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受多期岩溶叠合改造影响,鄂尔多斯盆地东北部奥陶系马五_(1+2)亚段的原岩组构遭受破坏,制约了对原始沉积环境及沉积相的恢复研究。基于岩芯、薄片及阴极发光研究,通过原岩组构恢复,在区内识别出5种主要的原始碳酸盐岩类型及7种成岩作用产物岩石类型,并总结出5种岩石类型组合,分别形成于局限—蒸发台地内的颗粒滩、滩间海、丘滩复合体、台坪和局限瀉湖沉积环境。纵向上可构成局限瀉湖—颗粒滩—台坪、局限瀉湖—丘滩复合体—台坪等4种典型的向上变浅沉积序列。结果表明,颗粒岩类与含膏模孔泥(粉)晶云岩类是盆地东北部马五_(1+2)亚段最主要的原始岩类,并发育有一定规模的藻黏结岩和泥晶云岩,其中含膏模孔泥(粉)晶云岩与丘、滩向上变浅序列密切相关。这些认识将为深化区内古环境和储集岩类研究提供依据。
Under the influence of multi-stage karstification, the original rock structure of the Ordovician Ma5 (1 +2) sub-member in the northeastern Ordos Basin is damaged, which restricts the restoration of the original sedimentary environment and sedimentary facies. Based on the core, flake and cathodoluminescence studies, five primary types of carbonate rocks and seven types of diagenesis rock types were identified in the area through the restoration of the original rock structure. Five types of rock assemblages were concluded, Respectively formed in the limited - evaporating platform within the pellet beach, the beach between the sea, beach complex, terrace and confined lagoon sedimentary environment. Four types of typical upward-shallowing sedimentary sequences, such as confined lagoon-granite beach-terrace, confined lagoon-mound beach complex-terrace, can be formed longitudinally. The results show that the granitic rocks and the plaster-containing mud (dolomite) dolomite are the most important primitive rocks in the Ma5_ (1 +2) sub-zone in the northeastern part of the basin, and the development of algal cement with a certain scale Mud crystal dolomite, which contains the paste mold hole mud (powder) crystal and mound, beach lit up sequence is closely related. These understandings will provide the basis for deepening the paleoenvironment and reservoir rock research in the area.