辽东半岛早元古宙海相拉斑玄武岩特征及其意义

辽东半岛早元古宙北部辽河群中层状基性岩发育广泛,与上覆层状岩系呈沉积接触关系,并发现多处枕状熔岩。层状基性岩的岩石学、岩石化学和地球化学的研究结果表明,这些层状基性岩是辽河群早期沉降阶段的海相拉斑玄武岩。辽东半岛早元古宙海相拉斑玄武岩的发现,将改变对辽河群下亚群火山—沉积建造内涵的传统认识,表明其产出为大陆边缘或类似弧后盆地的大地构造环境。这将为重新认识和评价辽东半岛早元古宙金属矿床开拓新思路。

FEATURES AND SIGNIFICANCE OF MARINE THOLEIITE OF EARLY PROTEROZOIC IN LIAODONG PENINSULA

Beded basic rocks are extensively distributed in northern Liaohe Group of Early Proterozoic in Liaodong Peninsula;they have the relationship of sedimentary contact with overlying beded rocks and there are pillow lavas in many places.The result of study on petrology,lithochemistry and geochemistry shows that these rocks are marine tholeiite in the early depression stage of Liaohe Group.The discovery of marine tholeiite of Early Proterozoic in Liaodong Peninsula will change the traditional understanding to the connotation of volcano-sedimentary formation,Lower Subgroap of northern Liaohe Group,shows that (?)t was occured in the geotectonic environment of continental margin or similar back-arc basin;and opens up new thinking for understanding and evaluating mental deposits of Early Proterozoic in Liaodong Penin- sula.