Abstract:

This paper makes a study of the mixed clasticcarbonate deposits widely distributed in the lower part of the 1st member of the Shahejie Formation, Huanghua Depression. Since there is little research on this kind of mixed deposits, it is hard to identify sedimentary facies, reservoir distribution, poolforming elements and their distribution patterns. Therefore, by examining sedimentary microfacies and based on the sequence stratigraphic framework of the study area, we made a comprehensive study of petrologic features, genetic types and evolutionary patterns of mixed clasticcarbonate deposits and the controlling effect of sequence stratigraphic framework on their distribution. According to this study, we recognize four types of mixed deposits: parent material mixing, mixing due to gradual facies change, insitu mixing and gravity flow mixing. The mixed deposits are highly developed in lowstand system tract, but poorly developed in highstand and transgression system tracts. The lower part of the 1^st member of the Shahejie Formation, Huanghua Depression, is a typical example of modern mixed clasticcarbonate deposits. Results from this study can provide thoughts and foundations for further exploration and development in the study area.

Key words:  , Key words：sequence stratigraphic framework, genetic type, evolutionary pattern, mixed clasticcarbonate deposit, Shahejie Formation, Huanghua Depression,Bohai Bay Basin