东濮凹陷古近系沙河街组盐岩成因研究的进展、问题与展望

东濮凹陷古近系沙河街组盐岩成因的研究进展主要包括两方面：一方面是盐的沉积机理研究，主要有“深水成盐”和“浅水成盐”两种完全对立的观点。“深水成盐”论者主要依据沉积学、古生物学和构造地质学等方面的论据，认为其盐是在一定的水深条件下形成的，分层卤水是成盐的基本形式；“浅水成盐”论者主要依据沉积学的论据，认为其盐是湖水持续蒸发浓缩的结果。另一方面是盐岩物质来源的研究，主要有海水侵入来源、地下深部热卤水来源和地表径流来源3种观点。海水侵入来源论者的主要依据是古生物化石，而其他两种来源论者则主要依据地球化学分析和推测。分析了盐岩研究中存在的6个主要问题：“深水成盐”论者的卤水分层成盐模式对东濮凹陷还只是一种假说，“浅水成盐”论者的论据不够全面，两种成盐论者对同一现象的解释存在较大分歧，测试样品的数量、分布及测试结果是否具有代表性值得考虑，海相化石尚需进一步厘定，海侵通道尚不明确。提出可利用双扩散对流数值模拟、地球化学及沉积学的综合研究对东濮凹陷古近系沙河街组盐岩成因作进一步探讨。

Advances, problems and prospect in studies of origin of salt rocks of the Paleogene Shahejie Formation in Dongpu Sag

The research progress in the origin of salt rocks of the Shahejie Formation of Paleogene in Dongpu Sag has been summarized， which mainly includes two parts. One aspect is the studies on salt deposition mechanism， including two contrasting viewpoints “salt deposited in deep water” and “salt deposited in shallow water”. The former， mainly based on sedimentology， paleontology， structural geology， and so on， considers that the salt is deposited in a certain water depth， and the brine delamination is a basic form of salt sedimentation. In contrast, the latter， mainly based on sedimentology， considers that the salt is the result of continuous lake evaporation. The other aspect is the studies on the source of salt rocks， which includes seawater from marine transgression， deep subsurface hot brine and surface fresh water. The evidence for the former one includes paleontological fossils， and the other two are supported by geochemical analysis and inferation. There are six main problems in studies of origin of salt rocks in the Paleogene Shahejie Formation in Dongpu Sag. The brine delamination model is just a hypothesis in explaining salt sedimentation in the Dongpu Sag. The evidence of “salt deposited in shallow water” is not adequate. There are great differences in explaining the same phenomenon between the two viewpoints of salt formation. It is not clear whether the quantity， distribution and analytical results of the samples truly represent the features of salt rocks in the Dongpu Sag. The marine fossils should be further identified. The channels of marine transgression remain unclear. Finally， the authors put forward that three methods can be applied to research the origin of salt rock of the Paleogene Shahejie Formation in the Dongpu Sag， which include numerical simulation of double diffusive convection， geochemical analysis and sedimentological studies.