黔西南中三叠统坡段组石珊瑚动物群研究

The Middle Triassic scleractinian coral Lagerstatten in southwestern Guizhou is one of the best-preserved and most abundant early coral Lagerstatten in the world. It is an early sign of the emergence of the scleractinian coral after the P-T mass extinction. Some scleractinian coral fossils have been recently found in this area, including Pamiroseris silesiaca, Eckastraea prisca, and Pentasmilia guangxiensis. On the basis of conodonts and ammonoids in the same horizon, it is here inferred that the oldest scleractinian coral fossils are likely to be found in this area. The Paravolzeia alpina (type species of Paravolzeia in the Triassic) found in this layer, has been found to match Numidaiphyllum gillianum (type species of Numidaiphyllum in the Permian) in external morphological features, internal skeletal structure and reproduction type, which provides important scientific information for exploring the origin and evolution of the scleractinian coral. In addition, a patch reef whose structure was principally built by scleractinian corals has been found in the Zhenfeng area, which maybe provide strong evidence that scleractinian corals served as primary reef-builders as early as the late Anisian. Therefore, this project plans to explore this area further, to gain more fossil data, analyze the classification, composition and distribution of the coral fauna, determine its geology age, revise some confusing taxa, identify new genera, and further establish the environmental characteristics of this recovery period. The project results will greatly complement existing diversity data regarding the world's earliest scleractinian coral, improve the systematic categorization of the Triassic scleractinian corals, provide new evidence regarding the origin of the scleractinian coral, and provide an important foundation for further exploration of the environmental changes that have taken place since the Mesozoic.

黔西南中三叠统石珊瑚化石库是世界上早期石珊瑚保存最好、最丰富的化石库之一，是P-T生物大绝灭事件后石珊瑚出现的早期标志。申请人近期在该地区发现一些石珊瑚化石，依据同层位牙形石和菊石资料，初步推断可能发现目前最古老的石珊瑚化石。同时，在该层位发现的Paravolzeia模式种，其外部形态特征、内部骨骼构造以及繁殖方式，均与二叠纪Numidaiphyllum模式种相似，这对探讨石珊瑚起源及演化具有重要的科学价值。此外，在贞丰地区发现一处以石珊瑚为主要造架生物的点礁，这或许为石珊瑚在安尼晚期即作为主要造礁生物参与造礁提供有力证据。因此本项目计划以黔西南中三叠统坡段组石珊瑚动物群为研究对象，开展进一步工作，寻找更多化石资料，分析其属种组合特征及地层分布情况，确定其地质时代，并进一步恢复复苏期环境特征。项目成果将极大补充世界最早期石珊瑚多样性资料，并为探索石珊瑚起源和中生代以来环境变化提供重要依据。

石珊瑚在二叠纪末生物大灭绝之后突然出现并迅速扩张，是中-新生代海洋生物的重要门类，也是中生代初期现代型海洋生态系重建的重要组分，但至今其背后的驱动机制仍不清楚。本项目以扬子地台西南缘中生代初期石珊瑚动物群为研究对象，选择研究区中三叠世地层连续沉积的坡段组等礁滩相沉积地层，对其中保存的中三叠世石珊瑚化石进行系统古生物学研究，根据地球化学数据及其上下层位牙形石数据确定了该地区保存有目前世界上最早期的石珊瑚化石动物群；并确定了该石珊瑚动物群属种及组合特征；结合其骨骼微细构造的研究探讨了中生代初期石珊瑚的起源问题；并对该区石珊瑚动物群在中生代初期的地层分布规律和多样性演化开展了研究。项目成果将进一步补充丰富世界上最早期石珊瑚研究的资料；并为探索中新生代石珊瑚的起源和演化提供有力证据。