北祁连地区中寒武世岩相古地理研究

Sedimentary facies and palaeogeography of northern Qilian area during the Middle Cambrian

现今地处造山带的北祁连地区在中寒武世时期拉张的构造背景下海域进一步拓宽。通过对北祁连地区中寒武统地层野外调查及室内分析研究,在"构造控盆、盆控相"的思路控制下,以沉积岩性、结构-构造、古生物组合等为基础,在优势相原则的指导下,共划分出浅海陆棚相、半深海相、深海盆地相3种沉积相类型。结合前人的研究资料,编制北祁连地区中寒武世的沉积构造格架及沉积盆地类型图,分析其空间配置关系。在此基础上,采用造山带岩相古地理编图方法,恢复与重建研究区的古地理面貌,编制相应的古地理图。

The sedimentary facies and palaeogeographic analysis in the present paper is based on the field and laboratory examination guided by the thoughts of ＂tectonic-controlled basin and basin-controlled facies ＂ in integration with lithology, textures and structures, and fossil assemblages. Three sedimentary facies are discriminated including neritic shelf,bathyal and abyssal-oceanic basin facies,followed by the reconstruction of the sedimentary facies and palaeogeographic map of northern Qilian area during the Middle Cambrian. The results of research in this study may provide a helpful approach to the sedimentary facies and palaeogeographic analysis for the orogenic zones.