中国南方晚三叠世牙形石演化及生物-环境事件研究

晚三叠世是中生代动植物群发展一个重要时期。目前全球晚三叠世各阶之间的界线层型剖面和界线层型候选剖面都位于东特提斯地区或北美。迄今除卡尼阶的底界已被确定在意大利外，晚三叠世各阶之间的界线层型尚未确定。菊石和牙形石是上三叠统划分的重要标志。因为晚三叠世菊石区域性强，跨区对比困难。高精度的牙形石生物地层学和磁性地层学可望在区域和全球对比中发挥重要的作用。中国南方地区发育良有好的海相上三叠统，是研究上三叠统的重要地区之一。本项目主要通过大样品处理进行高精度牙形石生物地层研究，并在化石丰富的剖面进行磁性地层学研究，通过牙形石氧同位素和沉积学方法研究发生在中卡尼期的“卡尼期雨季事件”是否在中国南方地区普遍存在及其对生物和环境的影响。通过高精度牙形石生物地层学和磁性地层学进行东、西特提斯地区之间的精细对比。本研究将有利于提高中国南方地区上三叠统的研究精度，深化了解晚三叠世生物-环境事件协同演化的过程。

After the end-Permian mass extinction, Late Triassic is a key period for the development of the mesozoic type faunas and floras. The present Upper Triassic chronostratigraphic scale is a hierarchy of three stages- Carnian, Norian, and Rhaetian. Conodont and ammonoid biostratigraphy play key roles for the Upper Triassic chronostratigraphy. Besides the Global boundary Stratotype Section and Point (GSSP) for the base of the Carnian Stage (Late Triassic) was defined at the Prati di Stuores/Stuores Wiesen section, Italy (South Alps), the GSSPs of the Carnian/Norian and Norian/Rhaetian boundaries have not yet been ratified. The candidate sections of the inter-stages boundaries of Upper Triassic are all located in western Tethys or northern America. The major problem for definition for these boundaries maybe caused by the reliance on ammonoid-based biostratigraphy for Upper Triassic chronostratigraphic definitions. The native ammonoid marker species in western Tethys are rarely found in other regions. High-resolution conodont biostratigraphy has the advantage for making the Upper Triassic inter-regional or global correlation because some of Late Triassic conodonts were cosmopolitian species. At the other hand, magnetostratigraphy is a significant multi-chronostratigraphies, and needs vast improvement to make a serious contribution to the Triassic timescale. It will help us to conduct inter-regional calibration in China and Europe and to other reference sections used for the Triassic global time scale.. There was a significant climate changes in the mid-Carnian. It was firstly reported in west Tethys, and known as the Carnian Humid Episode (CHE) or Carnian Pluvial Event. CHE was associated with biotic changes like the disappearance of carbonate deposits, the decline of crinoids, ammonites, echinoids etc. Recently, few works confirmed the CHE also occurred in eastern Tethys (South China). It implies that CHE was a more widespread and probably global climate perturbation. .In Southern China, there develop good records of marine Upper Triassic. It is an ideal area to understand the biotic and environmental changes during Late Triassic. Unfortunately, both conodont fauna and stratigraphy were received less study during the past. This project aims to reveal the conodont evolution and biotic-environmental changes.Based on processing big conodont samples, this project will conduct high-resolution conodont biostratigrphy at selected sections in Guizhou, Yunan, Sichuan and Tibet etc.. We will also make magnetostratigraphic study at several fossil-rich sections in Southern China. By analysis of conodont apatite oxygen isotope, we will reconstruct the sea water palaeotemperature in Southern China during the Late Triassic. Incorporating conodont oxygen isotope and sedimentlogical study, we will check if the CHE widespread in Southern China and its impact on environments and organisms. Based on the high resolution conodont stratigraphy and magnetostratigraphy, this project will engage in the correlation of Upper Triassic between eastern and western Tethys. Undoubtedly, this work will greatly enrich our knowledge on conodont evolution and biotic-environmental events in Southern China, improve the research of the Upper Triassic chronostratigraphy, make contribution to Global Upper Triassic Geological Time Scale.