柴达木盆地北缘超高压变质岩的围岩长英质片麻岩锆石LA—ICP—MS定年

收稿日期: 2005-05-25

修回日期: 2005-08-22

刊出日期: 2006-01-15

LA-ICP-MS zircon U-Pb dating of quartzo-feidspathic gneisses--the country rocks of ultrahigh-pressure metamorphic rocks on the northern margin of the Qaidam basin, Northwest China

Received Date: 25 May 2005

Revised Date: 22 August 2005

Publish Date: 15 January 2006

摘要: 柴达木盆地北缘大柴旦地区超高压变质岩的围岩--长英质片麻岩的主要矿物组合为石榴子石+蓝晶石+多硅白云母+条纹长石+石英+斜长石,形成压力在800MPa以上.在阴极发光图像内部结构研究的基础上,利用LA-ICP-MS对该长英质片麻岩中锆石的变质微区进行了详细的原位微区U-Pb定年,得到206Pb.238U加权平均年龄为427.2 Ma±4.5 Ma,对应的Th/U为0.01～0.06.该年龄与本区已有的榴辉岩的围岩超高压泥质片麻岩、石榴子石橄榄岩的变质年龄在误差范围内一致.
- 柴达木盆地北缘长英质片麻岩 LA—ICP—MS U—Pb定年锆石
- northern margin of the Qaidam basin; LA-ICP-MS U-Pb dating; quartzo-feldspathic gneiss; zircon