山东沂水地区英灵山花岗岩及其捕虏体的地质、岩石地球化学特征和锆石SHRIM PU-Pb定年  

Geological and geochemical characteristics and SHRIMP U-Pb zircon dating of the Yinglingshan granite and its xenoliths in Yishui County, Shandong, China

作　　者：赵子然[1] 宋会侠[1] 沈其韩[1] 宋彪[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037

出　　处：《地质通报》2008年第9期1551-1558,共8页Geological Bulletin of China

基　　金：国家自然科学基金项目《山东沂水古老岩浆杂岩体的时序、成因和演化及围岩年代的限定》(编号40572110)资助。

摘　　要：英灵山花岗岩是新太古代沂水岩浆杂岩的重要组成部分之一,主要分布于沂水县城东南部,总体呈北东向分布。花岗岩的片麻理走向北东,南倾,倾角40～50°,侵入于沂水岩群的二辉斜长角闪岩-黑云变粒岩(黑云斜长片麻岩)-二辉斜长片麻岩变质岩组合中,北部与马山岩体、雪山岩体和大山岩体接触,东南与林家官庄岩体接触。岩石呈中—粗粒,略具片麻状,包体发育,SiO2含量73.36%～74.44%,K2O>Na2O>CaO,稀土元素总量较低,为22.25×10-6～88.82×10-6,弱—中等的正Eu异常,轻、重稀土元素分馏较强,La/Yb=11～47,富集K、Rb、Ba等大离子亲石元素和Er、Hf等高场强元素,亏损Sr、Ta、Nb、P等元素,成分上属钾质花岗岩。2个样品YS06-30和YS06-48的锆石SHRIMPU-Pb定年结果分别是2530Ma±7Ma和2531Ma±8Ma,属于新太古代。The Yinglingshan granite, which is mainly distributed in the southeast of the seat of Yishui County, is one of the most important component parts of the Neoarchean Yishui magmatic complex. The gneissosity of granite strikes NE and dip S at 40-50°. The granite is intruded into the Yishui Group-complex composed of a metamorphic rock association of two-pyroxene amphibolite - biotite-plagioclase fine-grained gneiss - two-pyroxene-plagioclase gneiss, and its northern margin is in contact with the Mashan, Xueshan and Dashan granite bodies, while its southeast part is in contact with the Linjiaguanzhuang rock body. The rock is medium to coarse-grained and slightly gneissoid and contains abundant xenoliths. The contents of SiO2 range from 73.36 to 74.44 wt% with K2O〉Na2O〉CaO. The total content of rare earth elements （REE） are low, varying from 22.25 to 88.82 ppm, and there are obvious fractionations between HREE and LREE. The La/Yb ratios vary from 11 to 47. The rock is enriched in large-ion lithophile elements such as K, Rb and Ba and high-field strength elements such as Er and Hf and depleted in Sr, Ta, Nb and P. Positive Eu anomalies are weak to moderate. So the rock is compositionally potassic granite. The zircon SHRIMP U-Pb dating of samples YS06-30 and YS06-48 yield 2530±7 and 2531±8 Ma respectively, indicating a Neoarchean age.

关 键 词：山东 沂水岩浆杂岩 英灵山岩体 岩石地球化学 锆石SHRIMP U-PB定年 

分 类 号：P588.121[天文地球—岩石学] P595[天文地球—地质学]