沉积与特提斯地质2017，Vol.37Issue(3)：96-102,7.
青藏高原羌塘中部双湖早古生代斜长角闪岩年代学及地质意义
The amphibolite from the Shuanghu region, Qiangtang Basin, Qinghai-Xizang Plateau: Geochronological and geological implications
摘要
Abstract
A succession of amphibolite crops out along the Qilongwuru valley in the Shuanghu region, Qiangtang Basin, Qinghai-Xizang Plateau. With the aid of SHRIMP zircon U-Pb dating, the amphibolite herein gives a 206 Pb/ 238 U weighted average age of 450. 1 ± 5. 0 Ma, indicating that the amphibolite was formed during the Late Ordovician. Geochemically, the amphibolite is characterized by SiO2 contents of 45. 67% -51. 68%, Na2 O contents of 0. 98%-2. 54%, high Na contents and lower K contents, lower differentiation of LREE and HREE, positive Eu anomaly, relatively enrichment of the elements Rb, Ba and U, and relatively depletion of the elements Nb, Ta and Zr. These geochemical signatures show that the amphibolite has the features of the enriched mid-oceanic ridge basalts ( E-MORB) , and represents the relicts of the Palaeo-Tethys oceanic crust. The similarity in the ages and geochemical signatures of the amphibolite from the Qilongwuru valley in the Shuanghu region and those of the Tongchang ophiolites and Wanhe ophiolites in the Changning-Menglian suture zone indicates that the Lungmuco-Shuanghu sutute zone and Changning-Menglian suture zone are represented by a unified Proto-( Palaeo-) Tethys ocean.关键词
龙木错-双湖结合带/昌宁-孟连结合带/双湖齐陇乌如沟/锆石U-Pb年龄/斜长角闪岩Key words
Lungmuco-Shuanghu sutute zone/Changning-Menglian suture zone/Qilongwuru valley in Shuanghu/zircon U-Pb dating/amphibolite分类
天文与地球科学引用本文复制引用
杨桂花,彭智敏,张璋,关俊雷..青藏高原羌塘中部双湖早古生代斜长角闪岩年代学及地质意义[J].沉积与特提斯地质,2017,37(3):96-102,7.基金项目
中国地质调查局项目(DD20160016)、自然科学基金项目(41303043) （DD20160016）
