鲁西地区古生界与太古宇接触面滑脱构造带构造岩特征

运用构造地质学理论,通过野外地质调查和室内显微构造分析,揭示了鲁西地区古生界与太古宇接触面滑脱构造带缓倾斜断层构造岩的宏观和微观特征,分析了其在深层油气勘探中的作用。露头研究表明,鲁西地区古生界与太古宇接触面滑脱带构造岩主要为碎裂岩,岩石发生强烈的破碎,角砾成分主要为上盘碳酸盐岩的碎块,伴有硅化、大理岩化、镜铁矿化、绿泥石化等动力变质作用,薄层构造岩中揉皱发育。方解石、长石、石英等变形矿物的显微构造特征显示出滑移双晶、拉长、定向排列、机械双晶和动态充结晶等特征,表明缓倾斜滑脱构造带上的构造变形属低温的脆性、塑性变形。覆盖区古生界滑脱带构造岩与露头区有相似的特征,且破碎的构造岩是油气有效的储集空间和场所。研究表明,古生界与太古宇沉积不整合面已转化为构造滑脱面,同时对深层潜山油气的勘探和开发具有重要意义。

Characteristic of Tectonite in Paleozoic-Archean Decollement Structural Belt in Luxi Area

The macro- and micro-feature of tectonite of Paleozoic-Archean decollement structural belt in Luxi (West Shandong) area is presented by means of structural geology, field geologic survey and lab microstructure analysis, including its effect on deep hydrocarbon exploration. The outcrop study shows that the tectonite is consisted of cataclastic rock with rubbles of carbonate rock, associated with dynamic metamorphisms of silification, marblezation, specularitization and chloritization. Crumpled structure is developed in the thin tectonite. The microstructures of calcite, spar and quartz show the microfeatures of gliding twins, mechanic twins and dynamic recrystallization, indicating that the structural deformation is brittle and plastic deformation with a low temperature. The tectonite of Paleozoic in areal coverage appears the similar characteristic with that in outcrop area, and its cataclastic structure serves as an effective space for oil-gas accumulation. The study shows that the unconformity between the Paleozoic and the Archean was reformed into a structural decollement surface, being of a great significance to the exploration and development of deep buried-hill petroleum reservoirs in this area.