西昆仑柳什塔格峰西侧火山岩的特征、时代及地质意义  

Composition,age and geological significance of the Liushitage volcanics in West Kunlun mountains.

作　　者：李博秦[1] 姚建新[1] 王炬川[2] 计文化[3] 韩芳林[2] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]陕西省地质调查院,咸阳712000 [3]中国地质调查局西安地质矿产研究所,西安710054

出　　处：《岩石学报》2007年第11期2801-2810,共10页Acta Petrologica Sinica

基　　金：中国地质调查局"1:25万伯力克幅区域地质调查"(编号:19991300009061);国家自然科学基金"西昆仑地区古生代混杂堆积碎屑岩地层的再研究"(编号:40572018);中国地质调查局"中国西北地区若干重要演化阶段地层格架建立与对比研究"(编号:1212010611702);"中-巴合作西构造结及邻区有关矿产和环境灾害地质背景的研究"(编号:1212010661312)项目资助。

摘　　要：在西昆仑麻扎-康西瓦-苏巴什结合带的柳什塔格一带发现了一套火山岩建造,主要由强蚀变玄武岩、绿帘阳起石岩、阳起石岩(原岩为玄武岩)组成,上覆少量深水沉积岩。火山岩的岩石地球化学特征表明其主要来源于富集地幔玄武岩浆,形成于洋岛环境,因此它是一个古结合带大洋洋壳的残留。采样作Rb-Sr等时线年龄分析,时代为震旦纪(563±48Ma),说明麻扎-康西瓦-苏巴什结合带所代表的洋盆在震旦纪就已经存在。这个发现对重新认识麻扎-康西瓦-苏巴什结合带的演化时限具有重要意义。A suit of volcanics formation was found near the Liushitage area, in west Kunlun. And the volcanics formation composed of strongly corroded basalt, epidote actinolitite, actinolitite, and is covered by deep water sedimentary rocks. The geochemistry characteristics of volcanic rocks indicate that this volcanics originated from basaltic magma of enrichment mantle, which was formed in oceanic island, therefore the volcanic rocks is an ocean relic block of Paleo- suture zone. Dating of this volcanic sample by Rb-Sr isotopes shows the epoch, getting the isochrone age of 563 48Ma, is Sinian. The dating shows that the ocean of Mazha-Kangxiwa-Subashi suture zone was formed in Sinian. This discovery has great implication for recognizing evolution history of the Mazha-Kangwaxi-Subashi suture zone.

关 键 词：西昆仑 柳什塔格 火山岩 组成 时代 地质意义 

分 类 号：P588.145[天文地球—岩石学]