地质学报2017，Vol.91Issue(12)：2710-2726,17.
胶东昌邑地区古元古代二长花岗岩锆石U-Pb定年、Hf同位素组成及其构造岩浆演化意义
Zircon U-Pb Dating, Hf Isotope Composition and Tectono-Magmatic Evolutionary Significance the Paleoproterozoic Monzogranite in Changyi Area, Eastern Shandong
摘要
Abstract
The Jiaodong area was located in the southern part of the Paleoproterozoic Jiao-Liao-Ji belt.Previously,many studies on the Precambrian geological events in this area have been conducted.However,the Paleoproterozoic intrusive rocks are lack of in-depth study.Based on the detailed field investigation of the Paleoproterozoic monzogranite in Changyi area,we discussed the genesis and formation age of granite and the age of deposit of Fenzishan Group which related to it by analyzing the geochemistry,zircon U-Pb dating and Hf isotopic.The monzogranites studied in this paper have high total alkali content (K2O+Na2O=6.93％ ～8.11％),low Al2O3 (9.89％ ～14.11％),low MgO (0.01％ ～0.63％) and are metaluminous rocks (the saturation index A/CNK is 0.99～1.56).It is obviously depleted in high fieldstrength elements such as Nb,Ta,P and Ti,the degree of fractionation of the light and heavy rare earths is higher.Five samples of zircon LA-MC-ICP-MS and a SHRIMP dating,forming age of 2045±8 Ma～ 2187±9 Ma,indicating that granite was formed in the Paleoproterozoic.The zircon age of the fine-grained monzogranites intrude into the Fenzishan Group is 2080± 9 Ma and according to the previous research results,the deposition time of the Xiaosong Formation in the Fenzishan Group is limited to between 2.1 Ga and 2.2 Ga.According to rock geochemistry and magmatic zircon Hf isotopic compositional characteristics,the monzogranites formed in the upper crust to some extent partially melted,which is supported by the presence of ～2.4 Ga and ～2.7 Ga inherited zircons,and the older crustal materials is the Neo-Archean TTG rocks.关键词
胶东地区/花岗岩/古元古代/锆石U-Pb定年/Hf同位素Key words
Jiaobei area/Grantide/Paleoproterozoic/Zircon U-Pb dating/Hf isotope引用本文复制引用
田瑞聪,李大鹏,侯建华,祝德成,李俊建,田杰鹏,郭瑞朋,黄永波,张鹏鹏..胶东昌邑地区古元古代二长花岗岩锆石U-Pb定年、Hf同位素组成及其构造岩浆演化意义[J].地质学报,2017,91(12):2710-2726,17.基金项目
本文受国家公益性行业性专项(201511029)、国家自然科学基金项目(编号:41672084、41503038、41772076)和中国地质调查局项目(编号:1212011220485、1212010811029、12120114034901)联合资助. （201511029）
