西藏得明顶地区叶巴组火山岩地球化学特征和同位素U-Pb年龄证据Evidences from Geochemistry and Zircon U-Pb Geochronology of Volcanic Rocks of Yeba Formation in Demingding Area,the East of Middle Gangdise,Tibet
陈炜;马昌前;边秋娟;胡远清;龙桃成;喻水林;陈冬明;屠江海;
摘要(Abstract):
对西藏得明顶地区叶巴组英安岩进行了锆石SHRIMP的U-Pb测年,获得(192.7±1.3)Ma的年龄值可代表得明顶地区叶巴组的年龄,其形成时代为早侏罗世,与达孜县地区叶巴组火山岩近同期。地质年代学研究和岩石组合特征显示,得明顶地区的叶巴组岩性主要为一套浅变质安山岩、英安岩、流纹岩、酸性凝灰岩夹少量碎屑岩、碳酸盐岩,可分为上、中、下3部分。地球化学特征显示,叶巴组为一套中酸性火山岩,可能是雅鲁藏布江洋向北俯冲、消减的产物,形成于岛弧环境。
关键词(KeyWords): 早侏罗世;叶巴组;火山岩;年龄;得明顶;西藏
基金项目(Foundation): 中国地质调查局矿产资源补偿费矿产勘查项目(矿调[2005]1-10]
作者(Author): 陈炜;马昌前;边秋娟;胡远清;龙桃成;喻水林;陈冬明;屠江海;
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