辽东地区早元古代火山岩特征及其形成的动力学背景  

Characteristics of the Early Proterozoic Volcanic Rocks and Its Dynamic Background of Formation in the Liaodong Area

作　　者：王艺芬[1] 徐贵忠[1] 佘宏全[2] 石铁铮[3] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]中国地质科学院矿产资源研究所,北京100037 [3]东北大学资源与土木工程学院,辽宁沈阳110004

出　　处：《现代地质》2005年第3期315-324,共10页Geoscience

基　　金：中国科学院重点项目(KZ952-J1-057)。

摘　　要：辽东地区早元古代火山岩是下元古界辽河群地层的重要组成部分,它们由酸性和基性两套火山岩组成。前者形成于辽河裂谷发育早期的拉张裂陷阶段,属于壳源岩浆成因;后者形成于辽河裂谷发育中晚期的强烈拉张裂陷阶段,属于幔源岩浆成因。重点讨论了基性火山岩的岩石学、矿物学、岩石化学和地球化学特征,结果表明,这些基性火山岩主要为一套海底喷发的基性枕状熔岩,具有大陆拉斑玄武岩和大洋拉斑玄武岩的双重特征,是辽河裂谷由大陆壳向大洋壳演化过程中的产物。火山岩形成的动力学背景与早元古代时期热地幔对流形式的出现以及郯—庐断裂带发生右旋平移剪切活动密切相关。The Early Proterozoic volcanic rocks of the Liaodong area are the important part of composition of Lower Proterozoic Liaohe Group. They are composed of two suites of the acid and basic volcanic rocks. It is suggested that the former should have been formed during the early-tensile depressing stage of the Liaohe rift development, which belongs to the melted crustal magma; the latter should have been formed during the mid-late intensive depressing stage of the Liaohe rift, which belongs to mantle-derived magma. This paper deals mainly with the characteristics of the petrology, mineralogy, petrochemistry and geochemistry for the basic volcanics. The above result has indicated that these volcanic rocks are mainly a suite of eruptive pillow basic lava from the sea-floor, which have the characteristics of the continental and oceanic tholeiites and belong to the evolutionary products of the Liaohe rift from continental crust to oceanic crust. It is thought that the dynamic background of the formation for volcanic rocks is closely related to the occurrence of the hot-mantle convection and the translational activity of the right-lateral shear of the Tan-Lu fault zone during the Early Proterozoic Era.

关 键 词：辽河群 基性火山岩 动力学背景 早元古代 辽东地区 

分 类 号：P588.1[天文地球—岩石学]