摘要
鄂尔多斯盆地东南部三叠系延长组一段湖相浊积岩主要分布于子长县寺湾和横山县庙沟等地区,位于长一段上部。岩石类型包括:块状砂岩,近基的中细粒砂岩,远基的粉砂岩及细砂岩,不规则砂、泥岩互层和深湖相泥岩。据岩石组合类型将该浊积扇划分为上扇和中扇,其沉积序列为向上粒度变粗、砂层变厚的进积型浊积扇沉积序列。根据底部印模构造指向,物源区大致位于研究区的北东。本文总结了浊积扇的演化,探讨了该浊积扇的发现对于认识区域构造背景及油气勘探的意义。
The lacustrine turbidite in the Member 1 of Yanchang Formation in age of Late Triassic was located in the upper part of Upper Triassic and distributed mainly in Siwan,Zichang county, and Miaogou, Hengshan county, namely, the southeastern part of the Ordos Basin. The turbiditic lithofacies included massive sandstones, proximal middle-fine grained sandstones, distal fine grained sandstone and siltstone, irregular alternating beds of sandstone and mudstone, and deep lacustrine mudstone. The turbiditic fan could be divided, according to the lithological associations, into two sub-facies：upper fan and middle fan. The sedimentary succession indicated that the turbidity fan should be a prograded one, featured with sand layer thickening and grainsize coarsing upwards. The provenance for the turbidite might be located to the northeast of the studied area,evidenced by the vector structures such as sole cast structure in the turbidite. Based on what mentioned above,combined with other proofs of deep water sediments, the paper summarized the turbiditic evolution and discussed the significances of the discovery for understanding the regional tectonic setting and the potentials of oil-gas exploration.
出处
《地质科学》
CAS
CSCD
北大核心
2006年第1期54-63,I0003,共11页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
国家重点基础研究发展计划项目(2003CB214602)
陕西省自然科学基金项目(2003D14)资助。
关键词
湖相浊积岩
包马序列
鄂尔多斯盆地
三叠系延长组一段
Lacustrine turbidite, Bouma Sequence, The Ordos Basin,the Member 1 of Yanchang Formation, Upper Triassic
