贵州晚二叠世—早三叠世介形虫动物群的演变

THE DEVELOPMENT OF THE LATE PERMIAN-EARLY TRIASSIC OSTRACOD FAUNA IN GUIZHOU PROVINCE

贵州有许多二叠系至三叠系的连续剖面,沉积类型多样,生物化石丰富,其中介形虫化石不但类型多,数量也很丰富,保存完好,发展阶段明显。即长兴阶介形虫类型多,数量也多,壳饰复杂,以具瘤刺的为多,早三叠世早期介形虫贫乏,数量及类型都不多,壳饰以光滑或具微细纹饰的为主。根据这些介形虫类型和数量的变化,以及壳饰特征的研究,表明二叠系与三叠系界线附近的介形虫动物群也同其它生物一样发生了重要变化。为二叠—三叠系界线的划分提供了依据。

In Guizhou Province of southern China, there are many marine Permian-Trias-sic continuous sections, in which sediment types are highly varied and fossils are abundant, of which Ostracod, fossils are numerous and perfectly preserved. These Ostracod fossils were taken from Zhenfeng, Zunyi, Qinglong and Anshun of Guizhou, including 28 genera and 70 species (Fig. 1).The Changxingian bears rich Ostracods of various types? this fauna contains 25 genera (Table 2). They are well preserved, and have perfect shell decorations. The main types of the shell decorations are spines and nodules on dorsal margins. The Early Triassic Ostracods are scarce and poorly preserved; this fauna contains 8 genera. The shells are smooth or have micro-ornamentations.The changes of the Ostracod abundance and morphology have revealed that Ostracods had a major faunal change near the Permian-Triassic boundary, which provides reliable biological evidence for the determination of the Permian-Triassic boundray in China.