西北地质2017，Vol.50Issue(4)：9-17,9.
中祁连苏里地区奥陶纪石英闪长岩地球化学特征及年代学意义
Geochemical Characteristics and Chronology Significance of Ordovician Quartz Diorite from Suli Area in Middle Qilian Mountains
摘要
Abstract
In Suli area,the Ordovieian quartz diorite has poor aluminum and high potassium (K2O＞NaO),which belongs to calc-alkaline series,with the characteristics of partial aluminium shoshonite series and obvious Ⅰ-type granite.Rare earth and trace elements characteristics show that a mantle material was involved in the material source of quartz diorite.The tectonic environment discrimination suggests that the quartz diorite belongs to the island arc granite formed before the plate collision.The zircon U-Pb isotopic age has been tested by LA-ICP-MS method,the obtained zircon 206pb/238 U weighted average age is (474 ±-2.9) Ma (MSWD =0.12),which limit the formation age of the quartz diorite era to early Ordovician,suggesting that the north Qilian Ocean experienced two-way expansion and subduction stage,while the southern Qilian continental subduction extrusion cause the mantle material upwelling andthe partial melting of continental crust.And then,the rock mass of quartz diorite was formed.The age determination of this rock mass provides a new evidence for the subduction era of the north Qilian Ocean.关键词
中祁连/奥陶纪/石英闪长岩/岛弧Key words
middle Qilian/Ordovician/quartz diorite/island arc分类
天文与地球科学引用本文复制引用
郑英,陈光庭,张小永,宋泰忠,梁坤先..中祁连苏里地区奥陶纪石英闪长岩地球化学特征及年代学意义[J].西北地质,2017,50(4):9-17,9.基金项目
国土资源大调查“青海天峻县苏里地区五幅1∶5万区调项目成果”(1212011140088) （1212011140088）
