华南二叠-三叠纪之交深水相生物的衰退规律及其环境过程

Deep-water facies is here referred to the uppermost Permian siliceous mudstones and cherts where deep-water radiolarians and cephalopods were abundant in South China. The systematic survey to different kinds of animals and the related palaeoenvironmental evolution of deep-water facies during the prelude of the end-Permian extinction has seldom conducted and will provide new evidence and insights for the great extinction. This project will conduct research on the taxonomy, diversity, abundance, morphology of ChanghsingianInduan radiolarians, brachiopods, bivalves and cephalopods from deep-water facies in South China, in order to investigate the disappearing/replacement process of different kinds of animals and the evolution of palaeoenvironments during the prelude of end-Permian mass extinction. In detail, the project will survey the following 3 issues. Firstly, this project analyzes the evolution of deep-water ecosystem in terms of food chain (e.g., radiolarians representing the protozoan or primary consumers, brachiopods and bivalves representing the metazoan or secondary consumers and cephalopods representing high-rank carnivores in terms of trophic levels), in order to understand the relationship between the evolution of food chain and biotic deterioration (namely, whether the break of food chain did lead to the biotic deterioration or not). Secondly, the project undertakes study on the replacement of different kinds of animal tiering and lifestyle in deep-water facies, in order to understand the ecosystem changes of varied palaeobathymetry through time and reconstruct on the process of latest Permian-earliest Triassic environmental deterioration. For example, among benthic animals, planktons or nektons, which one did disappear earlier? That will indicate bottom waters, water columns or surface waters firstly became unfavorable (e.g., anoxia) for some animals. Additionally, the project will test reasons for palaeoenvironmental changes of varied water depths, using by the study of quantitative palaeoecology and sedimentary.

二叠-三叠纪之交深水相多门类生物的深入、系统和综合研究将为全面解读生物大灭绝事件和环境危机发展过程提供新认识。本项目拟采用半定量或定量统计方法对华南长兴阶-三叠系底部深水相多门类生物（包括腕足类、双壳类、头足类和放射虫）分类学、属种分异度和丰度、生态位（Tiering）等进行深入研究。在此基础上，剖析深水生态系统营养结构的演变，探索生物之间是否存在相互影响以及生物灭绝的内因；揭示深水相不同门类生物灭绝或者衰退的先后顺序，研究生物和生活方式的更替，恢复深水底部、水体表层等不同水深环境在纵向上随时间的灾变过程。辅以古生态学、沉积学等方法研究古环境演变过程，包括海平面变化、氧化-还原环境的变化、火山作用等，为不同门类生物更替所揭示的环境演变提供佐证，深入探索深水相灾变环境发生的过程，为中-古之交生物大灭绝的研究提供新思路和新证据。

深水相不同生境的生物衰退规律研究对揭示二叠-三叠纪之交深水生态系统和环境危机过程具有极其重要的意义。.古生物分类学取得重要进展。系统描述深水相二叠-三叠纪之交腕足类29属57种（建立1新科、3新属和8新种），澄清部分属种的同物异名和异物同名现象。对放射虫follicucullid尝试开展分支系统学研究，认为Pseudoalbaillella、Longtanella、Follicucullus、Cariver具有共同的近裔祖先，为Neoalbaillella、Albaillella的系统演化和生物地层研究提供了依据。.奠定了高精度地层对比的重要基础。对主干剖面二叠-三叠纪之交开展详细的生物地层研究。在桑植剖面划分出牙形石Clarkina wangi、C. changxingensis、C. yini、C. meishanensis、Hindeodus changxingensis和H. parvus带；在其他主干剖面划分出菊石Sinoceltites、Pseudotirolites-Rotodiscoceras、Hypophiceras、Ophiceras带，以及放射虫Neoalbaillella ornithoformis和N. optima带。结合地质事件，识别出深水相二叠-三叠系界线及其上、下地层划分的标志，为二叠-三叠纪之交生物多样性与古环境演变奠定了重要基础。.对黔桂深水盆地栖居于不同水深的生物的衰退规律进行研究，发现：深水放射虫物种多样性先下降，游泳生物头足类继而消失，底栖动物腕足类和双壳类多样性最后下降。表明栖居于不同水深生物的衰退时间不同，古环境恶化可能从深水水柱开始，然后向海底和表层扩展。该现象得到了腕足类古生态学、形态功能研究的支持。研究了黔桂深水盆地二叠纪末生物古地理，提出“南盘江盆地从北往南，水体逐渐变深，受控于古特提斯洋在华南西南缘的分布。