摘要
扬子地台西缘康滇裂谷盆地内南北向断续分布的苏雄组是新元古代伸展作用下的岩浆活动产物,不整合伏于青白口纪地层体之上而伏于南华系上统列古六组之下。通过对米易白坡山一带苏雄组的调查,其火山岩具有钙碱性-碱性、过铝质特征,属钾钠过渡系列,稀土总量不高,轻重稀土分异作用强,δEu负异常明显,大离子亲石元素及高场强元素普遍亏损,不相容元素普遍富集的特征;上部火山岩705.6±9.3Ma的LA-ICPMS锆石U-Pb同位素年龄,晚于扬子西缘A型花岗岩年龄,大致约束了康滇裂谷盆地的关闭时间。
The Neoproterozoic Suxiong Formation intermittently exposed in the Kangdian rift basin resulted from magmatism under extensional condition.It overlies unconformably on the Qingbaikouan System and underlies the Liegulu Formation of the Upper Nanhua System.The Suxiong Formation in Baiposhan,Miyi is composed of calc-alkali to alkaline and peraluminous volcanic rock characterized by low ΣREE,strong HREE-LREE differentiation and obvious negative δEu anomaly,depletion in LILE and HFSE high field strong element and enrichment in incompatible elements.The upper volcanic rock yields zircon U-Pb ages of 705.6±9.3 Ma which are later those of A-type granite on the western margin of the Yangtze Platform.These age values restrain closure time of the Kangdian rift basin.
作者
骆志红
罗林洪
邓红
贾志泉
谢长江
LUO Zhi-hong;LUO Lin-hong;DENG Hong;JIA Zhi-quan;XIE Chang-jiang(College of Earth Sciences,Chengdu University of Technology,Chengdu 610059;No.108 Geological Team,BGEEMRSP,Chengdu 611230)
出处
《四川地质学报》
2019年第1期3-6,共4页
Acta Geologica Sichuan
基金
中国地质调查局四川攀枝花地区1:5万新坪-麻陇五幅区域地质矿产调查项目(1212011220395)资助
关键词
苏雄组
岩石地球化学
陆内裂谷
米易
Suxiong Formation
petrogeochemistry
intercontinental rift
Miyi
