By collecting the quadrats of three most prominent reefs in the Lazhuglung-Bangdagco region and preparing a total of 1085 thin sections, the reef structure and components are studied and reconstructed in detail. By collecting the quadrats of three most prominent reefs in the Lazhuglung-Bangdagco region and preparing a total of 1085 thin sections, the reef structure and components are studied and reconstructed in detail. This study has been published in international paleontological journal Palaeoworld. North Qiangtang Block is located in the central region of north Tibet, between the Longmuco-Shuanghu and Xijinwulan-Jinshajiang suture zones. Among the regions, the Paleozoic strata in Ngari Prefecture of North Tibet are widespread and relatively complete. However, as the average elevation of the region is over 5000 meters, as well as harsh environmental conditions and inconvenient transportations, geological researches in the region progressed slowly. The paleogeographic evolution of North Qiangtang Block in Tibet is a hot topic in recent years, particularly concerning the location and affiliation of the North Qiangtang Block and adjacent terranes. In addition, the North Qiangtang Block is an important potential oil and gas reservoir. Understanding the paleogeographic evolution of North Qiangtang Block is beneficial for a deep understanding of the petroleum geological conditions and significant for the petroleum explorations in the future. During the field trip supported by the Second Tibetan Plateau Scientific Expedition Program, Associate Professors LIANG Kun, CHEN Wei, Assistant Professor SHENG Qingyi, Professor ZHANG Yichun and other team members from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) carried out comprehensive geological investigations and found typical mound-shaped patch reefs besides the Shouxinghu lake. It is found that the patch reefs are constructed mainly by 10 species of corals and stromatoporoids, forming rigid and stable reefs by a combination of framestone and coverstone. Complex biotic interactions among the reef organisms are also found, which fits the features of mesophotic coral ecosystems. Previous studies have controversial opinions in the affiliation of the Lazhuglung-Bangdagco region. While in this study, it is found that the main reef builders, two species of stromatoporoid Gerronostromaria, possessing closely spaced laminae and pillars, co-occur in the Lazhuglung-Bangdagco region, Changdu and South China and distributed only among the three terranes. “Therefore, our study provides new evidence to prove the close paleobiogeographic affinity between Lazhuglung-Bangdagco region, Changdu and South China”, says LIANG. In addition, according to the assemblages of tabulate corals and stromatoporoids, the reefs belong to Middle Devonian Givetian in age. Therefore, the Devonian strata in Lazhuglung-Bangdagco region extends at least to the Middle Devonian, which enhances our understanding on the stratigraphic distribution features of the regions. This study was supported by the grants from the Second Tibetan Plateau Scientific Expedition and Research Program, Chinese Academy of Sciences, and the National Science Foundation of China. Reference: Liang K., Zhang Y-C., Chen J-T., Luo M., Guo W., Qie W-K., Middle Devonian (Givetian) coral-stromatoporoid patch reefs from the Lazhuglung Formation, Xizang (Tibet) and their palaeoecological and palaeogeographical implications, 2023, Palaeoworld, https://doi.org/10.1016/j.palwor.2023.02.005. Fig. 1. Field photo of Shouxinghu and an overview of Middle Devonian patch reefs in the Lazhuglung-Bangdagco region
Fig. 2. Reef components and the major reef builders tabulate coral Alveolites and stromatoporoid Gerronostromaria in the patch reefs
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
“According our research results, the Jiangshan-Changshan-Yushan Triangle area had the highest diversity level in terms of stromatoporoids”,says LIANG Kun, who from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS). “According our research results, the Jiangshan-Changshan-Yushan Triangle area had the highest diversity level in terms of stromatoporoids”,says LIANG Kun, who from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS). Benefited from international cooperations, Ph. D student JEON Juwan, Associate Professor LIANG Kun, and Prof. ZHANG Yuandong from NIGPAS carried out comprehensive systematic, paleoecological, and paleogeographic studies from the Late Ordovician Xiazhen and Sanqushan Formations from the Jiangshan-Changshan-Yushan Triangle between Jiangxi and Zhejiang Provinces of South China. The studies have been published in international paleontological journals Journal of Paleontology and Palaeoworld. The study concerning labechiid stromatoporoids was published as a cover article in Journal of Paleontology. The studies reported a total of 9 species of Clathrodictyida and 16 species of Labechiida, among which 4 are new and 4 are undetermined species. Compared with the Gondwana and adjacent terranes, the Jiangshan-Changshan-Yushan Triangle area had the highest diversity level in terms of stromatoporoids, possibly caused by the northward shift of South China in the northeastern peri-Gondwanan region during the Middle to Late Ordovician that have facilitated the development of a favorable environment for the migration of stromatoporoids among peri-Gondwanan terranes. The studies also reported new discoveries in terms of palaeoecological aspects and found the earliest known spatial competition between different individual stromatoporoids and the intergrowth between stromatoporoids and corals. On the other hand, the studies adopted network analysis on the Late Ordovician stromatoporoids to a global scale and divided the stromatoporoid fauna into three provinces: The peri-Gondwana–Tarim–Altai, Laurentia, Baltica. As a background knowledge, stromatoporoids, commonly regarded as hypercalcified sponges, lived in warm, shallow marine environments and formed rigid reefs together with corals, bryozoans, as well as cynobacteria. They were important Palaeozoic facies indicators as their external growth forms varied according to the changes of the environments. The early development of stromatoporoids were dominated by labechiids, and other stromatoporoid groups (i.e., clathrodictyids and actinostromatids) emerged in the Late Ordovician. Among these groups, clathrodictyids achieved worldwide distribution quickly along with their appearances in the Katian. The studies were supported by the Chinese Academy of Sciences and the National Natural Science Foundation of China. Reference: Jeon, J., Liang, K.*, Kershaw, S., Park, J., Lee, M., Zhang, Y.-D. 2022. Rise of Event: insights from the Upper Ordovician Xiazhen Formation of South China. Journal of Paleontology. 96, 1285–1317. https://doi.org/10.1017/jpa.2022.36. Jeon, J., Liang, K. *, Kershaw, S., Park, J., Zhang, Y.-D. 2022. Diverse labechiid stromatoporoids from the Upper Ordovician Xiazhen Formation of South China and their paleobiogeographic implications. Journal of Paleontology. 96, 513–538. https://doi.org/10.1017/jpa.2021.105. Jeon J, Li Q.-J., Na L., Liang K*, Zhang, Y.-D. 2022. Skeletal variation in the early clathrodictyid stromatoporoids of Upper Ordovician and its paleoecological and phylogenetic implications. Palaeoworld, 31: 58–68. https://doi.org/10.1016/j.palwor.2021.01.005. Jeon, J., Liang, K.*, Lee, M., Kershaw, S. 2020. Earliest known spatial competition between stromatoporoids: evidence from the Upper Ordovician Xiazhen Formation of South China. Journal of Paleontology, 94, 1–10. https://doi.org/10.1017/jpa.2019.63.
Fig. 1. Network analysis and palaeogeography of Late Ordovician stromatoporoids
Fig. 2. Study of Clathrodictyid stromatoporoids was published as a cover article in Journal of Paleontology
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, a detailed study on sedimentary facies and high-resolution carbonate δ13C is conducted on the Pennsylvanian and Cisuralian carbonate slope successions from the South China Block by the Ph.D. student YANG Wenli, Prof. CHEN Jitao, and other colleagues from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS). The study is published in the international journal Global and Planetary Change. Reliable carbonate carbon isotopes (δ13Ccarb) are valuable information that can reflect variations in global carbon cycling, and thus the paleoclimate and paleoceanographic conditions. However, expansion of the Gondwanan ice sheets, combined with tectonic uplift (e.g., Hercynian orogenesis), significant sea-level changes with multiple periods of significant depositional hiatus in low-latitude areas occurred during the late Pennsylvanian to early Cisuralian. Frequent subaerial exposures and stratigraphic discontinuities could have potentially altered the primary δ13Ccarb signals, which collectively hampered a valid global correlation at this time (Fig. 1). Indeed, a global δ13Ccarb record is hardly established for chemostratigraphic correlation and global carbon cycle modeling. The South China Block was located in the low-latitude region at the confluence of the eastern Paleo-Tethys Ocean and western Panthalassic Ocean during the Pennsylvanian and Cisuralian. Various sedimentary facies ranging from carbonate platforms to regional slopes and basins developed in South China during the Pennsylvanian to Cisuralian, which were well connected to open ocean waters, potentially recording a global seawater geochemical signal. Recently, a detailed study on sedimentary facies and high-resolution carbonate δ13C is conducted on the Pennsylvanian and Cisuralian carbonate slope successions from the South China Block by the Ph.D. student YANG Wenli, Prof. CHEN Jitao, and other colleagues from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS). The study is published in the international journal Global and Planetary Change. Detailed sedimentary facies analysis and high-resolution δ13Ccarb time series (Fig. 2) during the late Pennsylvanian to early Cisuralian suggest that the δ13Ccarb recorded in slope carbonates of the Luodian Basin may represent a reliable proxy for global carbon cycling. Across the Carboniferous-Permian transition, the well-coupled δ13Ccarb, atmospheric pCO2, and the inferred glacial records (Fig. 3), suggest a potential linkage between increased rate of organic carbon burial and the apex of the LPIA. The decoupling between the δ13Ccarb and atmospheric pCO2 during the middle Asselian to mid-late Sakmarian suggests that enhanced silicate weathering might have played a dominant role in drawdown of atmospheric pCO2 and sustained glaciation. The rapid negative excursion in δ13Ccarb coincide with the rapid rise of atmospheric pCO2 and the substantial decrease in inferred glacial records, suggesting that the prolonged greenhouse gas accumulation potentially drove the transition from icehouse to greenhouse climate states. The research is supported by the Strategic Priority Research Program of the Chinese Academy of Sciences and the National Natural Science Foundation of China. This is also a contribution to IGCP project 700 (Carbonate Build-Ups in South East Asia). Reference: Yang, W.L., Chen, J.T.*, Gao, B., Zhong, Y.T., Huang, X., Wang, Y.*, Qi, Y.P., Shen, K.-S., Mii, H.-S., Wang, X.-d., and Shen, S.-z., 2023. Sedimentary facies and carbon isotopes of the Upper Carboniferous to Lower Permian in South China: Implications for icehouse to greenhouse transition. Global and Planetary Change. 223, 104051. https://doi.org/10.1016/j.gloplacha.2023.104051.
Figure 1. Comparison of global trends of carbonate δ13C during the late Pennsylvanian to the Cisuralian. Figure 2. Sedimentary loggings and carbonate δ13C of the study sections. Figure 3. Correlations of δ13C from the study sections and global glacial events and atmospheric pCO2 during the late Pennsylvanian and Cisuralian. Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, Associate Professor ZHANG Yong from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), together with othe researchers from Nanjing University, Imperial College London, and Durham University, used a combination of paleomagnetic remanence and rhenium-osmium isotopes for the first time to provide reliable time constraints on the generation, migration, and accumulation of oil and gas under complex conditions. In sedimentary basins, the evolution of hydrocarbon including oil/gas generation, migration, and accumulation, as well as reservoir destruction, is often controlled by regional tectonic activities. Key to understanding the evolution is quantifying the timing of formation of the hydrocarbon and reservoir itself, which is of great value in enriching the theory of hydrocarbon evolution and improving oil and gas exploration efficiency. However, reliable time constraints often require comprehensive data on basin stratigraphy, tectonic characteristics, and reliable geothermal parameters, which have always been a challenge in the oil and gas geology industry. Recently, Associate Professor ZHANG Yong from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), together with othe researchers from Nanjing University, Imperial College London, and Durham University, used a combination of paleomagnetic remanence and rhenium-osmium isotopes for the first time to provide reliable time constraints on the generation, migration, and accumulation of oil and gas under complex conditions. The work was recently published in the natural index journal Journal of Geophysical Research Solid Earth. This study focused on oil/bitumen-bearing Permian carbonate rocks in the northwestern margin of the Sichuan Basin. The reservoir carbonate rocks were selected for the study of remagnetization, which revealed two periods of oil and gas migration into the reservoir carbonate rocks during the late Triassic and Middle Jurassic-Cretaceous. ZHANG says, "rhenium-osmium isotope studies on corresponding crucial oil and bitumen revealed the times for oil and gas generation, which were during ~264 Ma and ~94 Ma". The two methods therefore reliably identified two periods of hydrocarbon formation, followed by two extended periods of hydrocarbon migration. Together with the geology context, we suggest that the main geological structures for migrating and entrapping of hydrocarbon formed during the Indosinian event; the Dongwu magmatism and Yanshan tectonism provided the heat for hydrocarbon maturation, and the latter may also have reactived migration paths. The study also pointed out that the two methods are completely independent in terms of methods and principles, but they can reveal the same oil and gas process, so the two methods can provide additional tests for each dating technique. Moreover, this combined method is particularly powerful as it is independent of the hydrocarbon source rock and complex geological settings. This research was supported by the National Natural Science Foundation of China and Chinese Academy of Sciences projects. Reference: Hu Jing, Zhang Yong*, Dong Jia*, Adrian Muxworthy, David Selby, Li Yongxiang, Matthew J. Brzozowski, Wei Guoqi, Cao Jian, Yin Hongwei, Li Wei, 2023. Combining paleomagnetic and Re–Os isotope data to date hydrocarbon generation and accumulation processes，Journal of Geophysical Research: Solid Earth, e2022JB025955. https://doi.org/10.1029/2022JB025955. Relationship between hydrocarbon evolution and tectonic events Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, Papers in Palaeontology represents the first study of morphological variation in Cribroconcha honggulelengensis using a geometric morphometric approach and demonstrating allometric growth patterns for this species. This study also makes comparisons with the ontogeny of extant ostracods and investigates the control factors of Ostracoda ontogeny. Recently, Papers in Palaeontology represents the first study of morphological variation in Cribroconcha honggulelengensis using a geometric morphometric approach and demonstrating allometric growth patterns for this species. This study also makes comparisons with the ontogeny of extant ostracods and investigates the control factors of Ostracoda ontogeny. Ostracoda is one of the most widespread and diverse groups of crustaceans occurring since the Early Ordovician with many thousands of described fossil species. However, despite being the most abundant ostracods during the Palaeozoic, the Subclass Podocopa remains poorly resolved (especially for the order Platycopida) in respect of its origin, evolution, ontogeny and phylogeny, due to the lack of soft-part and molecular evidences. Dr. SONG Junjun, Prof. HUANG Bing and Prof. QIE Wenkun from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) made a thorough analysis of Cribroconcha honggulelengensis, which is a typical Platycopida species in the Late Devonian. In this study, a total of 178 specimens of C. honggulelengensis from the Upper Devonian Hongguleleng Formation of the Bulongour section in western Junggar, northwest of Xinjiang Uygur Autonomous Region (referred to as Xinjiang), NW China, were carefully selected. A combination of landmarks and semilandmarks were used to cover as many morphological details as possible for the geometric morphometric analysis. Five growth stages (i.e., Adult, from A-1 to A-4) of C. honggulelengensis have been recognized according to the result of Kernel density map combined with the length/height scatter plot. There is a strong relationship between shape and size, with juvenile specimens (from the stages A-4 to A-2), exhibiting higher variability in shape. During the early molt phase, the juveniles have rounded anterior and posterior borders with an ovate outline, while small and rare pores locate in the posteromedian of carapaces. As the valve grows larger, carapaces elongate with small radius of curvature at anterior and posterior borders, and the pores-transverse ridges area expands drastically, including large and dense pores. Compared with the living ostracods, the researchers made functional morphological analysis of C. honggulelengensis and deduced that as the ontological variable changes, its body plan may have changed in a direction that make it more favorable, namely, forage more efficiently and to flee from predators more quickly. The distinct ontogenetic shifts in C. honggulelengensis of the first allometric phase (i.e., stages A-4, A-3) and second allometric growth phase (i.e., Stage A-2) show that shape variation may be not only a result of genetic homogeneity, but also a response to environment adaptation for salinity, oxygenation and water energy. In this study, the researchers incorporate as much quantitative shape information as possible from the Late Devonian ostracods for the first time by applying the geometric morphometrics, and it will encourage the use of geometric morphometric analyses in ostracodology and other microfossils, especially for the Palaeozoic ostracods. This research was supported by the National Natural Science Foundation of China, and the Strategic Priority Research Program of the Chinese Academy of Sciences. Reference: Song, J. J. *, Huang, B., Qie, W.K., 2023. Allometry in Late Devonian Podocopa ostracods (Crustacea) and its implications for ostracod ontogeny. Papers in Palaeontology, e1480, https://doi.org/10.1002/spp2.1480.
Fig. 1. Kernel density maps with the Length/height scatter plot (A) showing the growth stages (B) of Cribroconcha honggulelengensis Song & Crasquin, 2017 (178 specimens) in the Upper Devonian Hongguleleng Formation of western Junggar, NW China.
Fig. 2. Plots for PC 1–2 (A) and PC 1–3 (B) of the Principal component analysis of the shape of right later view of Cribroconcha honggulelengensis Song & Crasquin, 2017 (178 specimens) in the Upper Devonian Hongguleleng Formation of western Junggar, NW China, visualizing shape variation by thin plate splines.
Fig.3. The linear regressions of the shape with length (A, B, C) and height of the stage A-4 (D).
Fig.4. Ecological reconstruction and life mode interpretation of Cribroconcha honggulelengensis Song & Crasquin, 2017 in the Upper Devonian Hongguleleng Formation of western Junggar, NW China
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
This study provides new secondary carbonate (microcodium) 87Sr/86Sr record and integrates multi-proxy records from the central CLP to reinterpret the response of the EAWM to insolation and ice-sheet forcing during glacial inceptions. Microcodium 87Sr/86Sr record, which captures the global cooling trend at the transition zones between the paleosol layer and the overlying loess layer, provides an independent age control for comparing loess records with other paleoclimatic records during glacial inceptions. The East Asian winter monsoon (EAWM), a major component of the East Asian monsoon circulation, is characterized by prevailing low-level northwesterly winds tightly linked to the high-northern-latitude climate via the Siberian-Mongolian High. Our current understanding of the EAWM dynamics during the glacial-interglacial cycles is mostly based on loess records on the Chinese Loess Plateau (CLP), which suggest that the EAWM intensity is closely linked to the volume of the Northern Hemisphere ice sheets (NHIS) on orbital timescale. However, unlike the "sawtooth" pattern of global ice volume that shows a gradual build-up of the ice sheets (in ~90000 years) followed by rapid deglaciation (in ~10000 years) since the middle Pleistocene transition as documented by the benthic δ18O records, the loess records of EAWM show distinct glacial and interglacial modes, with the transitions between them generally being quick. This dissimilar evolution pattern between the EAWM and the global ice volume (and NHIS) at the interglacial-glacial transitions means that some key information is missing regarding the dynamics of the EAWM during the glacial inceptions. Recently, Associate Professor LI Tao from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), in collaboration with Profs. LI Gaojun, CHEN Tianyu, ZHAO Liang, JI Junfeng, CHEN Jun, and Dr. LI Le from Nanjing University, Prof. SUN Youbin and Dr. ZHANG Zeke from the Institute of Earth Environment (CAS), Prof. YIN Qiuzhen and Dr. WU Zhipeng from Université catholique de Louvain, Dr. MENG Xianqiang from Nanjing Institute of Geography and Limnology (CAS), and Prof. Robinson F. Laura from University of Bristol, carried out a high-resolution secondary carbonate (microcodium) Sr isotope (87Sr/86Sr) study from two loess-paleosol sequences on the central CLP, yielding an independent chronology framework for assessing the evolution and potential forcing mechanisms of the EAWM during glacial inceptions over the last 550,000 years (Fig. 1). The research results were published in the internationally recognized journal Geophysical Research Letters. Building upon this independent chronology and integrating multi-proxy records, the results offer new insights into the dynamics of the EAWM during glacial inceptions and provide compelling evidence for the millennial-scale teleconnections between the high- and middle-latitudes in terminating the interglacial period in the Northern Hemisphere. This study provides new secondary carbonate (microcodium) 87Sr/86Sr record and integrates multi-proxy records from the central CLP to reinterpret the response of the EAWM to insolation and ice-sheet forcing during glacial inceptions. Microcodium 87Sr/86Sr record, which captures the global cooling trend at the transition zones between the paleosol layer and the overlying loess layer, provides an independent age control for comparing loess records with other paleoclimatic records during glacial inceptions. At the mid-way of glacial cooling, abrupt coarsening occurred synchronously with rapid positive shifts in the hydrogen and oxygen isotopic compositions of precipitation, indicating concurrent abrupt shifts in the EAWM and EASM during glacial inceptions (Fig. 2). The gradual declining summer insolation in Northern Hemisphere high-latitudes during glacial inceptions may trigger an abrupt weakening of Atlantic meridional overturning circulation (AMOC) and thus cooling in the northern North Atlantic, which strengthens the Siberian–Mongolian High cell and the EAWM but weakens the EASM. Nevertheless, the insolation-triggered abrupt weakening of AMOC alone cannot account for the mode shift in the EAWM during glacial inceptions. For example, the δ18O record from the Iberian Margin and the modeling results both indicate a sharp weakening of AMOC at the Marine Isotope Stage (MIS) 5e/5d transition while the loess records show no significant changes in the EAWM from MIS 5e to MIS 5a. This indicates that the gradual build-up of the NHIS may have played an important role in preconditioning the rapid, coupled shifts in the EAWM and EASM at during the glacial inceptions. The key role of NHIS in modulating the insolation-triggered abrupt changes in the EAWM at the end of interglacial is further supported by the absence of an abrupt shift in the EAWM at the MIS 11/10 transition when the build-up of NHIS is delayed due to the eccentricity minima. "Our results thus provide compelling evidence for the nonlinear response of the EAWM to ice volume and insolation forcing during the interglacial-glacial transitions", says LI. This research was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of the Chinese Academy of Sciences. Reference: Li, T., Li, G.*, Chen, T., Sun, Y., Yin, Q., Wu, Z., Robinson, L.F., Li, L., Zhang, Z., Meng, X., Zhao, L., Ji, J., Chen, J., 2023. Ice Volume and Insolation Forcing of Abrupt Strengthening of East Asian Winter Monsoon During Glacial Inceptions. Geophysical Research Letters 50. https://doi.org/10.1029/2022GL102404. Fig. 1 Proxy variations of Xifeng and Zhenyuan loess sequences compared to the LR04 benthic δ18O stack.
Fig. 2 Comparison of loess proxy records with other paleoclimatic records over the last 550,000 years.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, Quaternary Geochronology published the first systematic investigation on the U-series isotope geochemistry as well as the early diagenetic imprints of fossil land snail shells (Cathaica sp.) from the Mangshan loess-paleosol sequence in Henan province, central China. Recently, Quaternary Geochronology published the first systematic investigation on the U-series isotope geochemistry as well as the early diagenetic imprints of fossil land snail shells (Cathaica sp.) from the Mangshan loess-paleosol sequence in Henan province, central China. This study was conducted by Associate Professor LI Tao from the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS), in collaboration with Profs. CHEN Tianyu, LI Gaojun, LIU Yuanyuan, and Dr. WANG Maoyu from Nanjing University, and Prof. Robinson F. Laura and Dr. Knowles Tim from University of Bristol. Several geochemical techniques, including Raman microscopy, SEM, LA-ICPMS, LA-MC-ICPMS, solution-MC-ICPMS, and AMS 14C dating, were employed to investigate the mineralogy, chemical and isotopic compositions of both modern and fossil snail shells to micrometer level. Terrestrial mollusks, which have been considered as typical "index animals" due to their sensitivity to climate change, are widely distributed in the semi-arid to arid region of China, such as Chinese Loess Plateau (CLP). So far, the assemblages of land snail fossils on the CLP have been used to prove the wind-blown origin of the Neogene loess sequences and red clay, and to reconstruct monsoonal environmental change in East Asia ranging from tectonic to orbital, and even millennial timescales. Growing studies have focused on the geochemical proxies recorded by their calcium carbonate shells, mainly including stable carbon (δ13C) and oxygen (δ18O) isotopes and clumped isotopes (Δ47). Despite the wide application of these geochemical proxies of fossil snail shells in paleoclimatic reconstruction, it remains elusive to what extent they were influenced by the diagenetic alteration. No investigation has been conducted regarding the early diagenetic pathways which could alter the geochemical compositions of fossil land snail shells. Another key advantage of land snail shells is that they can be absolutely dated by several methods, including 14C dating, electron spin resonance (ESR) dating, amino acid racemization (AAR) dating, and, potentially, U-Th dating, which helps to provide age constraints on loess deposits on the CLP. Among those geochronological approaches, U-Th dating is a very powerful technique due to its wide age coverage (0 to 640,000 years) and solid theoretical foundation. However, obtaining accurate U-series dates from both marine and terrestrial mollusk shells has remained an outstanding issue for more than 50 years. A major challenge faced is that a significant amount of U in the shell is incorporated during the diagenetic episode after the burial of the shell into the sediment, suggesting apparent "open-system" behavior concerning the U-series disequilibrium. On the CLP where fossil snail shells can be buried and isolated quickly from the influence of meteoric water due to the relatively high sedimentation rate of eolian dust and the semi-arid to the arid climate, it is possible that diagenesis might occur only in the very early stage when pore-water is still able to alter the composition and structure of the snail shells. Therefore, land snail shells on the CLP may serve as a datable archive that can be used for U-Th dating. In turn, a clear understanding on the U-Th systematics of land snail shells would also help to constrain the reliability of shell-based geochemical proxies in paleoclimatic reconstructions. Based on the Raman and SEM observations, it is clear that the fossil shell is characterized by an elevated degree of porosity and a higher content of organic matter. The trace elemental composition of the fossil Cathaica sp. shell has also been largely reset, which is linked to the diffusion and adsorption of organic matter into the fossil shell during the early diagenetic alternation of fossil Cathaica sp. shells. U-series data acquired via LA-MC-ICPMS show that [234U/238U] and [230Th/238U] values are relatively homogeneous throughout the shell and the calculated apparent U-Th dates are within analytical error consistent with corresponding solution MC-ICPMS results, demonstrating the homogeneous distribution of [234U/238U] and [230Th/238U] within the fossil Cathaica sp. shells. However, the apparent closed system U-Th ages of fossil Cathaica sp. shells are found to be systematically younger (~6,000 to 13,000 years) than their paired shell 14C ages. By evaluating possible U uptake scenarios, this study suggests that this apparent age discrepancy is related to the early diagenetic uptake of U and later close system behavior likely due to the isolation of fossil shell from the influence of pore waters. This research was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of the Chinese Academy of Sciences. Reference: Li, T.*, Chen, T.*, Robinson, L.F., Wang, M., Li, G., Liu, Y., Knowles, T.D.J., 2023. Early diagenetic imprints and U-Th isotope systematics of fossil land snail shells from the Chinese Loess Plateau. Quaternary Geochronology 74, 101417. https://doi.org/10.1016/j.quageo.2022.101417.
Fig. 1 Raman fluorescence and elemental mapping across the aperture part of both modern and fossil Cathaica sp. shells.
Fig. 2 The depth profiles of (a) U concentration, (b) Th concentration and (c) apparent U-Th age and 14C age compared with published quartz SAR chronology for the Mangshan section.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Stromatoporoids are hypercalcified sponges that first became important in shallow-marine reefal systems in the Middle Ordovician, continuing as dominant reef components until Late Devonian time. The labechiid group has been regarded as the earliest stromatoporoid-type sponge based on its occurrence in the Floian Stage of the Lower Ordovician in South China. This group diversified substantially in the late Darriwilian of the Middle Ordovician, reaching a total of 12 genera that contributed to the Great Ordovician Biodiversification Event. Stromatoporoids are hypercalcified sponges that first became important in shallow-marine reefal systems in the Middle Ordovician, continuing as dominant reef components until Late Devonian time. The labechiid group has been regarded as the earliest stromatoporoid-type sponge based on its occurrence in the Floian Stage of the Lower Ordovician in South China. This group diversified substantially in the late Darriwilian of the Middle Ordovician, reaching a total of 12 genera that contributed to the Great Ordovician Biodiversification Event. Recently, doctoral student Juwan Jeon, Associate Professor LI Qijian, Professor ZHANG Yuandong et al. from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) and their collaborator from Brunel University report stromatoporoid fossils, which occur sporadically throughout the Xiaonanhai section, located on a hill close to the Xiaonanhai Reservoir near Anyang City in Henan Province, China. The results were published in Alcheringa on Jan. 8. Four labechiid species from the Machiakou Formation are systematically described. These species are major constituents of the Middle Ordovician endemic labechiid assemblage in North China. The Darriwilian labechiid stromatoporoid assemblage of North China represents the highest generic diversity of the Middle Ordovician stromatoporoids globally. A microbioherm is recognised in the Xiaonanhai section, constructed by mutual encrustations of Labechia variabilis and Labechiella mingshankouensis, and is comparable to other microbioherms found in the Middle Ordovician Yeongheung Formation of South Korea. Different stratigraphic ranges, migration pathways and palaeogeographic distributions amongst the Darriwilian labechiid species of North China indicate that their environmental tolerance and migration dispersal behaviour were variable. This study was jointly supported by the Youth Innovation Promotion Association of CAS, grants from the Strategic Priority Research Program (B) of CAS. Reference:Jeon, J., Li, Q.J.*, Chen, Z.Y., Liang, K., Stephen, K. & Zhang, Y.D., 2022. Labechiid stromatoporoids from the Middle Ordovician Machiakou Formation of North China and their implications for the early development of stromatoporoids. Alcheringa, 46 (03-04): 219–236. https://doi.org/10.1080/03115518.2022.2130978. Figure 1 Labechiella mingshankouensis (Ozaki 1938) from the Middle Ordovician Machiakou Formation at the Xiaonanhai section, Anyang County, Anyang, Henan Province, China.
Figure 2 Four contiguous thin sections showing the microbioherm from the Middle Ordovician Machiakou Formation in the Xiaonanhai section, Anyang County, Anyang, Henan Province, China, together with an interpretive drawing of the microbioherm.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Scientists from China, Germany and the UK led by Prof. LIU Feng from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) have revealed that pollen preserved in 250-million-year-old rocks contains abundant compounds that function like sunscreen but are produced by plants to protect themselves from harmful ultraviolet (UV-B) radiation. Scientists from China, Germany and the UK led by Prof. LIU Feng from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) have revealed that pollen preserved in 250-million-year-old rocks contains abundant compounds that function like sunscreen but are produced by plants to protect themselves from harmful ultraviolet (UV-B) radiation. The presence of these compounds suggests that a pulse of UV-B played an essential role in the end-Permian mass extinction event. The study was published in Science Advances on Jan. 6. The end-Permian mass extinction event (250 million years ago) is the most severe of the big five mass extinction events, with the loss of ~80% of marine and terrestrial species. This catastrophic loss of biodiversity resulted from a palaeoclimate emergency triggered by continental-scale volcanism that covers much of modern-day Siberia. The volcanic activity drove the release into the atmosphere of massive amounts of carbon that had been locked up in Earth's interior, thus generating large-scale greenhouse warming. Accompanying this global warming event was a collapse of the Earth’s ozone layer. Support for this theory comes from the abundant occurrence of malformed spores and pollen grains that testify to an influx of mutagenic UV irradiation. Plants require sunlight for photosynthesis but need to protect themselves and particularly their pollen from the harmful effects of UV-B radiation. "To do so, plants load the outer walls of pollen grains with compounds that function like sunscreen to protect vulnerable cells to ensure successful reproduction. Without the 'sunscreen' compounds, forests could have been sterilized, leading to the collapse of the terrestrial ecosystem," said Prof. Barry Lomax from the University of Nottingham. "We have developed a method to detect these phenolic compounds in fossil pollen grains (Alisporites-type) recovered from southern Tibet and detected much higher concentrations in those grains that were produced during the end-Permian mass extinction and peak phase of volcanic activity," said Prof. LIU. The researchers found an increase in UV-B-absorbing compounds (UACs) that coincided with a spike in mercury concentration and a decrease in carbon isotopes in the latest Permian deposits, suggesting a close temporal link between large-scale volcanic eruptions, global carbon- and mercury-cycle perturbations, and ozone-layer disruption. Elevated UV-B levels exerted far-reaching and long-lasting impacts on the entire Earth system. Recent modelling studies have demonstrated that elevated UV-B stress reduced plant biomass and terrestrial carbon storage, thus exacerbating global warming. In addition, increased concentration of phenolic compounds also makes plant tissue less easily digestible, making a hostile environment even more challenging for herbivores. "Volcanism on such a cataclysmic scale influences all aspects of the Earth system, from direct chemical changes in the atmosphere, through changes in carbon sequestration rates, to reducing the volume of nutritious food sources available for animals," said Dr. Wes Fraser from Oxford Brookes University.
Fig. 1 Alisporites-type fossil pollen recovered from Permian-Triassic transitional deposits in the Qubu section (Image by NIGPAS)
Fig. 2 The impacts of ozone depletion and elevated UV-B levels on the terrestrial ecosystem (Credit byConor Haynes-Mannering)
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
Recently, Dr. NA Lin and Dr. LI Qi-jian from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) and his collaborators from University of Erlangen-Nuremberg outline time-traceable provinces for marine invertebrates across the Cambrian period using a compositional network based on species-level fossil occurrence data. The Cambrian witnessed a noteworthy radiation in biodiversity and a remarkable divergence in Bau plans of marine metazoans. Although the temporal and spatial patterns of Cambrian biodiversity have been widely documented, less attention has been paid to the fundamental biogeographic structure and its changes through time. And it remains unclear how these changes scale up to first-order biogeographic patterns, which may provide insights into evolutionary processes during large-scale diversifications at different temporal scales. Recently, Dr. NA Lin and Dr. LI Qi-jian from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS) and his collaborators from University of Erlangen-Nuremberg outline time-traceable provinces for marine invertebrates across the Cambrian period using a compositional network based on species-level fossil occurrence data. The results have been published online in the Paleobiology, the official publication of the Paleontological Society. The study confirms an increase in regional differences (Fig. 1) of faunal composition and a decrease in by-species geographic distribution during the first three stages. The results also show that general biogeography tends to be reshaped after global extinction pulses (Fig. 2). The authors suggest that the abrupt biogeographic differentiation during the Cambrian radiation was controlled by a combination of tectonics, paleoclimate, and dispersal capacity changes. So this study provides further evidence for the evolution of biogeographic patterns during and after the Cambrian radiation. This study was jointly supported by the Youth Innovation Promotion Association of CAS, grants from the Strategic Priority Research Program (B) of CAS and the State Key Laboratory of Palaeobiology and Stratigraphy (NIGAPS). Reference: Na, L., Kocsis, á, Li, Q.*, & Kiessling, W. (2022). Coupling of geographic range and provincialism in Cambrian marine invertebrates. Paleobiology, 1-12. https://doi.org/10.1017/pab.2022.36. Figure 1 Trajectory of provinciality from the Fortunian to Stage 10 of the Cambrian, based on Hurlbert's probability of interspecific encounter (PIE). Figure 2 Paleogeographic positions of sampled bioregions for the ten 10 Cambrian stages. Numbers and colors indicate time-traceable bioregions.
Contact: LIU Yun, Propagandist Email: yunliu@nigpas.ac.cn Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing, Jiangsu 210008, China
