渤中凹陷19-6区太古界潜山变质岩岩石类型及鉴别特征

Types and identification characteristics of Archean metamorphic rocks of Buried Hill in 19-6 area of Bozhong sag

渤中凹陷19-6区域现有钻井揭示,研究区太古界潜山变质岩岩石类型主要有区域变质岩和动力变质岩2类,常见的7种岩性为变质花岗闪长岩、变质二长花岗岩、花岗闪长质片麻岩、碎裂变质花岗闪长岩、碎裂变质二长花岗岩、长英质碎斑岩和花岗闪长质初糜棱岩。笔者从岩石矿物成分及组合、结构构造等方面详细描述了这7种变质岩及其鉴别特征,在此基础上研究几种变质岩与裂缝之间的关系,结果表明其中的变质二长花岗岩与花岗闪长质片麻岩裂缝密度相差> 2倍,研究显示不同岩石矿物成分尤其是暗色矿物的含量与岩石产生裂缝能力有关。

Existing drilling in the 19-6 area of Bozhong sag reveals that there are mainly two types of metamorphic rocks in the Archean Buried Hill metamorphic rocks in the study area:regional metamorphic rocks and dynamic metamorphic rocks.The metamorphic rocks comprise metamorphic granodiorite,metamorphic monzogranite,granodioritic gneiss,cataclastic metamorphic granodiorite,cataclastic metamorphic monzogranite,felsic porphyroclasite and granodioritic protomylonite.The authors describe the identification characteristics of seven metamorphic rock types in detail from the aspects of mineral composition and assemblage,texture and structure,and discuss the relationship between rock types and fractures.The fracture density of metamorphic monzogranite is as twice high as that of granodiorite gneiss,indicating that the content of different rock minerals,especially dark minerals,affects the ability of rocks to produce fractures.