青海省它温查汉西铁多金属矿床地质特征及成因分析  

Geological characteristics and genetic analysis of the Tawenchahanxi Fe-polymetallic deposit, Qinhai Province

作　　者：杨涛[1] 张乐 郑振华 赵寒森[1] 宋忠宝[1] 马永胜 王瑾 陈向阳[1] 曹德智 YANG Tao;ZHANG Le;ZHENG Zhen-hua;ZHAO Han-sen;SONG Zhong-bao;MA Yong-sheng;WANG Jin;CHEN Xiang-yang;CAO De-zhi(Xi＇ an Center of China Geological Survey, Xi＇ an 710054, China;Geophysical and Geochemical Exploration Corporation, Northwest Bureau of Geological Exploration for Nonferrous Metals, Xi＇ an 710068, China;Geological Survey Bureau of Qinghai Province, Xining 810012, China;The Fourth Geological and Mineral Exploration Academy of Qinghai Province, Xining 810012, China)

机构地区：[1]中国地质调查局西安地质调查中心,陕西西安710054 [2]西北有色地质勘查局物化探总队,陕西西安710068 [3]青海省地质调查局,青海西宁810012 [4]青海省第四地质矿产勘查院,青海西宁810012

出　　处：《岩石矿物学杂志》2018年第3期467-484,共18页Acta Petrologica et Mineralogica

基　　金：中国地质调查局地质调查项目(1212011121089)~~

摘　　要：它温查汉西铁多金属矿床是青海省祁漫塔格地区新发现的又一中型矿床,矿体与成矿岩体均隐伏于第四系风积砂覆盖层下。本文利用LA-ICP-MS锆石U-Pb定年方法,获得与成矿密切相关的花岗闪长斑岩的成岩年龄为236.0±2.3 Ma,与成矿时代基本一致,为晚古生代-早中生代构造-岩浆旋回的碰撞-后碰撞转化阶段岩浆活动的产物,形成于加厚的地壳背景。花岗闪长斑岩为弱过铝质高钾钙碱性系列,微量元素配分具有LREE和HFSE富集、HREE和LILE亏损以及中等负Eu异常的特征。其成因类型属于Ⅰ型,具有壳幔混源的性质,与区域上大规模幔源岩浆底侵及壳-幔岩浆混合作用有关。它温查汉西铁多金属矿床主要产于花岗闪长斑岩与祁漫塔格群碳酸盐岩的接触带附近,属于典型的矽卡岩矿床。矿体类型分为交代型铁氧化物矿体和细脉型多金属硫化物矿体两种,矿化大致分为矽卡岩阶段、退化蚀变阶段及硫化物-石英阶段。The Tawenchahanxi Fe-polymetallic deposit is a medium-sized deposit newly discovered in Qimantag area of Qinghai Province. In this area the orebody and metallogenic rock body are both covered by Quaternary eolian sandstone. By using LA-ICP-MS zircon U-Pb isotope dating, the authors obtained the petrogenetic age of the granite diorite porphyry(236. 0 ± 2. 3 Ma.） which is the main ore-forming rock mass in the ore deposit. The result is close to the age of Tawenchahanxi deposit. It might have been formed at the collision-post collision conversion stage of Late Paleozoic to Early Mesozoic tectono-magmatic cycle associated with the crustal thickening setting. On the basis of chronological, petrologic and geochemical studies, the authors have revealed that the granodiorite porphyry is a peraluminous, high K calc-alkaline series granite, which is enriched in LREE and HFSE and depleted in HREE and LILE, with medium negative Eu anomalies. The granodiorite porphyry belongs to the I-type and crust-mantle magma mixing source, related to regional large-scale mantle magma underplating and crust-mantle magma mixing.The Tawenchahanxi Fe-polymetallic deposit is a typical skarn deposit, which is mainly distributed in the contact zone between granodiorite porphyry and Qimantag Group carbonatite. There are two type of orebodies(metasomatic iron-oxide orebody and veinlet sulfide polymetallic orebody） in the ore deposit, and the evolution of the ore-forming fluid can be divided into skarn stage, retrograde alteration stage and sulfide-quartz stage.

关 键 词：中型 花岗闪长斑岩 Ⅰ型 壳-幔岩浆混合 矽卡岩 它温查汉西 青海省 

分 类 号：P618.31[天文地球—矿床学]