福山凹陷流沙港期源区构造环境、母岩类型及演化

通过对福山凹陷流沙港组砂岩碎屑组成及Dickinson三角图解分析,揭示了源区主要为稳定成熟陆块的混合造山带,火山弧造山带、碰撞缝合线及褶皱—逆掩带也有一定的贡献,与海南岛以外来峰的方式逆冲—推覆在不同岩片之上形成的岩片叠置堆垛系统的构造背景相吻合。利用Q型和R型聚类划分出源区及不同源区的重矿物组合,结合重矿物含量、形态、构造、岩屑成分及石英阴极发光特征等,认为源区母岩存在10类岩性组合。根据ZTR指数变化趋势及重矿物组合,研究区主要发育云龙凸起和海南隆起两个物源,海南隆起可划分多文—龙波及澄迈两个相对独立的物源。流三段沉积时,美台、花场及白莲地区分别接受来自多文—龙波、迈澄及云龙凸起沉积物,母岩主要为中酸性岩浆岩及变质岩,迈澄源区母岩缺乏变质岩；流二段沉积时,花东及白莲地区接受来自云龙凸起沉积物,母岩为中酸性岩浆岩及沉积岩；流一段沉积时,H7-2井区至永安一带主要由迈澄提供物源,母岩为中酸性岩浆岩、沉积岩及变质岩,H8井区受到澄迈、云龙凸起物源共同影响。

Tectonic Environment,Parent Rock Type and Evolution of Source Area in Liushagang Period,Fushan Sag,Hainan

Through the analysis of sandstone clastic composition and Dickinson triangle diagram of Liushagang Formation in Fushan Sag, it is revealed that the source area is mainly a mixed orogenic belt of stable mature continental blocks, and the volcanic arc orogenic belt, collision suture and fold overthrust belt also contribute to a certain extent, It is consistent with the tectonic setting of the superimposed stacking system of rock sheets formed by thrusting and napping on different rock sheets in the form of external peaks in Hainan Island. According to the Q-type and R-type clustering, the heavy mineral assemblages in the source area and different source areas are divided. Combined with the heavy mineral content, morphology, structure, cuttings composition and quartz cathodoluminescence characteristics, it is considered that there are 10 types of lithologic assemblages in the source rock. According to the variation trend of ZTR index and heavy mineral assemblage, Yunlong uplift and Hainan uplift are mainly developed in the study area. Hainan uplift can be divided into two relatively independent provenances, Duowen-Longbo and Chengmai. During the deposition of the third member of Liuzhou Formation, Meitai, Huachang and Bailian areas received sediments from Duowen-Longbo, Maicheng and Yunlong uplift respectively. The parent rocks were mainly intermediate acid magmatic rocks and metamorphic rocks, while the parent rocks in Maicheng source area lacked metamorphic rocks； During the deposition of the second member of Liushagang Formation, Huadong and Bailian areas received sediments from Yunlong uplift, and the parent rocks were intermediate acid magmatic rocks and sedimentary rocks； During the deposition of the first member of Liushagang Formation, the provenance from well H7-2 to Yong'an is mainly provided by Maicheng, and the parent rock is intermediate acid magmatic rock, sedimentary rock and metamorphic rock. The provenance of well H8 is jointly affected by Chengmai and Yunlong uplift.