【摘要】 麻扎地区弧火成岩是1∶25万麻扎幅区域地质调查过程中发现并厘定的,位于麻扎构造混杂岩带之中,包含着古洋壳消减过程中的一些重要信息。弧火成岩主要由中酸性侵入岩和火山岩组成,具岛弧性质的岩石组合和岩石地球化学特征。对弧火成岩中的角闪石英闪长岩进行锆石SHRIMPU-Pb测年,结果为338Ma±10Ma,时代为早石炭世。麻扎地区弧火成岩的发现,不但证明了在晚古生代出现过麻扎-康西瓦洋(古特提斯),而且说明该洋在石炭纪已经开始俯冲-消减。更多还原

【Abstract】 Arc magmatic rocks in the Mazar area was discovered and defined during the 1∶250000 regional geological survey of the Mazar Sheet. The arc magmatic rocks in the Mazar tectonic mélange zone contain some important information of the consumption process of old oceanic crust. The arc magmatic rocks are dominantly composed of intermediate-acid intrusive rocks and volcanic rocks and have island arc rock associations and geochemical affinities. Zircon SHRIMP U-Pb dating of hornblende-quartz diorite in the arc magmatic rocks yielded an age of 338±10Ma, indicating an Early Carboniferous age. The discovery of the arc magmatic rocks in the Mazar area has not only supported the idea of the appearance of the Mazar-Kangxiwar ocean (Paleo-Tethys) in the Late Paleozoic, but also suggested that this ocean had begun subduction and consumption by the Carboniferous.更多还原