地质通报2017，Vol.36Issue(2)：402-417,16.
安徽繁昌浮山钾长花岗岩成因及其构造意义——来自锆石U-Pb年龄、岩石地球化学和Hf同位素的证据
Petrogenesis and tectonic implications of the Fushan moyite in the Fanchang area,Anhui Province-Evidence from zircon U-Pb age,geochemistry and Hf isotopes
摘要
Abstract
The Fanchang area is one of the important components of the Middle- Lower Yangtze Valley metallogenic belt. The Fushan moyite is one of the most representative and important granitic intrusions. In this paper, LA-ICP-MS zircon U-Pb dating, petrographic observations and geochemical and Hf isotopic analysis were carried out for the Fushan moyite in the Fanchang area, with the emphasis placed on the analysis of petrogenesis and tectonic implications of the Fushan moyite. The Fushan moyite has a clear A-type geochemical signature, e.g., it is of metaluminous to weakly peraluminous nature (A/CNK=0.91~1.11) and has high SiO2 (averagely 71.52%), total alkalis (Na2O+K2O=8.85%~9.60%), K?(K2O/Na2O=1.06~1.57), Fe?(TFeO/MgO=2.49~10.2), rare earth elements (ΣREE=278×10-6~376×10-6), Ga/Al ratio (2.90~3.31) and HFSE (Zr+Nb+Ce+Y=421.8×10-6~655.0×10-6). LA-ICP-MS zircon U-Pb dating yielded a concordant weighted mean 206Pb/238Pb age of 124.9±2.0Ma, which is similar to ages of other A-type granites in the Middle-Lower Yangtze Valley metallogenic belt, indicating that all A-type granites were formed in the Early Cretaceous. Zircons from this pluton yielded εHf(t) values between -5.8 and -10.0, which, together with U-Pb age,(87Sr/86Sr)I,δ18O and εNd(t) values of the Fushan moyite, suggest the importance of juvenile material in the magma source, and the juvenile ma-terial was composed of the basaltic andesitic magma from enriched mantle lithosphere and minor crystalline metamorphic basement. These data, together with other accurate dating data of intermediate-acid plutons and volcanic rocks in the Middle-Lower Yangtze Valley metallogenic belt, support the peak time of crustal extension at ~125Ma in this area.关键词
钾长花岗岩/LA-ICP-MS锆石U-Pb年龄/Lu-Hf同位素/岩石成因/长江中下游地区Key words
moyite/LA-ICP-MS zircon U-Pb ages/Lu-Hf isotopes/petrogenesis/Middle-Lower Yangtze Valley分类
天文与地球科学引用本文复制引用
庞振山,高浮萍,朱晓强,东前,林鲁军..安徽繁昌浮山钾长花岗岩成因及其构造意义——来自锆石U-Pb年龄、岩石地球化学和Hf同位素的证据[J].地质通报,2017,36(2):402-417,16.基金项目
中国地质调查局项目《皖赣沿江地区壳幔相互作用与多成因矽卡岩矿床成矿机制研究》(编号:121201113069900)、《安徽铜陵矿集区找矿预测》(编号:12120115034401) （编号:121201113069900）
