地质与勘探2012，Vol.48Issue(4)：790-798,9.
新疆金窝子片麻状花岗岩锆石U-Pb年代学、地球化学特征及其地质意义
Zircon U-Pb Dating and Geochemical Characteristics of the Gneissic Granite in the Jinwozi Gold Deposit,Xinjiang and Their Geological Implications
摘要
Abstract
The Jinwozi gold deposit is one of the important gold deposits in eastern Xinjiang.It is hosted in the volcaniclastic-sedimentary rocks of the upper Devonian Jinwozi Formation and the Jinwozi gneissic granite.Previous studies suggest that the Jinwozi gneissic granite formed at 356 ~ 392 Ma.This large time variation does not accord with the geological information that there is gneissic granite gravel in the bottom of the Jinwozi Formation.This conclusion,to some extent,limits the further study on the gold mineralization and geological background in this area.Accurate age determination of the Jinwozi gneissic granite is critical for researching gold mineralization and tectno-magmatic evolution.In this work,U-Pb dating and Hf isotope studies of zircon grains from the Jinwozi gneissic granite have been conducted by the high-precision LA-ICP-MS method.The result shows that the gneissic granite magma crystallization age is 429.1 ± 2.7Ma,in the middle Silurian.The εHf（t） values of Zircon and Hf two-stage isotope model ages are-3.5-＋1.2 and 2545~3072 Ma,respectively.Geochemical data of granite demonstrates that it is rich in LILE and depleted in HFSE（Nb,Ta,Ti）.A/CNK ranges from 1.13 to 1.14,which has the characteristics of high-K calc-alkaline volcanic rock series.It is thus concluded that the formation and emplacement of the Jinwozi gneissic granite are closely related to the closure of the South Tianshan ocean in the early Paleozoic and later collision of the Tarim plate with the Kazakhstan plate.关键词
锆石/LA-ICP-MS/定年/片麻状花岗岩/金窝子/新疆Key words
Zircon/LA-ICP-MS dating/gneissic granite/Jinwozi/Xinjiang分类
天文与地球科学引用本文复制引用
丛源,肖克炎,董庆吉,毛启贵..新疆金窝子片麻状花岗岩锆石U-Pb年代学、地球化学特征及其地质意义[J].地质与勘探,2012,48(4):790-798,9.基金项目
中国地质调查局地质大调查项目“全国重要矿产总量预测”（编号1212010633905）资助的成果 （）
