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early cambrian protoconodonts and conodont-like fossils from China: Taxonomic revisions and stratigraphic implications

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Progress in Natural Science:Materials International 2004年第2期 77-84页

作者： Michael STEINER,Bernd-D.ERDTMANN Technische Universitt Berlin Sekr. ACK14 Technische Universitt Berlin Sekr. ACK14 Ackerstrasse 71-76 D-13355 Berlin Germany Ackerstrasse 71-76 D-13355 Berlin Germany

Protoconodonts and conodont-like microfossils are characteristic components in the early cambrian skeletal faunas. Since the 1970s, these tooth-like phosphatic sclerite fossils have been widely recovered from the Lower cambrian of China, and altogether 25 genera and 52 species of protoconodonts and conodont-like fossils have been described, although some taxa represent synonyms or invalid taxonomic names, and some assignments are apparently inappropriate. Through a brief review and discussion, the distinction between protoconodonts and conodont-like fossils is denoted here. There are 13 genera previously assigned to protoconodonts in the literature, but present taxonomic revisions show that 5 of them are junior synonyms of other taxa, and 2 represent unknown arthropods. The other 12 genera, of which 5 also are junior synonyms, only reveal a conodont-like morphology with various zoological affinities: most of them are enigmatic, and only Beshtashella and Parafomitchella (= Beshtashella ) can be assigned to mollusks. The spatial and temporal distribution of the most genera is briefly discussed. Three intervals of stratigraphic distribution for the protoconodonts not only have significant implications for stratigraphic correlations but also may reflect their evolutionary trend.

关键词： protoconodonts conodont-like fossils Small Shelly Fossils early cambrian China.

The Occurrence of Longfengshania in the early cambrian from Haikou, Yunnan, China

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Acta Botanica Sinica 2002年第10期44卷 1250-1254页

作者：徐兆良中国科学院植物研究所北京100093

Well preserved early cambrian small individual megascopic carbonaceous algal fossils have been found from the Chengjiang Biota. This paper deals with the new megascopic algal fossils in the early cambrian also from Chengjiang Biota at Ercai Village, Haikou, Kunming, Yunnan, southwest China. Two new taxa, Longfengshania cordata sp. nov. and Plantulaformis sinensis gen. et sp. nov. are described here in detail. These new findings show that the Chengjiang Biota is high in species diversity of fossil algae and might offer new evidence for a better understanding of the cambrian explosive biological evolution. Moreover, the fossils described here might belong to the megaalgal fossils according to detailed morphological study on the relationships of Longfengshania. Additionally, the occurrence of Longfengshania in the early cambrian and the Neoproterozoic probably indicates a wide ecological tolerance and flexibility and apparently reflects its evolutionary conservation and a high degree of inherent genetic stability.

关键词： Haikou of Kunming early cambrian algal fossils

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New Discoveries of Phaeophycean Fossils in the early cambrian, Haikou, Kunming,Yunnan, Southwest China

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Acta Botanica Sinica 2001年第10期43卷 1072-1076页

作者：徐兆良中国科学院植物研究所北京100093

The paper deals with the new phaeophycean fossils in the early cambrian from Chengjiang Biota at Ercai Village of Haikou, Kunming, Yunnan, Southwest China. Three new taxa, Punctatiopsis latifolia gen. et sp. nov., P. simplex gen. et sp. nov. and Vendotaenia cf. antiqua Gnilovskaya axe described here in detail. These new findings show that the Chengjiang Biota is high in species diversity of fossil algae and might offer new evidence for a better understanding of the cambrian explosive biological evolution. The fossil genus described here is found to have a close relationship with the living Punctatia based on similar morphology. The results suggest that the Chengjiang Biota in Haikou area of Kunming was living in an intertidal and subtidal seawater environment.

关键词： Haikou of Yunnan early cambrian phaeophycean fossils

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Initial organic geochemical investigation on Late Neoproterozoic-early cambrian sediments in the Yangtze region, China

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Progress in Natural Science:Materials International 2003年第12期 56-61页

作者： WANG Tieguan 1*, WANG Chunjiang 1, ZHANG Weibiao 1, SHI Quan 1, ZHU Lei 1 and CHEN Junyuan 2(1. Key Laboratory of Hydrocarbon Accumulation Mechanism of the Education Ministry, University of Petroleum, Beijing 102249, China 2. Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China)

Totally 19 samples of typical Upper Proterozoic Lower cambrian sedimentary rocks were collected and analyzed for an organic geochemical investigation. Almost all these rocks have high TOCs, super maturities and similar biomarker distribution. As an exception, however, the Sinian Nantuo Tillite shows much lower TOCs and little phytane and pristane in comparison with those in other strata, which implies a very faint photosynthetic process, and a restricted euphotic zone and quite limited sunlight within the sedimentary water column during the Sinian glaciation age in the western Yangtze region providing an evidence for palaeo oceanic environment of the Neoproterozoic Snowball Earth age.

关键词： Late Neoproterozoic early cambrian molecular organic geochemistry euphotic zone Snowball Earth Yangtze region.

Stable isotopic geochemistry of organic carbon and pyrite sulfur from the early cambrian black shales in Northwestern Hunan, China

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Progress in Natural Science:Materials International 2004年第2期 85-91页

作者： CAO Shuanglin 1,2 *, MA Dongsheng 1 and PAN Jiayong 1(1. State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China 2. East China Institute of Technology, Fuzhou 344000, China)

The early cambrian black shale sequence in Northwestern Hunan Province has been investigated for its stable isotopic geochemistry of organic carbon and pyrite sulfur. The relatively low δ 13 C values of organic matter, -29.7‰～-34.2‰, are interpreted as caused by the high CO 2 concentration in atmosphere/ocean and an anoxic depositional environment in early cambrian. Variable, but significantly positive δ 34 S values, +10.2‰～+28.2‰, for sedimentary pyrite reveals bacterial sulfate reduction as the pyrite-forming process but under sulfate-limited conditions. A protected anoxic basin, which had very limited access to open ocean, and its sediments, where metabolizable organic matter was rich and bioturbation was absent, are supposed to be the sulfate-limited environments and might have existed in South China in the early cambrian.

关键词： sulfur and carbon isotopes black shales early cambrian Hunan.

Isotopic evolution of the terminal Neoproterozoic and early cambrian carbon cycle on the northern Yangtze Platform, South China

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Progress in Natural Science:Materials International 2003年第12期 62-65页

作者： GUO Qingjun 1,2 *, LIU Congqiang 1, Harald STRAUSS 3 and Tatiana GOLDBERG 3(1. Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China 2. Graduate School, Chinese Academy of Science, Beijing 100018, China 3. Geologisch Palontologisches Institut, Westflische Wilhelms Universitt Münster, 48148 Münster, Germany)

Profound geotectonic, climatic and biological changes occur during the terminal Neoproterozoic and its transition into the early cambrian. These are reflected in temporal variations of the chemical and isotopic composition of seawater. We are studying a sequence of sedimentary rocks at the Shatan section, northern Yangtze Platform, Sichuan Province of China. This succession comprises, in ascending stratigraphic order, predominantly calcareous sediments of the Sinian upper Dengying Formation and black shales of the lower cambrian Guojiaba Formation (time equivalent of Niutitang Fm.). Paleoenvironmental setting represents shallow water shelf deposits. The objective of our study is to provide temporal records for the isotopic compositions of organic and carbonate carbon throughout this time interval. Organic carbon isotope values display a range between -35.8‰ and -30.1‰ with clear stratigraphic variations. Carbonate carbon isotope data vary between -3.5‰ and +0.5‰. These secular variations are interpreted to reflect perturbations of the global carbon cycle, specifically changes in the fractional burial of organic carbon. However, local conditions have further affected the isotopic signals.

关键词： terminal Neoproterozoic early cambrian carbonate and organic carbon isotopic composition Yangtze Platform Shatan section.

Microstructure and functional morphology of the early cambrian problematical fossil Rhombocorniculum

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Progress in Natural Science:Materials International 2003年第11期 31-35页

作者： Michael STEINER 13355 Berlin Ackerstrasse 71～76 Germany Technische Universitt Berlin Sekr.ACK 14

Rhombocorniculum cancellatum from the Lower cambrian of southern Shaanxi Province (South China) is represented by the dextral and sinistral tooth-like sclerites (both in nearly equal numbers), indicating that the body plan of the organism with these sclerites probably was bilaterian. The main feature of the microstructure of the sclerites is the presence of longitudinally arranged, mutually contiguous hollow tubules, the shared walls consisting of microcrystalline apatite. In transverse cross sections, the sclerite wall mainly exhibits a spongy structure, with pore size decreasing adapically. Functional morphological analysis indicates that the sclerites serve as a defensive rather than a grasping function.

关键词： early cambrian Rhombocorniculum microstructure functional morphology.

TAPHONOMY AND COMMUNITY OF THE early cambrian CHENGJIANG LAGERSTTTE FROM THE MAFANG SECTION, SW CHINA

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TAPHONOMY AND COMMUNITY OF THE EARLY CAMBRIAN CHENGJIANG LAG...

GENERIC DIVERSITY AND RADIATION PATTERNS OF early cambrian METAZOAN FOSSILS IN SOUTH CHINA

第二届国际古生物学大会

作者： Jean-Bernard CARON Department of Natural History Royal Ontario Museum100 Queen’s Park Toronto Ontario

Reconstruction of a fossil community is generally biased by time-averaging of fossil records in the sedimentary rocks. However, the rapid event layers with extraordinarily preserved soft-bodied fossils in the fossil-lagerstatte such as the Chengjiang Lagerstatte provide an opportunity to investigate the relationships between temporal community patterns and environmental changes.

关键词： Chengjiang Lagersatte taphomony palaeoecology early cambrian

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GENERIC DIVERSITY AND RADIATION PATTERNS OF EARLY CAMBRIAN M...