扬子西缘早三叠世遗迹群落演变与古环境制约

Ichnocenosis as the buried fossil communities in situ, recording original ecological and palaeoenvironmental information, and are provided good materials to study the Early Triassic recovery and palaeoenvironmental controlling factors. Through the systematic measuring the Early Triassic major and second stratigraphic sections from the western Yangtze plate, assisted by a systematic study of ichnology, sedimentology and geobiology, this subject aims to (1) diagnose the genus/species, diversity and palaeoecological association of trace fossils and construct their spatiotemporal evolution succession; (2) combining the macro- and micro-analysis of ichnofabrics, ichnotaphonomy, behavioural patterns, and sedimentary facies, reveal the evolution characteristics reflected from Early Triassic trace fossils and their palaeoenvironmental restriction mechanism. This study is the fundamental research of ichnology, sedimentology and major bio-environmental events, and supply a new material for improving and supplementing the relationship between the biotic recovery and palaeoenvironmental background in the Early Triassic.

遗迹群落作为原地埋藏的化石群落，记录了原位的生态特征及古环境信息，为研究早三叠世的生物复苏和古环境制约提供了良好的素材。本项目拟通过系统对扬子西缘早三叠世主干剖面和辅助剖面的遗迹化石进行系统遗迹学、沉积学与地球生物学分析, 构建早三叠世遗迹化石的生态组合类型及其时空演变序列；结合遗迹组构、遗迹埋藏学、遗迹行为习性、沉积相的宏观和微观分析, 查明早三叠世遗迹群落演变特征及其古环境制约机制｡ 该研究是遗迹学、沉积学和重大地质事件之间的基础性研究，为进一步诠释早三叠世生物复苏和古环境之间的耦合关系提供新材料和新认识。

二叠纪末生物大灭绝事件是显生宙最重大的一次生物灭绝事件，研究二叠纪末生物大灭绝事件之后生物复苏和海洋古生态系统的恢复，成为近十几年来地质学家尤其是古生物学和沉积学家最为关注的热点问题之一。本项目以扬子西缘早三叠世海陆过渡相四川龙门硐剖面和深水盆地相广元上寺剖面为主干剖面，辅助早三叠世深水盆地相广西东攀剖面和浙江煤山剖面，通过系统收集各剖面系统的遗迹学、沉积学和地球生物学数据，构建了二叠系-三叠系（P-T）之交遗迹群落随时空的演变序列，结合沉积学、埋藏学、遗迹组构、遗迹阶层、遗迹歧异度等综合分析，查明了P-T之交遗迹群落的阶梯性灭绝特征以及早三叠世遗迹群落演变特征的古环境制约机制，验证了半咸水环境遗迹群落并未受到晚二叠世大灭绝事件影响的假说，为二叠系-三叠系（P-T）之交边缘海环境的生物复苏和古环境之间的耦合关系提供了新材料和新认识。