摘要
祁漫塔格地区发现了一大批与中酸性岩浆侵入活动有关的金属矿床,已成为青海省乃至中国西部最重要和最有找矿潜力的铁、铜、铅锌多金属成矿带。通过鸭子沟二长花岗岩岩相学、岩石地球化学研究,探讨了其岩石成因、构造背景及与成矿的关系。结果表明:鸭子沟二长花岗岩具有高硅、钾,富碱,贫铝、钙、镁,低铁的特点,属弱过铝质高钾钙碱性系列岩石;∑REE含量平均为181.24×10^-6,δEu为0.07~0.11,平均为0.09,Eu强烈亏损;稀土元素球粒陨石标准化配分模式图呈稍右倾的“V”字形曲线,轻重稀土分馏作用不明显;岩体明显富集大离子亲石元素Rb和K、活泼的不相容元素U和Th以及Pb,相对亏损高场强元素Nb、Ta、P和Ti以及大离子亲石元素Ba和Sr。鸭子沟二长花岗岩属于A 2型花岗岩,形成于碰撞造山背景下的后碰撞阶段,区内产出有斑岩型铜钼矿点和矽卡岩型铅锌矿点,应重视晚三叠世二长花岗岩体中的找矿工作。
The metal deposits,related to acid-intermediate magmatic intrusive activities,have been discovered in Qimantag area,and the area has become the most important and favorable prospecting Fe-Cu-Pb-Zn multimetallic metallogenic belt.Through the petrography and rock geochemistry study of adamellite in Yazigou area,the authors discussed its petrogenesis,tectonic setting and relation with mineralization.The results show that Yazigou adamellite has the typical features of high silicic,potassium and alkali contents and low aluminium,calcium,magnesium and iron contents,and the rocks belong to weakly peraluminous and high-kalium calc-alkaline rock series.The average value of ∑REE is 181.24×10^-6 and the values ofδEu are 0.07~0.11,with the average value of 0.09,indicating a remarkable Eu depletion.The rare earth patterns of rocks/chondrite show slightly right-dipping V-type curves,and light and heavy rare earth fractionation is not obvious.The rocks are significantly enriched in large ion lithophile elements of Rb,K,and active incompatible elements of U,Th,Pb,while high field strength elements of Nb,Ta,P,Ti,and large ion lithophile elements of Ba and Sr are relatively depleted.The adamellite of Yazigou region belongs to A 2-type granite,which was formed in post-collision stage of collisional orogenic setting.This area has many porphyry-type copper molybdenum and skarn-type lead-zinc ore occurrences,so the prospecting work should be emphasized in adamellite of Late Triassic epoch.
作者
王盘喜
王振宁
WANG Panxi;WANG Zhenning(Zhengzhou Institute of Multipurpose Utilization of Mineral Resources,Chinese Academy of Geological Sciences,Zhengzhou 450006,China;National Research Center of Multipurpose Utilization of Non-metallic Mineral Resources,Zhengzhou 450006,China;Northwestern China Center for Geosience Innovation,Xi’an 710054,China)
出处
《中国地质调查》
2020年第1期38-46,共9页
Geological Survey of China
基金
中国地质调查局“青海祁漫塔格金属矿集区综合地质调查(编号:DD20160073)”和“长江中游黄石—萍乡—德兴矿山集中区综合地质调查(编号:DD20190269)”项目联合资助
关键词
二长花岗岩
地球化学特征
地质意义
祁漫塔格
adamellite
geochemical characteristics
geological implication
Qimantag
