塔里木盆地下奥陶统与上覆地层间的不整合

Unconformity between Lower Ordovician and Overlying Strata in Tarim Basin

关于塔里木盆地奥陶系内部不整合的地质时代和规模,存在着不同的观点。塔里木盆地奥陶系最主要的油气勘探目的层是鹰山组,但至今仍把鹰山组归属于中—下奥陶统,即认为塔里木盆地奥陶系内部关键不整合是中—下奥陶统与上覆地层之间的不整合。根据牙形石化石,塔里木盆地奥陶系内部规模最大的不整合是从早奥陶世后期开始的,该不整合遍及整个盆地,在台地相区存在于鹰山组与其上覆地层之间,在斜坡相区存在于库鲁克塔格露头剖面巷古勒塔格组内部。

There are different views on the geological ages and scales of the unconformities within the Ordovician strata in Tarim basin.The Yingshan formation is the key hydrocarbon exploration target in the Ordovician strata of Tarim basin,but up to now,researchers still consider that the Yingshan formation should be classified into the Middle-Lower Ordovician,so the unconformity within the Ordovician strata should be the unconformity between the Middle-Lower Ordovician and the overlying strata in Tarim basin.Based on the study of con?odont fossils,the author considers that the largest unconformity within the Ordovician strata in Tarim basin initiated from the late of Early Ordovician and is widely distributed across the basin,which exists between the Yingshan formation and the overlying strata in platform ar?ea and is found within Xiangguletage formation in the profile of Kuluketage outcrop in the slope area.