發(fā)布時(shí)間：2018-10-22 14:14

【摘要】：長(zhǎng)江中下游成礦帶銅陵礦集區(qū)內(nèi)的許多礦床皆與中生代巖漿巖的侵入密切相關(guān),選取新橋礦床磯頭巖體為研究對(duì)象,進(jìn)行LA-ICP-MS鋯石U-Pb定年以及巖體地質(zhì)和礦物學(xué)研究。鋯石的高Th/U比值特征及典型巖漿鋯石環(huán)帶顯示其為巖漿成因。磯頭巖體中主體石英閃長(zhǎng)巖16個(gè)測(cè)點(diǎn)的加權(quán)平均年齡為(141.6±1.1)Ma,后期侵入的閃長(zhǎng)玢巖20個(gè)測(cè)點(diǎn)加權(quán)平均年齡為(129.95±0.6)Ma。兩者均形成于早白堊世,礦區(qū)內(nèi)巖漿活動(dòng)至少有兩期,主巖漿作用為141 Ma。磯頭巖體是由幔源巖漿上侵至13~15km中地殼先形成深部巖漿房,發(fā)生結(jié)晶分異和同化混染,隨后在構(gòu)造擾動(dòng)與巖漿脈動(dòng)下,深部巖漿房中的巖漿沿構(gòu)造薄弱面上侵至7~8km,冷凝固結(jié)形成,其結(jié)晶溫度大約為800℃。磯頭巖體約束成礦時(shí)代及成礦作用,新橋礦床經(jīng)由高溫?zé)嵋航淮饔?并經(jīng)后期熱液多次疊加改造成礦。
[Abstract]:Many deposits in Tongling ore concentration area of the middle and lower reaches of the Yangtze River are closely related to the intrusion of Mesozoic magmatic rocks. The LA-ICP-MS zircon U-Pb dating and the geological and mineralogical study of the rock mass are carried out in this paper. The characteristics of high Th/U ratio of zircon and typical magmatic zircon ring show that it is magmatic origin. Weighted mean age of (141.6 鹵1. 1) Ma, intrusive diorite porphyrite from 16 sites in the main quartz diorite is (129.95 鹵0. 6) Ma.. Both of them were formed in the early Cretaceous, and magmatic activity in the ore area was at least two periods. The main magmatism was 141 Ma.. The Jitou rock body was intruded from mantle magma to the middle crust of 13~15km to form deep magma chamber, crystallization differentiation and assimilation, and then under tectonic disturbance and magmatic pulsation, The magma in the deep magma chamber infiltrates up to 7 ~ 8 km along the weak surface of the structure and is formed by condensation and consolidation, and its crystallization temperature is about 800 鈩，

本文編號(hào)：2287387