青海野马泉铁锌矿床二长花岗岩锆石U-Pb和金云母Ar-Ar测年及地质意义

发布时间：2018-06-26 17:14

本文选题：锆石U-Pb年龄 + 金云母Ar-Ar年龄　；参考：《大地构造与成矿学》2017年06期

【摘要】：青海野马泉铁锌矿床地处祁漫塔格山与柴达木盆地之间的盆山结合部位,是矽卡岩型铁锌多金属矿床。矿体均呈隐伏?半隐伏状产出、具多期次强烈岩浆活动叠加等特征。长期以来,有关野马泉铁锌多金属矿床的成矿岩体和成矿时代众说纷纭,制约了对该矿床成因机制的认识及进一步的矿产勘查工作。本文基于详细的野外实地调查和矿床地质特征解剖,开展了成岩成矿年龄精测,探讨了成矿构造环境。铁锌矿体产于二长花岗岩与围岩地层的外接触带,发育石榴子石、透辉石、金云母、绿帘石等矽卡岩化作用。利用LA-ICP-MS锆石U-Pb法,获得成矿二长花岗岩的年龄为229.5±2.2 Ma(n=22,MSWD=1.3);采用Ar-Ar分步升温法获得与磁铁矿共生的金云母坪年龄为222.0±1.3 Ma(MSWD=0.41)、等时线年龄为222.4±2.5 Ma(MSWD=1.4),证实野马泉铁锌多金属矿床形成于晚三叠世,成矿岩体属过铝质、高钾钙碱性系列,为I-A过渡型花岗岩,具有高SiO_2,高K_2O/Na_2O,低P_2O_5,低Sr高Yb的特点。结合区域其他多金属矿床最新成岩成矿年代学数据,认为野马泉矿床形成于东昆仑地区海西?印支造山旋回晚期、由碰撞向后碰撞转换的地质构造环境。
[Abstract]:The Qinghai wild Ma Quan iron and zinc deposit is located in the joint of the basin and mountain of the qimamu mountain and the Qaidam Basin. It is a skarn type iron zinc polymetallic deposit. The ore bodies are concealed, semi concealed and superimposed by multiple periods of intense magma activity. For a long time, the ore-forming rock mass and metallogenic epoch of the yama spring iron and zinc polymetallic deposit have been used for a long time. On the basis of detailed field investigation and geological feature anatomy, the age of diagenesis and mineralization is measured and the metallogenic tectonic environment is discussed. The iron and zinc ore bodies are produced in the outer contact zone between the two long granite and the surrounding rock formation, and the garnet is developed. Diopside, gold mica, epidote and other skarn effects. Using LA-ICP-MS zircon U-Pb method, the age of two granites was 229.5 + 2.2 Ma (n=22, MSWD=1.3). The age of gold mica flat with magnetite was 222 + 1.3 Ma (MSWD=0.41), and the isochronous age was 222.4 + 2.5 Ma (MSWD=1.4). The Ma Quan iron zinc polymetallic deposit was formed in the late three fold. The ore-forming rock belongs to the Peraluminous, high potassium calc alkaline series and I-A transitional granite. It has the characteristics of high SiO_2, high K_2O/Na_2O, low P_2O_5 and low Sr high Yb. The tectonic setting of the late Indosinian orogenic cycle, which was converted from collision to collision.
【作者单位】：中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室;青海省第三地质矿产勘查院;
【基金】：青海省地质勘查基金(201304) 国土资源部公益性行业科研专项经费(201411025) 中国地质调查局地质调查项目(1212011085528),中国地质调查局高层次地质人才培养计划(201309) 青年地质英才计划(201112)联合资助
【分类号】：P588.121;P618.2

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