滇西龙陵-瑞丽断裂带早白垩世火山岩LA-ICP-MS锆石U-Pb定年和地球化学特征  

LA-ICP-MS zircon U-Pb dating and geochemical characteristics of Early Cretaceous volcanic rocks in Longling-Ruili fault belt,western Yunnan Province

作　　者：白宪洲[1,2] 贾小川[2] 杨学俊[2] 熊昌利[2] 梁斌[3] 黄柏鑫[1,2] 罗改[2] 

机构地区：[1]成都理工大学核技术与自动化工程学院,四川成都610059 [2]四川省地质调查院,四川成都610081 [3]西南科技大学环境与资源学院,四川绵阳621000

出　　处：《地质通报》2012年第2期297-305,共9页Geological Bulletin of China

基　　金：中国地质调查局国土资源大调查项目<1:5万清河街幅等4幅区调联测>(编号:1212010784006);<泛亚铁路大理至瑞丽沿线地质构造综合研究>(编号:1212010814054);基本科研业务费项目<成果集成与战略研究>(编号:DZLXJK201113)

摘　　要：通过对龙陵-瑞丽断裂与主高黎贡断裂夹持区内构造混杂岩进行地质填图和剖面研究,在原划的三叠纪扎多组中发现沿龙陵-瑞丽断裂带呈透镜状断续分布的中酸性火山岩,并获得LA-ICP-MS锆石U-Pb年龄130.0Ma±1.7Ma,首次证实滇西龙陵-瑞丽断裂带存在早白垩世火山岩。结合岩石学特征和地球化学特征判断该火山岩形成于岛弧环境,可能是早白垩世怒江洋闭合过程中岩浆活动的产物。Based on a study of the tectonic mélange between the Longling-Ruili fault and the main Gaoligong fault with the help of geological mapping and sections,the authors found the lentoid and intermittent medium-acidic volcanic rocks,which belong to the Triassic Zhaduo Formation and lie in Longling-Ruili fault.The zircon U-Pb dating age of 130.0±1.7Ma of the volcanic rocks was obtained.It is confirmed for the first time that there exist early Cretaceous volcanic rocks in the Longling-Ruili fault of western Yunnan Province.The geochemical characteristics of the volcanic rocks suggest that they were island arc tholeiites（IAT）and should be the response to the closure of the Nujiang ocean in the Early Cretaceous,related to westward subduction of Bangong Co-Nujiang oceanic crust and eastward subduction of Neo-Tethys oceanic crust.

关 键 词：滇西 龙陵-瑞丽断裂带 火山岩 早白垩世 LA-ICP-MS锆石U-PB测年 

分 类 号：P597.3[天文地球—地球化学]