华南早-中二叠世小有孔虫的辐射演化及其生态特征

Radiation and extinction are two different forms to go through the process of evolution. Currently，small foraminifera and environmental response in the Permian extinction period has become a hot topic, but about radiation and extinction of foraminifera environmental assessment of the merits of the lack of clear targets. For the scientific issue, the project will be small foraminifera of the Early-Middle Permian in southwest China for the study. What is the normal environment or ecosystem optimization index of small foraminifera will be the focus of this research project. Applicants recent analysis found that it is significantly different morphological characteristics of radiation and extinction period, which indicates that their function morphology may change, Here will serve as the entry point of this study. This project intends to select small foraminiferal fossils from 2-3 profiles of the Early- Permian in south China for the study, taking quantitative paleontology, stratigraphy and geochemical methods，In-depth study diversity of small foraminifera, shell morphology, commensal organisms and oxygen, and so on environmental indicators of the radiation background，Get small foraminifera nodes of adaptive radiation and normal or optimize ecosystem indicators, and so forth foraminiferal radiation evolution characteristics on the Early- Middle Permian of south China and its mechanism, and to understand the bad environment of the late Mid-Permian and ecosystem collapse of the end- Permian provide reference data.

辐射与灭绝是一个生物类群演化过程必经的两个不同的形式。目前对二叠纪灭绝时期的小有孔虫及其对环境恶化的响应研究已成为热点，针对目前对有孔虫辐射和灭绝环境的优劣缺乏一定评价指标的科学问题，本项目将以西南地区早-中二叠世有孔虫辐射高峰期的小有孔虫化石为研究对象，重点探讨有孔虫辐射期正常环境或优化生态系的指标。申请者近来分发现同一分类群的有孔虫形态学在辐射期与绝灭期存在明显差异，预示他们的形态功能可能发生变化，这将作为本项研究的切入口，在对多个剖面密集采集的小有孔虫分类学基础上，将详细提取分析各类群的形态学、多样性、共栖生物和含氧量等生态信息，结合生物地层学和地球化学方法，根据相关性数据，从而获取小有孔虫适应辐射的节点及其优化性生态系指标，其成果将有助于阐明华南早-中二叠世有孔虫辐射演化过程和机理，并可为评价或进一步理解中二叠晚期的环境恶化程度以及二叠纪末期生态系崩溃提供参照性数据。

针对二叠纪生物演化与环境关系研究中，对环境的优劣评价存在模糊的认识问题，以云南石林剖面和贵州六盘水早-中二叠世剖面为研究材料，研究揭示两地区至少产小有孔虫43属162种，其中古串珠类6属57种，构成优势类群；对古串珠虫类形态参数统计表明，房室的宽度和数目是控制壳体大小和几何形态的重要因素；有孔虫生态组合研究表明，蜓类与非蜓有孔虫及藻类的共生组合形式中生物多样性多呈峰值；综合地层学对比研究结果显示，华南早二叠世空谷阶至中二叠的沃德阶正是小有孔虫的辐射期，生物多样性处于峰值区，小有孔虫动物群中以直壳型类群占优势，且以壳体大、房室数目的属种为主，并具有蜓类+非蜓有孔虫+藻类化石组合等特征，可以视为环境优良的生物指标。项目还从古植物学角度佐证了二叠纪冈瓦纳大陆裂解由北向华南板块迁移的古气候和古地理背景。这些研究资料和认识将对提升古生代有孔虫研究深度和广度有一定促进作用，同时对从生物角度深入探讨二叠纪生物演化和绝灭事件的原因具有重要参考价值。