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Journal of Earth Science 2023年第1期34卷 156-172页

作者： Zhen Wang yiming gong State Key Laboratory of Biogeology and Environmental Geology School of Earth SciencesChina University of GeosciencesWuhan430074China

On the basis of systematic study of sedimentary facies, microfacies and geochemistry of measured strata sections and wells, the ooid shoals of the Cambrian Miaolingian Zhangxia Formation in the southern Ordos Basin are composed of both high-and low-energy ooid shoals. The characteristics of the high-energy shoals are sparry cementation, with moderate to well sorting, large grain size, high ooid content and low micrite, weak micritization, and well-preserved internal textures of the ooids. Macroscopically, the high-energy ooid shoals display a thick-bedded aggradational stacking pattern in upward coarsening and thickening sequences. The low-energy ooid shoals are mainly made up of micritic cementation, with moderate to poor sorting, relatively small grain size, lower ooid content and higher micrite, strong micritization, and poorly-preserved internal textures of the ooids. Macroscopically, the low-energy ooid shoals show a thin-bedded, interbedded stacking pattern in upward fining and thinning sequences. The sedimentological evidence and carbon isotope data show that the differences of internal fabric and sedimentary evolution of both high-and low-energy ooid shoals are closely related to the sea-level change.

关键词： Cambrian sedimentary model North China ooid shoals Ordos Basin Zhangxia Formation

Flysch Trace Fossils from the Hercynian and IndosinianOrogenic Belts of North western China andTheir Palaeoenvironmental Significance

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Acta Geologica Sinica(English Edition) 1999年第4期73卷 384-394,495-499页

作者： gong yiming Faculty of Earth Science China University of Geosciences Wuhan Hubei Province 430074

Twenty-three ichnotaxa have been found in the Silurian and Carboniferous turbidites of the Tianshan orogenic belt and the Triassic turbidites of the East Kunlun-West Qinling orogenic belt of northwestern China. They are Acanthorhaphe isp., ?Arthrophycus isp., Aulichnites parkerensis, Chondrites isp., C. intricatus, C. targionii, Cochlichnus anguineus, coprolite, Dendrotichnium haentzscheli, Helminthopsis isp., Helminthopsis abeli, H. hieroglyphica, H. cf. irregularis, Imbrichnus isp., Kunlunichnus qinghaiensis, Laevicyclus rotaeformis, Lophoctenium tianshanensis, Megagrapton isp., Micatuba verso?, Muensteria isp., Neonereites, Palaeophycus, and Zoophycos caudagalli, two of which, namely, Kunlunichnus qinghaiensis and Lophoctenium tianshanensis, are new ichnospecies. The described trace fossils can be grouped into five ichno-assemblages: the Aulichnites-Imbrichnus ichno-assemblage representing turbidity current deposits of a restricted anoxic deep-sea basin, the Lophoctenium ichno-assemblage showing the deep-sea or ocean environments relevant to a plate subduction, the Zoophycos-Helminthopsis ichnoassemblage representing the upper-middle turbidity fan deposits of a pelagic and hemipelagic environment, the Megagrapton-Chondrites ichno-assemblage representing the middle-lower turbidity fan deposits of an oceanic archipelago and the Kunlunichnus ichno-assemblage indicating bathyal turbidity current deposits.

关键词： flysch trace fossils Silurian Carboniferous Triassic Tianshan Mountains Kunlun Mountains orogenic belt northwestern China

Abnormal changes of dynamic derivatives at low reduced frequencies

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Chinese Journal of Aeronautics 2018年第7期31卷 1428-1436页

作者： Weiwei ZHANG yiming gong Yilang LIU School of Aeronautics Northwestern Polytechnical University

A number of studies have found that abnormal changes of dynamic derivatives occurred at very low reduced frequencies, but its inducement mechanism is not very clear. This paper has researched the abnormal changes and analyzed the influence on some parameters by solving the unsteady flow around forced oscillation airfoils based on Navier-Stokes equations. Results indicate that when the reduced frequency approaches to zero, the dynamic derivatives obtained by the numerical method will diverge. We have also proven it in theory that this phenomenon is not physical but completely caused by numerical singularity. Furthermore, the abnormal phenomenon can be effectively mitigated by using the time spectral method to solve the aerodynamic forces and the integral method to obtain the dynamic derivatives. When the reduced frequency is in the range of 0.001–0.01, the dynamic derivative maintains nearly unchanged for the whole speed region. This study can provide a reference for the reasonable choice of the reduced frequency in calculations and experiments of dynamic derivatives.

关键词： Dynamic derivatives Numerical diverge Reduced frequency Time spectral method Unsteady flow

Coupling relationships between brachiopods and Girvanella during the Late Devonian F-F transition in Guilin, South China

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Science China Earth Sciences 2008年第11期51卷 1581-1588页

作者： XU Ran gong yiming ZENG JianWei Key Laboratory of Biogeology and Environmental Geology of Ministry of Education State Key Laboratory of Geological Processes and Mineral ResourcesChina University of GeosciencesWuhan 430074China Institute of Resources and Environment Key Laboratory of Biogenic Traces&Sedimentary Minerals of Henan ProvinceHenan Polytechnic UniversityJiaozuo 454003China

The abundance curves derived from area proportions of brachiopods and Girvanella in the thin sections from the Yangdi section, South China, exhibits complex relationships during the Late Devonian Frasnian-Famennian transition. The living activity of brachiopods such as grazing and borrowing did great damage to the growth of Girvanella. However, there was more to just a mere a survival competing relationship between them, Girvanella actually improved marine environments by oxygenating the dysoxic ambient sea-water through photosynthesis in the lower Kellwasser Horizon. Profited from this improvement brachiopods' abundance increased subsequently and suppressed Girvanella again. Nonetheless, without Girvanella's photosynthesis, brachiopods were wiped out by the farther anoxic environments in the upper Kellwasser Horizon. The complex relationships between Girvanella and brachiopods may be a key to unlocking the relationships between geomicrobes and metazoans in the geological overturn periods.

关键词： brachiopods Girvanella anoxia Late Devonian F-F mass extinction South China

Hydrothermal activities and seawater acidification in the Late Devonian F-F transition:Evidence from geochemistry of rare earth elements

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Science China Earth Sciences 2011年第4期54卷 540-549页

作者： ZENG JianWei XU Ran gong yiming Key Laboratory of Biogeology and Environmental Geology of Ministry of Education & State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China Institute of Resources and Environment Key Laboratory of Biogenic Traces & Sedimentary Minerals of Henan Province Henan Polytechnic University Jiaozuo 454003 China

Rare-earth dements （REE） in limestones were measured by ICP-MS from the Yangdi section across the Frasnian-Famennian （F-F） transition in Guilin, Guangxi of South China. The average EREE contents of measured samples are 33.32 ppm. The average LREE/HREE ratio is 6.35. Data show LREE-enriched REE distribution pattern in the Yangdi section. Most of samples are characterized by positive Eu anomaly with average of 1.13, and there are two maxima of Eu anomaly just below the F-F boundary. Almost all analytical samples show obvious tetrad effects. Remarkable M-shaped tetrad effects are observed in these samples with positive Eu anomaly. The characters of REE and some relative elements （Fe, Mn, Al, etc.） indicate that hydro- thermal activities occurred and resulted in seawater acidification in Upper and Lower Kellwasser horizons of the Late Devonian. The changes of marine environment caused by hydrothermal activities, such as seawater acidification, heavy metal pollution, and eutrophication, would destroy the neritic ecosystem and finally result in the F-F mass extinction.

关键词： Devonian mass extinction REE hydrothermal activities tetrad effects seawater acidification

Late Devonian red tide and mass extinction

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Chinese Science Bulletin 2002年第13期47卷 1138-1144页

作者： gong yiming LI Baohua SI Yuanlan WU Yi Faculty of Earth Science China University of GeosciencesWuhan 430074China Laboratory of Marine Geology Tongji UniversityShanghai 200092China Department of Computer Science South-Central University for NationalitiesWuhan 430074China Guangxi Institute of Geology Nanning 530023China

Molecular stratigraphical, carbonate carbon isotopic, stratigraphical and paleontological data show that algal booming, eutrophication, anoxia, hypersalinity, positive δ13C excursion and biomass decreasing occurred in the offshore carbonate environments of the Frasnian-Famennian (F-F) transition, which hints that red tide might frequently take place in the F-F transition of Guangxi, South China. We suggest that the mass extinction of the reef ecosystems and the shallow-water marine organisms in the F-F transition of the lower-middle latitudes may be related to the frequent occurrence of red tide in that time.

关键词： red tide eutrophication mass extinction Devonian South China.

Composition and construction of high- and low-energy ooid shoals and their relationships with environmental changes: A case study from the Cambrian Zhangxia Formation in the Ordos Basin， North China

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Journal of Earth Science 2020年

作者： Zhen Wang yiming gong State Key Laboratory of Biogeology and Environmental Geology， School of Earth Sciences， China University of Geosciences

On the basis of systematic study of sedimentary facies， microfacies and geochemistry of measured strata sections and wells， the ooid shoals of the Cambrian Miaolingian Zhangxia Formation in the southern Ordos Basin are composed of high- and low-energy ooid shoals. The characteristics of the high-energy shoals are sparry cementation， with moderate to well sorting， large grain size， high ooid content and low micrite， weak micritization， and well-preserved internal textures of the ooids. Macroscopically， the high-energy ooid shoals display a thick-bedded aggradational stacking pattern in upward coarsening and thickening sequences. The low-energy ooid shoals are mainly made up of micritic cementation， with moderate to poor sorting， relatively small grain size， lower ooid content and higher micrite， strong micritization， and poorly-preserved internal textures of the ooids. Macroscopically， the low-energy ooid shoals show a thin-bedded， interbedded stacking pattern in upward fining and thinning sequences. The sedimentological evidence and carbon isotope data show that the differences of internal fabric and sedimentary evolution of high- and low-energy ooid shoals are closely related to the changes of sea levels.

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Phosphatic microspherules and their geobiological implications from the Frasnian-Famennian transition at the Yangdi section, Guilin, South China

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Science China Earth Sciences 2014年第6期57卷 943-956页

作者： HUANG Cheng gong yiming State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences

Abundant perfectly-preserved phosphatic microspherules have been discovered across the Frasnian-Famennian （F-F） transition from the Yangdi section in Guilin, Guangxi, South China. They are mostly spherical or elliptical in shape and about 150 gin in diameter with smooth exterior surfaces. Each microspherule consistently possesses a small dimple on the surface. The internal texture of microspherules consists of concentric light-colored apatite and dark-colored organic matter bands alternating around a central core. Conodonts have also been found preserved together with phosphatic microspherules in the same horizon, and the abundance of the former is obviously higher than that of the latter. Laser Raman spectral studies show close similarities in spectral patterns between the outer shells of phosphatic microspherules and the blade of the conodont genus Palmatolepis sp., as well as between the microspherule nucleus and the platform of the same conodont genus. Furthermore, the statistical results and geochemical data demonstrate that the elevated abundance of phosphatic microspherules roughly coincides with the blooms of bacteria and algae, but is later than the sharp increase of oceanic nutrients. The phosphatic microspherules are inter- preted here to be the ＇otoliths＇ secreted by conodont animals based on the compositional similarities between phosphatic mi- crospherules and conodonts and their interrelated abundances. In addition, an analogous study reveals morphological and tex- tural similarities between fish otoliths and phosphatic microspherules. The formation of phosphatic microspherules is probably related to seawater eutrophication. We speculate that the explosive growth of bacteria and algae is probably caused by the en- richment of nutrients that is most likely associated with the increase of terrestrial inputs, submarine hydrothermal activities or the upwelling anoxic bottom waters in the late Devonian, which would stimulate the conodont animals to secrete

关键词： microspherules conodont animal otoliths eutrophication Devonian F-F South China

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The discovery of early Permian reef belt in east Kunlun and its significance

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Chinese Science Bulletin 1998年第11期43卷 947-950页

作者： Wang Yongbiao Zhang Kexing gong yiming Zhang Zhi Luo Mansheng China Univ Geosci Fac Earth Sci Wuhan 430074 Peoples R China

The early permian reef belt is distributed in the southern side of eastern Kunlun, north area of Qinghai-Tibet Plateau. The core-reef facies of the reef extends from Tuosuo Lake to Huashixia. Lots of reef breccia was found at the southern slope of the core-reef belt, and to the north of the reef belt there is back-reef limestone. Cacisponges, hydrozoa, bryozoa, Tabulozoa, Tubiphytes and red algae are the main frame-building organisms. Archaeolithoporella, laminated blue-green algaes, Tabulozoa and Tubiphytes played a role of binding or encrustating. There are many kinds of epibiont in the reef, including brachiopod, gasteropod, foraminifera, echinoderm and simple coral. The type and the characteristics of the reef-building organisms in eastern Kunlun and Animaqing are basically the same as those in the south of

关键词： reef early Permian east Kunlun.

Microbial and molecular fossils from the Permian Zoophycos in South China

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Science China Earth Sciences 2007年第8期50卷 1121-1127页

作者： gong yiming XU Ran XIE ShuCheng HUANG XianYu HU Bin QI YongAn ZHANG GuoCheng Key Laboratory of Biogeology and Environmental Geology of Ministry of Education State Key Laboratory of Geological Processes and Mineral ResourcesChina University of GeosciencesWuhan 430074China Institute of Resources and Environment Key Laboratory of Biogenic Traces&Sedimentary Minerals of Henan ProvinceHenan Polytechnic UniversityJiaozuo 454003China

The trace fossil Zoophycos was enriched in the lower part of the Guadalupian Maokou Formation of Permian in Laibin, Guangxi of South China, and characterized by observable lamellae within its spreiten. Associated with these lamellae are the prolific coccus- and spirillum-shaped microbe fossils. These microbes morphologically identified are 0.4―3.0 μm in diameter or length. Molecular fossils, including normal alkanes (dominated by C18, without an odd-over-even predominance), acyclic isoprenoids (such as pristane (Pr) and phytane (Ph)), extended tricyclic terpanes, pentacyclic triterpanes, steranes, al-kylcyclohexanes, dibenzothiophenes, benzonaphthothiophenes, benzobisbenzothiophenes, were in-strumentally identified in the wackestone characterized by the occurrence of abundant Zoophycos (composite ichnofabric indices are 4) and crowded microbial fossils. The value of the Pr/Ph ratio is less than 1, indicative of a dysoxic condition. The identification of abundant sulfur compounds (the thio-phene series) related to the contribution of reductive sulfur favors the occurrence of sulphate-reducing bacteria. The association of abundant microbial colonies with microbial molecular fossils within the spreiten suggests that trace fossils Zoophycos would be a multifunctional garden carefully constructed by the Zoophycos-producer, where different microbial colonies were orderly and carefully planted and cultured in different minor lamellae within spreiten. Hence, it is proposed that the Zoophycos-producer symbiosed with microbial colonies on the mutual basis of food supply and the redox conditions.

关键词： trace fossils Zoophycos microbes molecular fossils Permian South China