扬子北缘晋宁期望江山基性岩体的地球化学特征及其构造背景  

Geochemical Features and Its Tectonic Implication of the Jinningian Wangjiangshan Gabbros in the North Margin of Yangtze Block

作　　者：凌文黎[1] 王歆华[1] 程建萍[1] 

机构地区：[1]中国地质大学岩石圈构造,深部过程及探测技术教育部重点实验室,湖北武汉430074

出　　处：《矿物岩石地球化学通报》2001年第4期218-221,共4页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金 ( 4 98730 10 ;497940 43);国土资源部科技基金 ( 2 0 0 0 10 10 2 0 3);西北大学大陆动力学教育部重点实验室基金资助项目

摘　　要：钐 钕同位素定年和系统的元素 同位素地球化学研究表明 ,位于扬子克拉通北缘的望江山基性岩体形成于约 785± 88Ma的晋宁期 ,并具有陆内裂谷环境岩浆作用的地球化学属性 ,与时代为 0 95～ 0 .90Ga、具岛弧型火山岩特征的西乡群明显不同 ,标志该地区于新元古代经历了由洋壳消减的大陆边缘向陆内裂谷转变的构造演化。A comprehensive study of geochemistry has made on the Wanjiangshan gabbros of the Jinniang (Neoproterozoic) in the north margin of the Yangtze block.The affinities to continental rift for the formation environment of gabbros rather than plate subduction, which was proposed by some researchers, are displayed by a series of geochemical characteristics. Sm-Nd radiometric dated age of 785±88*!Ma for the gabbro further refers the scenario that a rift event was developed in the later Jinning after an early regional tectonic setting of oceanic crust subduction during 0.95～0.90 Ga along the north margin of Yangtze block.

关 键 词：扬子克拉通北缘 望江山岩体 晋宁期 地球化学 构造背景 

分 类 号：P588.124[天文地球—岩石学]