地质通报Issue(11)：1702-1714,13.
藏北羌塘冈玛错地区望果山组火山岩地球化学特征及LA-ICP-MS锆石U-Pb年龄
Geochemistry and LA-ICP-MS zircon U-Pb age of volcanic rocks of Wangguoshan Formation in the Gangmar Co area of Qiangtang, Tibet
摘要
Abstract
A set of early carboniferous volcanic rocks has been found in the Gangmar Co area of Qiangtang for the first time. The volcanic rocks are composed of acidic to basic volcanic rocks (rhyolite, dacite, basaltic andesite, basalt and andesite) intercalated with pyroclastic rocks. The LA-ICP-MS zircon U-Pb ages of two samples (dacite and basaltic andesite) are 358.2Ma±1.2Ma and 350.5Ma± 1.4Ma, which indicates that the volcanic rocks formed in the early Carboniferous. Rock geochemical characteristics show that the A/CNK indexes are 0.62~1.08, with an average of 0.81, and Rittmann indexes (δ) are 1.04~2.67, with an average of 1.84. These volcanic rocks are characterized by high LILE (Th, U and Pb) and obvious depletion of HFSE (Nb, Ta and Ti). The geochemical compositions of volcanic rocks belong to the calc-alkaline island arc volcanic rocks. It is indicated that the Lungmu Co-Shuanghu-Lancang River Ocean entered into its subduction stage in the Early Carboniferous.关键词
青藏高原/早石炭世/岛弧火山岩/LA-ICP-MS锆石U-Pb年龄/地球化学Key words
Tibetan Plateau/Early Carboniferous/island-arc volcanic rock/LA-ICP-MS zircon U-Pb ages/geochemistry分类
天文与地球科学引用本文复制引用
江庆源,李才,解超明,王明,胡培远,吴浩,彭虎,陈景文..藏北羌塘冈玛错地区望果山组火山岩地球化学特征及LA-ICP-MS锆石U-Pb年龄[J].地质通报,2014,(11):1702-1714,13.基金项目
国家自然科学基金项目（批准号41272240、41072166）与中国地质调查局项目 （）
