生物相及其分区的研究对于川西地区中二叠世—中三叠世的古生物古地理、古板块等特征的恢复具有一定的参考意义。研究区内二叠系—三叠系生物化石丰富,其门类主要有腕足类、珊瑚、蜓类、菊石、牙形石、头足类、双壳类及有孔虫等。研究表明,这些生物门类的分布受沉积环境控制较为明显。在对生物群落划分和研究基础上,根据其与沉积特征的组合规律,在研究区识别出6种类型的生物相。通过对生物的生态类型、产出岩性以及对应沉积相类型等分析的基础上,建立了研究区中二叠世—中三叠世生物相模式,并详细阐述了各类型生物相中的生物类别以及典型群落等特征和含油性特征。根据生物的生态、地理分布特征及生物相在时间和空间上的组合规律,将川西地区中二叠世—中三叠世划分为3个生物相区,认为台地生物相区受控于扬子台地的发展,盆地生物相区受控于龙门—松潘海槽的发育。生物相类型的分布特征表明,台地型和缓坡型生物相主要分布于研究区的主体区域,体现了其分布主要受控于扬子台地,而深水盆地型生物相则主要分布于研究区边缘区域,反映出其分布主要受控于其北部的龙门海槽。

： The research area is located in the western part of Sichuan basin as a Yangtze ecotope of Cathaysian Tethyan area. It is dominated by benthic fauna, including brachiopods, Fusulinids, corals, bivalves, foraminifers, ammonites, bryozoans, Crinoids and pleopods are less common with traces of trilobites, stromatoporas, nautilus and sporopollens seen in one or two areas,which are obviously controlled by sedimentary environments in accordance with sedimentary facies. On the basis of division and research of biological communities and according to the combination of communities with sedimentary characteristics, six kinds of biofacies have been recognized and described in the study area,i.e. benthic biofacies of restricted platform, benthic biofacies of open platform, benthic biofacies of inner gentle slope, benthic biofacies of outer gentle slope, benthic biofacies of shelf slope and swimming biofacies of deep-water basin. Based on the study of middle Permian to middle Triassic biofacies,biofacies pattern are established, category, ecotype, typical community , sedimentary facies and oilbearing of each biofacies are elucidated in this paper. According to the association law of biofacies in time and space, the ahthors think that there are three biofacies provinces in the study area, i.e., platform biofacies province, slope biofacies province and basin biofacies province.The distribution characteristics of bioface types indicates that the platform-type and ramp-type biofacies are mainly distributed in the subject of the study area. It indicates that their distribution are mainly controlled by Yangtze platform. But the bioface of deep water basin type biofacies and basin biofacies province are mainly distributed at the edge of study area, indicating that they are mainly controlled by the Longmen trough. The study of biofacies and their provincialization of Middle Permain-Middle Triassic in the Western Sichuan Basin is a reference for the reconstruction of paleogeography and paleo-plate.Therefore, the research is meaningful for the analysis of paleogeography, tectonics and their evoulution of the Sichuan Basin.