principal driver of icehouse-greenhouse transitions. The findings offer critical insights into carbon-cycle–climate feedbacks, with direct relevance to understanding modern global warming dynamics.This study was supported by the National Natural Science Foundation of China, the Nanjing Institute of Geology and Palaeontology (Chinese Academy of Sciences), and the Jiangsu Provincial Department of Education.Reference: Cheng Cheng*, Hua Zhang*, Dan Wang, Shuangying Li, Shuzhong Shen. Pulsed volcanism in the Emeishan Large Igneous Province drove deglaciation during the Guadalupian-Lopingian transition. Palaeogeography, Palaeoclimatology, Palaeoecology, 2025, 679, 113302. https://doi.org/10.1016/j.palaeo.2025.113302.Fig. 1 Geochemical and isotopic records from the Xikou section spanning the Capitanian to Wuchiapingian stagesFig. 2 Correlation among Permian glaciations from eastern Australia, Large Igneous Provinces, biodiversity changes, and anoxic events
In a new study published in Earth and Planetary Science Letters, a joint research team led by Dr. LIU Qian and Dr. LI Tao from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and Dr. CHEN Sang from Shanghai Jiao Tong University, has resolved these uncertainties. Collaborating with researchers from the University of Bristol and Nanjing University, the team successfully identified the primary non-environmental controls on Li/Mg fractionation.In a new study published in Earth and Planetary Science Letters, a joint research team led by Dr. LIU Qian and Dr. LI Tao from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and Dr. CHEN Sang from Shanghai Jiao Tong University, has resolved these uncertainties. Collaborating with researchers from the University of Bristol and Nanjing University, the team successfully identified the primary non-environmental controls on Li/Mg fractionation.Deep-sea scleractinian corals serve as critical "natural archives," preserving high-resolution geochemical records of long-term oceanographic changes. Among emerging proxies, the Lithium-to-Magnesium ratio (Li/Mg) in coral skeletons has gained traction as a potential paleothermometer. However, its reliability has been hindered by unexplained variability across different skeletal structures and an incomplete understanding of the underlying biomineralization mechanisms.To isolate the drivers of geochemical variability, the researchers conducted a systematic analysis of 60 modern branching cold-water coral specimens collected from the North Atlantic, Equatorial Atlantic, and Eastern Equatorial Pacific. They performed comparative sampling of two distinct skeletal structures: the corallites (cup skeletons) and the branches (coenosteum). The results revealed a significant and systematic offset that trace element ratios such as Li/Ca, Mg/Ca, B/Ca, and notably Li/Mg, were consistently enriched in the corallites compared to the branches. Conversely, Sr/Ca and U/Ca ratios showed the opposite trend. After excluding the influence of Centers of Calcification (COC), the modeling results combined with existing inorganic precipitation experiments identified skeletal growth rate as the dominant factor controlling the Li/Mg offset between the two structures.This study has immediate implications for paleoceanography. The authors advocate for a standardized sampling protocol that strictly differentiates between skeletal structures, specifically separating corallites from branches, to eliminate systematic errors caused by growth rate variations. Furthermore, the study highlights the necessity of incorporating biomineralization mechanisms into future Li/Mg temperature calibrations to minimize proxy uncertainty.This work was supported by the National Key Research and Development Program of China and the National Natural Science Foundation of China.Reference: Liu, Q., Stewart, J.A., Robinson, L.F., Chen, S.*, Wang, M., Chen, T., Li, T.*, 2026. Colonial cold-water coral Li/Mg palaeothermometry: Influence of growth rate and skeletal heterogeneity. Earth Planet. Sci. Lett. 674, 119743. https://doi.org/10.1016/j.epsl.2025.119743.Fig.1 Colonial cold-water coral collection map and the subsampling strategyFig.2 The elemental ratios of corallite and Branch and their relationship with temperatureFig.3 The SEM photos of (a) corallite and (b) branch with (c) the influence of growth rate on Li/Mg ratio
Recently, a new high-resolution biomarker study of the Zal section in NW Iran (Fig. 1), was conducted by Ph.D. student JIAO Shenglin, his advisor Prof. ZHANG Hua from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and an international team. This study systematically reveals ecological disturbance and microbial community dynamics across the P–T transition in Northwest Iran.Recently, a new high-resolution biomarker study of the Zal section in NW Iran (Fig. 1), was conducted by Ph.D. student JIAO Shenglin, his advisor Prof. ZHANG Hua from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and an international team. This study systematically reveals ecological disturbance and microbial community dynamics across the P–T transition in Northwest Iran.The study is published in the international journal Palaeogeography, Palaeoclimatology, Palaeoecology.The Permian–Triassic (P–T) transition witnessed the most severe biocrisis in the Phanerozoic, yet microbial community dynamics across this interval remain poorly constrained in key regions of the Paleotethys. The well-preserved, continuous marine records from Iran (western Paleo-Tethys) provide a critical archive of this event. Comparative studies between the western (Iran) and eastern (South China) Paleo-Tethys are essential for a holistic understanding of environmental and biological dynamics, though many questions about Iran's specific environmental and microbial records remain.Research reveals the simultaneous emergence of a triple environmental crisis: First, biomarkers point to a major shift in primary producers—from eukaryotic green and red algae toward bacteria—with cyanobacteria becoming dominant at the extinction horizon. Second, the sediment record captures recurring bottom water anoxia, strong water-column stratification, and sustained intervals of euxinic conditions. Third, marked increases in terrestrial organic matter, likely linked to wildfire activity and soil erosion, indicate that land-derived nutrients may have intensified marine eutrophication (Fig. 2).Notably, these biomarker patterns align with negative δ13C shifts and match trends reported from South China (Fig. 3), suggesting that ecological decline occurred synchronously across the Paleotethys. Collectively, the results point to volcanism-driven environmental collapse on land and widespread marine anoxia as key factors that magnified the end-Permian biocrisis (Fig. 4).This work is supported by the National Key Research and Development Program of China and the Jiangsu Innovation Support Plan for International Science and Technology Cooperation Program.Reference: Jiao, S.L., Zhang, H.*, Arefifard, S., Cai, Y.F., Gorgij, M.N., Liu, X.Y., Ni, W., Tang, L.K., Cao, J., Shen, S.Z., 2026. Ecological disturbance and microbial community dynamics across the Permian–Triassic transition in Northwest Iran. Palaeogeogr. Palaeoclimatol. Palaeoecol. 682, 113432. https://doi.org/10.1016/j.palaeo.2025.113432.Fig.1 Chromatogram of the saturated and aromatic fractions of selected samples of the Zal sectionFig.2 High-resolution chemostratigraphy of the Zal section through the P–T transition.Fig.3 Comparison of the geochemical records during the P–T transition between the Zal section in Northwest Iran and the Meishan and Shangsi sections in South China.Fig.4 Conceptual models of oceanic anoxia and ecological disturbance in terrestrial–marine systems from the late Permian to Early Triassic.
Recently, YE Kai, a Master’s student at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), under the joint guidance of Associate Porfessor GUO Wen (NIGPAS) and Associate Porfessor RAO Xin (Northwest University), collaborated with Prof. WANG Ming (Jilin University), Prof. Peter W. Skelton (The Open University, UK), and other researchers, reports the first record of Early Aptian (late Early Cretaceous) radiolitid rudist bivalves—Agriopleura libanica (Astre)—from the Langshan Formation in the Nima Basin, northern Lhasa Terrane. This taxon represents the oldest rudist fossil record currently known in China. The relevant research findings have been published in the international journal Palaeoworld.The Late Jurassic–Cretaceous Hippuritida Newell, 1965 (rudist bivalves) was sessile, epifaunal organisms that abundantly colonized the tropical and subtropical shallow carbonate platform tops and gentle slopes. Their rapid evolution and extensive geographic distribution make rudists particularly valuable for Cretaceous biostratigraphic correlations and paleoenvironmental reconstructions. The Langshan Formation, extensively distributed in the northern Lhasa Terrane of the Tibetan Plateau, has long been considered to have been deposited from the Late Aptian to the Early Cenomanian. However, convincing sedimentary or paleontological evidence for the Early Aptian interval has remained notably scarce.Recently, YE Kai, a Master’s student at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), under the joint guidance of Associate Porfessor GUO Wen (NIGPAS) and Associate Porfessor RAO Xin (Northwest University), collaborated with Prof. WANG Ming (Jilin University), Prof. Peter W. Skelton (The Open University, UK), and other researchers, reports the first record of Early Aptian (late Early Cretaceous) radiolitid rudist bivalves—Agriopleura libanica (Astre)—from the Langshan Formation in the Nima Basin, northern Lhasa Terrane. This taxon represents the oldest rudist fossil record currently known in China. The relevant research findings have been published in the international journal Palaeoworld.This team collected well-preserved right-valve specimens of Agriopleura libanica, together with associated Offneria murgensis fossils, from the limestones of the Langshan Formation in the Zhongcang area of Nima County. The comparison between Ag. libanica and Auroradiolites supports the hypothesis that Auroradiolites descended directly from Ag. libanica, as evidenced by shared ligamentary, dental and myophoral structures.The Agriopleura libanica–Offneria murgensis assemblage is an index of the lower Aptian of the southern Tethyan Arabian–African margin. The discovery of this assemblage in the Lhasa Terrane confirms the presence of a carbonate seaway in the Nyima region during the early Aptian (late Early Cretaceous), highlighting the significance of the Langshan Formation for reconstructing the paleogeography of northern Lhasa Terrane and the evolution of the Bangong-Nujiang Ocean. The occurrence of A. libanica in the Lhasa Terrane fills a critical geographic gap, bridging its known distribution from Arabia to East Asia during the early Aptian. It represents the first record of this species on the northern margin of the Tethys, as well as the first documentation of early Aptian rudists along the northern margin of the eastern Tethyan Ocean. These discoveries challenge the traditional division between northern and southern Tethyan rudist provinces, demonstrating cross-Tethyan faunal connectivity during the early Aptian.This study is financially supported by the National Natural Science Foundation of China, the Second Tibetan Plateau Scientific Expedition and Research Program, the Scientific Research Project of the Education Department of Jilin Province, and the State Key Laboratory of Palaeobiology and Stratigraphy.Reference: Kai Ye, Xin Rao*, Quewang Danzeng, Peter W. Skelton, Bintao Gao, Yiwei Xu, Ting Ruan, Kun Liang, Wen Guo, Ming Wang*. First record of early Aptian (Early Cretaceous) radiolitid Agriopleura libanica (Astre) from the Langshan Formation, northern Lhasa Terrane: Oldest rudist bivalves in China. Palaeoworld. https://doi.org/10.1016/j.palwor.2025.201054.Fig. 1 (A) Tectonic framework of the Qinghai-Xizang (Tibet) Plateau (modified from Li et al., 2006) and (B) simplified geological map of research area in the Zhongcang region (modified from Xie and Zou, 2002).Fig. 2 Agriopleura libanica (Astre) from NyimaFig. 3 Chronostratigraphic ranges of Cretaceous rudists in the Langshan Formation, Lhasa TerraneFig. 4 Paleogeographic distribution of early Aptian Agriopleura libanica.
A collaborative study by the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), Lee Kong Chian Natural History Museum (Singapore), and Chengdu University of Technology provides new insights into this question. The findings were published in Royal Society Open Science, with Associate Professor LUO Cui from NIGPAS as the first and corresponding author.Porifera represents one of the most basic metazoan lineages, distributed in a wide range of environmental settings since the early Cambrian. Previous studies have established that their ecological success can be attributed to (i) optimized morphologies and anchoring structures adapted to varying hydrodynamic and substrate conditions, and (ii) phenotypic plasticity. Many extant sponges modulate shapes, positions of oscula, spicule density, anchoring strategies, and so on, in response to environmental changes. Have these strategies remained almost unchanged since the early Cambrian, or have they been progressively shaped and refined over geological time?A collaborative study by the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), Lee Kong Chian Natural History Museum (Singapore), and Chengdu University of Technology provides new insights into this question. The findings were published in Royal Society Open Science, with Associate Professor LUO Cui from NIGPAS as the first and corresponding author.The studied Lotispongia helicolumna gen. et sp. nov. was collected from the Wulongqing Formation (Cambrian Stage 4), Yunnan Province. It belongs to the family Leptomitidae, which encompasses common Cambrian inhabitants of siliciclastic soft substrates but demised after the Ordovician. While conforming to leptomitid diagnostic characteristics, L. helicolumna exhibits a sophisticated set of features unprecedented in this family: (1) a robust body wall woven by spirally twisted monaxonic spicules; (2) a thick stub-like root tuft for anchoring; (3) spicules radiating out from the sponge body to prevent clogging and sinking; and (4) the inferred capability to close the osculum against unfavourable stimuli. Among these features, the spirally twisted monaxons are reminescent of the Cambrian fossil Kiwetinokia, but their presence in L. helicolumna likely represents an independent origin. Features (2) and (3) are common in extant soft-substrate sponges but unprecedented among Cambrian leptomitids. Feature (iv) is also common in modern sponges responding to adverse stimuli, but has not been documented in fossils.These observations indicate that L. helicolumna had evolved some adaptive strategies comparable to extant sponges. However, morphometric analysis of 19 well-preserved specimens (out of the 78 collected specimens) reveals strictly similar lotus-bud-like morphologies regardless of size. This indicates that L. helicolumna lacked the morphological plasticity and modular aquiferous systems that endow the ecological success of modern sponges.This unique case suggests that Cambrian leptomitid sponges may have significant differences from modern sponges in physiology. Although complex adaptive features could be achieved upon this ancient physiology, the absence of morphological plasticity may have ultimately constrained the persistence of these ancient sponge groups. This study offers novel perspectives for future investigation of early sponge evolutionary patterns and mechanisms.This study was supported by the National Natural Science Foundation of China.Reference: Luo, C., Hong, Y., Sun, Z., Sun, H., Lim, S.C., Wang, T., Zhang, L., and Zhao, F., 2025, Advanced adaptive strategies in an ancestral body plan: insights from a 510-Ma-old leptomitid sponge: Royal Society Open Science, v. 12, p. 251072, https://doi.org/10.1098/rsos.251072.Fig. 1 The holotype (A, E, F) and a paratype (B, G, H–I) of L. helicolumna, and the thin sections cutting through a L. helicolumnaspecimen (C) and its host rock (D).Fig. 2 A few paratypes of L. helicolumna, showing its morphological details.Fig. 3 Morphometric analysis of L. helicolumna based on 19 specimens.Fig. 4 Endopsammic demosponge Spheciospongia sp. from Singapore, with the oscula closed (A) and open (B).
Recently, a detailed study on high-resolution carbonate δ15N (Fig. 1) is conducted on the well-preserved Pennsylvanian carbonate slope- to basinal successions from the South China Block by the Ph.D. student YANG Wenli, her advisor Prof. CHEN Jitao, and their colleagues.The global warming event across the Kasimovian-Gzhelian boundary (KGB) in the late Pennsylvanian was marked by prominent perturbations of global biogeochemical cycles, accompanied by abrupt global warming, widespread marine anoxia, and a distinct biodiversity loss. However, the evolution of marine primary productivity and redox conditions during this short-lived warming event has not yet been explored from the perspective of marine nitrogen cycle. Nitrogen (N) plays a crucial role in regulating marine primary productivity and is highly sensitive to marine redox variations, which thus has the potential for tracking oceanic changes during climatic transitions.The KGB warming and anoxic event thus provides a unique opportunity to investigate how the oceanic nitrogen cycle responded to transient global warming and marine anoxia under long-term icehouse conditions. Recently, a detailed study on high-resolution carbonate δ15N (Fig. 1) is conducted on the well-preserved Pennsylvanian carbonate slope- to basinal successions from the South China Block by the Ph.D. student YANG Wenli, her advisor Prof. CHEN Jitao, and their colleagues.High-resolution sedimentary δ15N, δ13Corg, and δ13Ccarb records were reported from the Luodian Basin, South China during the KGB warming event of the LPIA. The perturbations of δ15N recorded in the three study sections indicate the changes in the nitrogen cycle and redox environments during the KGB warming event. The decrease of δ15N in phase Ⅰ indicates the decreased rate of water-column denitrification. The increase of δ15N in phase Ⅱ indicates the dominance of incomplete denitrification caused by the preliminary enhancement of oxygen depletion due to increase of SSTs. The dramatic negative δ15N excursion (by ~7‰) in phase Ⅲ immediately below the KGB coincides with the previously reported negative shift in δ13Corg, δ13Ccarb, and δ238U, and continued increase in atmospheric pCO2 and SSTs (Fig. 2) suggesting the potential linkage among these proxies. The pronounced negative shift in δ15N most likely resulted from enhanced nitrogen fixation, which was promoted by increased nitrogen loss due to denitrification during the warming-associated marine anoxia (Fig. 3). This paper demonstrates the response of the marine nitrogen cycle to the warming episodes in the icehouse climate and provides a reference case for the future study of the ocean nitrogen cycle in an interglacial climate.The study is published in the international journal Global and Planetary Change.The study is supported by the National Natural Science Foundation of China.Reference: Wenli Yang, Jitao Chen*, Chaosheng Yue, Junpeng Zhang, Yuping Qi, Xiang-dong Wang, Shu-zhong Shen, Enhanced nitrogen fixation as a result of short-lived global warming and marine anoxia in the Late Pennsylvanian icehouse climate, Global and Planetary Change, 2025, 105134, https://doi.org/10.1016/j.gloplacha.2025.105134Fig.1 Correlation of δ15N, δ13Corg, and δ13Ccarb records from the three study sections.Fig.2 Compilation of the Kasimovian-Gzhelian boundary (KGB) warming event.Fig.3 Conceptual diagram of the oceanic nitrogen cycle during the KGB warming event at the Luodian Basin.
Research Professor CHEN Zhe and PhD student LIU Yarong from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS), has made progress in studying the Shibantan Biota in Yichang, Hubei Province, uncovering the oldest known complex three-dimensional burrow systems to date. Preserved in approximately 550-million-year-old strata, these trace fossils show that complex animal behaviors were modifying the seafloor environment nearly 10 million years earlier than previously thought.Research Professor CHEN Zhe and PhD student LIU Yarong from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS), has made progress in studying the Shibantan Biota in Yichang, Hubei Province, uncovering the oldest known complex three-dimensional burrow systems to date. Preserved in approximately 550-million-year-old strata, these trace fossils show that complex animal behaviors were modifying the seafloor environment nearly 10 million years earlier than previously thought.The Ediacaran–Cambrian transition, around 539 million years ago, marks one of the most significant ecosystem revolutions in Earth’s history. A key driver of this ecological shift was the transition of metazoan behavior from simple two-dimensional surface activities to three-dimensional exploration deep into sediments. This “substrate revolution” transformed the seafloor from a uniform, matground-dominated system into a heterogeneously, bioturbated modern-style seabed, permanently altering the trajectory of Earth’s environmental and biological evolution.The researchers conducted a systematic study of trace fossils from the Shibantan Biota (approximately 550–543 million years old). They identified multiple ichnospecies within the genus Treptichnus and established a new ichnospecies, Treptichnus streptosus. By combining these findings with previously discovered three-dimensional trace fossils such as Lamonte and tadpole-shaped traces from the same biota, the study offers an in-depth analysis of the evolutionary and ecological significance of the emergence of animals’ vertical exploration behavior.The findings, published in Science Advances on Oct. 29, reveal that complex animal behaviors emerged on the eve of the Cambrian explosion.Treptichnus is a landmark trace fossil, representing the first “3D exploration” of sediments by animals, and holds importance in evolutionary biology, animal behavior, and ecology. The first appearance of T. pedum, a member of this genus, formally defines the Ediacaran–Cambrian boundary. The new discovery from the Shibantan Biota predates this revolutionary behavior. In addition to reporting the new species T. streptosus, the study identifies other ichnospecies including T. cf. bifurcus, T. rectangularis, and T. pollardi, demonstrating that animal burrowing behaviors had already achieved considerable diversity by this period.Furthermore, the Shibantan Biota preserves other three-dimensional burrows, such as Lamonte and tadpole-shaped traces. The concentrated occurrence of these vertical exploration behaviors reflects early sedimentary ecological stratification and complex foraging strategies, indicating a gradually enhanced ability of trace-making organisms to engineer substrates.The study found that Lamonte caused intensive bioturbation within the Shibantan Biota. This not only disrupted microbial mats on the sediment surface but also dismantled the ecological environment of Ediacara-type organisms that depended on these mats. This suggests bioturbation may have been a contributing factor to the first extinction event of the Ediacara biota around 550 million years ago.The emergence of these complex behaviors and their cumulative ecological effects intensified toward the end of the Ediacaran Period. This led to the gradual decline of microbial mats, continuously eroding the ecological foundation of Ediacara-type organisms while creating new ecological opportunities for the diversification of other metazoans. Driven by the synergy of various biological and non-biological factors, this process ultimately contributed to the profound ecosystem transformation during the Ediacaran–Cambrian transition.This research further confirms that the rich and diverse assemblage of trace fossils and body fossils preserved in the Shibantan Biota provides a window for studying major ecosystem changes at the transition between the Precambrian and Phanerozoic Eons.This work was supported by the National Natural Science Foundation of China.Reference: Zhe Chen* and Yarong Liu, Advent of three-dimensional sediment exploration reveals Ediacaran-Cambrian ecosystem transition, Sci. Adv. 11. https://doi.org/10.1126/sciadv.adx9449.Treptichnus in the Shibantan assemblage in the Wuhe area. Scale bars represent 2 cm.Schematic illustration of trace fossils in the Shibantan assemblage.
Dr. ZHANG Yinggang, a postdoctoral researcher in Research Professor ZHU Maoyan's team at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), in collaboration with Professors Benjamin Mills and Robert Newton (University of Leeds, UK), HE Tianchen (Hohai University), and YANG Tao (Nanjing University), has revealed that long-term orbital variations on million-year timescales may have acted as the “pacemaker” behind these oxygenation pulses. Their findings were recently published in Geophysical Research Letters.Dr. ZHANG Yinggang, a postdoctoral researcher in Research Professor ZHU Maoyan's team at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), in collaboration with Professors Benjamin Mills and Robert Newton (University of Leeds, UK), HE Tianchen (Hohai University), and YANG Tao (Nanjing University), has revealed that long-term orbital variations on million-year timescales may have acted as the “pacemaker” behind these oxygenation pulses. Their findings were recently published in Geophysical Research Letters.The Cambrian Explosion represents one of the most critical milestones in Earth’s evolutionary history, during which nearly all modern animal phyla rapidly emerged. Fossil and geochemical evidence indicate that the early Cambrian diversification of animals occurred in multiple evolutionary pulses, accompanied by synchronous fluctuations in seawater inorganic carbon and sulfate sulfur isotopes. These variations have been interpreted as signatures of periodic oxygenation events in the atmosphere and shallow oceans. However, the driving mechanism behind these rhythmic oxygen pulses has remained elusive.As early as 2019, ZHU’s Sino-British research team conducted a detailed study on well-preserved early Cambrian carbonate successions from the southeastern Siberian Platform. Their results revealed that during the early Cambrian (approximately 524–514 million years ago), marine animal diversity exhibited periodic fluctuations on a timescale of about 2–3 million years, which coincided with excursions in seawater carbon and sulfur isotopes. The team proposed that cyclic changes in the global burial of organic carbon and pyrite led to periodic variations in atmospheric and shallow-marine oxygen levels, thereby influencing the evolutionary dynamics of early marine animals. Following this earlier work published in Nature Geoscience, the team’s latest study further suggests that these million-year-scale environmental oscillations were likely driven by long-period orbital variations. Changes in Earth’s orbital configuration altered the distribution of solar radiation across different latitudes, leading to periodic climate fluctuations. Such climatic changes likely modulated the intensity of continental weathering and the flux of key nutrients, such as phosphorus, into the oceans. The cyclic input of nutrients would have stimulated marine photosynthesis and enhanced organic carbon burial, consequently driving periodic increases in atmospheric and oceanic oxygen levels.To test this hypothesis, the researchers conducted spectral analyses of published early Cambrian carbon-sulfur isotope records, which revealed long-period cycles of 1.2, 2.6, and 4.5 million years, matching the frequencies of known long-term orbital cycles (Figure 1). By incorporating orbitally driven climate forcing into the SCION Earth system box model for the first time (Figure 2), they successfully reproduced the observed synchronous periodic variations in seawater carbon and sulfur isotopes, thereby confirming the plausibility of an orbitally forced oxygenation mechanism (Figure 3). Furthermore, model sensitivity experiments revealed that the low seawater sulfate concentration of the early Cambrian oceans rendered the Earth system particularly unstable, greatly amplifying the response of the coupled carbon–sulfur–oxygen biogeochemical cycles to orbitally modulated nutrient inputs. This finding provides new insights into the pacing of the Cambrian Explosion and offers a broader perspective for understanding long-term carbon, sulfur, and oxygen cycles in other geological intervals.This research was jointly supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China (NSFC), the Jiangsu Funding Program for Excellent Postdoctoral Talent, and the UK Natural Environment Research Council (NERC).Reference: Zhang, Y., Mills, B. J. W., Newton, R. J., He, T., Roper, A., Yang, T., & Zhu, M. (2025). Orbitally-driven nutrient pulses linked to early Cambrian periodic oxygenation and animal radiation. Geophysical Research Letters, 52, e2025GL118689. https://doi.org/10.1029/2025GL118689.Fig.1 Carbonate carbon and carbonate-associated sulfate sulfur isotopes. (a) Records from Cambrian Stage 2 to Stage 4 from the southeastern Siberian Platform. (b) Number of animal species. (c) Wavelet analysis of the carbon isotope record, and (d–e) 384 Kyr and 1.2 Myr filter output from the sulfur isotope record.Fig.2 Orbitally induced climate approximation in the SCION model. (a) Comparison of solar insolation at 65°N with air temperature variations over 40–80°N in the past 1500–2450 kyr. (b) A cross plot of solar insolation at 65°N with the air temperatures. (c) Insolation-induced air temperature 2D deviation stacks in the revised SCION model schematic diagram.Fig.3 SCION model outputs with key parameters varied within 20% uncertainty. (a) shelf nutrient phosphorus reservoir size. (b) anoxic seafloor extent compared to uranium isotope and iron speciation data. (c–d) marine organic carbon and pyrite burial on the shelf. (e–f) carbon-sulfur isotopes.
A recent study reveals that "Berenicea", a group of cyclostome bryozoans, has continuously decreased in zooid size over the past 200 million years, showing an evolutionary trend opposite to "Cope's Rule". This research was completed through collaboration between MA Junye from the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS), Lee Hsiang Liow from the University of Oslo, Norway, and Paul D. Taylor from the Natural History Museum, London, UK, and was published in the international academic journal Palaeontology.Body size evolution has always been a core topic in paleontological research. "Cope's Rule" describes the trend of increasing body size during the evolution of many lineages. However, a recent study focusing on bryozoans, a particular modular organism, reveals a completely different evolutionary trajectory.A recent study reveals that "Berenicea", a group of cyclostome bryozoans, has continuously decreased in zooid size over the past 200 million years, showing an evolutionary trend opposite to "Cope's Rule". This research was completed through collaboration between MA Junye from the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS), Lee Hsiang Liow from the University of Oslo, Norway, and Paul D. Taylor from the Natural History Museum, London, UK, and was published in the international academic journal Palaeontology.By measuring 200 samples of "Berenicea" morphotype bryozoans from the Late Triassic to the present, the research team discovered a significant decrease in the maximum zooid width over time. This trend contrasts sharply with the long-term stability of zooid size in cheilostome bryozoans, challenging the previous hypothesis that the two groups shared similar body size evolution patterns.To investigate the causes, the researchers used multiple time-series models to test potential drivers such as changes in oxygen levels, the origination rate of cheilostome bryozoans, and their proportion within communities. The results show that although oxygen levels and zooid size show some statistical correlation, there is no causal relationship. Similarly, the rise of cheilostomes as a dominant group in spatial competition did not directly cause the zooid size reduction in "Berenicea".Furthermore, the study ruled out the potential influence of changes in the (paleo-)latitude (temperature) of the samples on zooid size, further highlighting the intrinsic nature of this size reduction trend. Model analysis indicates that the zooid size reduction process was not constant, but showed two significant phased changes around 165 to 160 million years ago and around 78 million years ago.This study is the first to systematically reveal the phenomenon of zooid size reduction in cyclostome bryozoans over macroevolutionary timescales. It proposes that this trend might be related to metabolic efficiency optimization or shifts in feeding ecological niches, rather than being a direct result of external environmental pressures or interspecific competition. This finding provides a new perspective for understanding body size evolution in modular organisms.Reference: Ma, Junye; Liow, Lee Hsiang; Taylor, Paul D. (2025). Zooid size reduction in cyclostome bryozoans from the Late Triassic to the present-day. Palaeontology. https://doi.org/10.1111/pala.70027.Fig.1 Cyclostome bryozoans of the ‘Berenicea’ morphotype.Fig.2 Raw data of zooid width through time for 200 colonies of ‘Berenicea’.Fig.3 The models that best fit ‘Berenicea’ zooid size data.
