豫西太原组碳酸盐岩微相类型及其沉积背景

Based on the detail measurement and description of the Lower Permian Taiyuan Formation exposed in Jiaozuo and Yuzhou areas in the western Henan Province, this paper mainly observed crystal structure, particles types and microfacies characteristics in the each layer of carbonatite by using polarized light microscope, and 4 types of crystal structure of carbonatite were found in this Formation, including micrite, fine powder crystal, coarse powder crystal and very fine crystal. Bioclasts are the chief particle types in the carbonatites. According to the characteristics of grain size, particles type and their abundance, biological assemblages and their paleoecology, 15 kinds of carbonatite microfacies may be recognized. Through the comprehensive analysis of depositional features, trace fossils and the composition characteristics of biodetritus in different microfacies, the 15 types of microfacies were explained to form in four facies belts, namely, the bay-lagoon (MF-1and MF-2), restricted platform (MF-3, MF-4, MF-5 and MF-6), shoal in the platform (MF-7) and open platform (MF-8, MF-9, MF-10, MF-11, MF-12, MF-13, MF-14 and MF-15). Thus the sedimentary environment model of the carbonatite microfacies types in the Taiyuan Formation was put foward.