地质学报2017，Vol.91Issue(7)：1433-1453,21.
南天山巴音布鲁克花岗岩岩体成因:锆石U-Pb定年、Hf同位素及其地球化学证据
Origin of Bayinbuluk Pluton in Southern Tianshan: Evidences from Zircon U-Pb Dating, Hf Isotope and Geochemistry
摘要
Abstract
Bayinbuluke pluton is one typical representative of granitic intrusions exposed in the northern margin of South Tianshan and composed mainly of monzogranite and K-feldspar granites.Both rocks are characterized by enrichment in Rb,Ba,Th,K and Sr,poor HFSE and depletion of Nb,Ta,Ti and P,geochemically similar to those of island magmatism occurred in active margins.Of them,monzogranite has relative low SiO2 and K2O,higher CaO,Fe2O3T and MgO,showing LREE-enriched and HREE depleted REE patterns with slightly negative Eu anomalies.Whereas K-feldspar granite has higher SiO2 and K2 O,lower CaO and MgO contents and strongly depleted in Sr,Ba,Eu,Ti and P,displaying medium LREEenriched and HREE-depleted REE patterns with strong negative Eu anomalies.Furthermore,both of them have higher DI (94.31～95.52) and Rb/Sr ratios.All suggests that it likely resulted from the higher differentiation of calc-alkaline magmas.Zircon U-Pb dating yields forming ages of 452.2 ±5.3 Ma and 430.2±3.2 Ma for monzogranite and K-feldspar granites,with the εHf (t) values ranging from-8.89 to -6.80 and from-5.33 to-2.19 as well as TDMC Of 1.58～1.69 Ga and 1.33～1.49 Ga,respectively,suggesting they were derived from Meso-Proterozoic crustal materials in the basement.Combined with coeval granitoids occurring widely in both South Tianshan and southern margin of central Tianshan,monzogranites and K-feldspar granites are reprehensive of arc magmatism during early subduction and later mature arc period,suggesting that subduction of South Tianshan ocean crust continued till Silurian.关键词
锆石U-Pb年龄/花岗岩/巴音布鲁克岩体/南天山Key words
zircon U-Pb dating/granite/Bayinbuluke intrusion/South Tiansh引用本文复制引用
魏强,张成立,何贤英,马中平,高晓峰,杨蓉,黄栋,李平..南天山巴音布鲁克花岗岩岩体成因:锆石U-Pb定年、Hf同位素及其地球化学证据[J].地质学报,2017,91(7):1433-1453,21.基金项目
本文为中国地质调查局天山成矿带地质调查评价成果集成项目(编号12120113042200)及西北重大岩浆事件及其成矿作用和构造背景综合研究项目(编号12120114020501)联合资助成果. （编号12120113042200）
