吉黑东部矽卡岩型钨矿床白钨矿原位微量元素特征及其指示意义  

In-Situ Trace Elements Characteristics of the Scheelite and Metallogenic Significance on Skarn Tungsten Deposits in Eastern Jilin and Heilongjiang Province,NE China

作　　者：任云生 李京谋 郝宇杰 徐文坦 Ren Yunsheng;Li Jingmou;Hao Yujie;Xu Wentan(School of Earth Science,Institute of Disaster Prevention,Langfang 065201,Hebei,China;School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;Key Laboratory of Mineral Resources Evaluation in Northeast Asia,Ministry of Natural Resources of China,Changchun 130061,China)

机构地区：[1]防灾科技学院地球科学学院,河北廊坊065201 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]自然资源部东北亚矿产资源评价重点实验室,长春130061

出　　处：《吉林大学学报（地球科学版）》2023年第6期1706-1721,共16页Journal of Jilin University：Earth Science Edition

基　　金：国家重点研发计划项目(2017YFC0601304)。

摘　　要：矽卡岩型白钨矿矿床是吉黑东部重要的钨矿类型,以黑龙江省逊克县翠宏山钨多金属矿床和吉林省汪清县白石砬子钨矿床为典型代表。为确定区内矽卡岩型钨矿床中的成矿流体特征及成矿机制,选取2个代表性矿床中的白钨矿单矿物进行了原位微区微量元素分析。结果表明:翠宏山钨多金属矿床中的白钨矿具有左倾型的稀土元素配分模式和弱的正Eu异常,形成于富Na、Nb的流体环境中,白钨矿中REE^(3+)通过2Ca^(2+)=REE^(3+)+Na^(+)和Ca^(2+)+W^(6+)=REE^(3+)+Nb^(5+)机制替换Ca^(2+);白石砬子钨矿床中的白钨矿具有右倾型的稀土元素配分模式和正Eu异常,形成于贫Na、Nb的流体环境中,白钨矿中REE^(3+)通过3Ca^(2+)=2REE^(3+)+Ca(是Ca的空位)机制替换Ca^(2+)。两矿床中白钨矿Eu_(N)与Eu_(N)^(*)之间明显的相关关系及较高的Mo质量分数表明,吉黑东部矽卡岩型钨矿床中白钨矿的成矿流体均为氧化性流体。在协变关系图解中,翠宏山和白石砬子矿床中的白钨矿与各自成矿岩体在Y和Ho质量分数之间的良好相关性、Y/Ho和La/Ho值协变关系中的明显差异性,揭示2个矿床的初始成矿流体来源于岩浆,在流体演化过程中发生了水岩反应和流体混合作用;2个矿床中白钨矿Eu异常均高于其各自成矿岩体的Eu异常,进一步指示流体演化过程中发生了水岩反应。岩浆热液上升运移过程中的流体混合作用和水岩反应是吉黑东部矽卡岩型钨矿床白钨矿沉淀富集的主要机制。The skarn-type scheelite deposit is an important type of tungsten deposits in eastern Jilin and Heilongjiang of Northeast(NE)China.The large-scale Cuihongshan Wo-polymetallic deposit in Xunke area of Heilongjiang Province and medium-scale Baishilazhi scheelite deposit in Wangqing area of Jilin Province are two representative skarn deposits.To determine their ore-forming fluid characteristics and metallogenic mechanism,scheelite single minerals were selected from these two representative deposits for in-situ LA-ICP-MS trace elements analysis.The results show that the scheelite in Cuihongshan deposit was formed in a Na-and Nb-rich ore-forming fluid system with left-dipped rare earth element(REE)distribution patterns and weak positive Eu anomalies.The substitution of REE^(3+)for Ca^(2+)in scheelite from Cuihongshan deposit can be accounted for the substitution mechanism:2Ca^(2+)=REE^(3+)+Na^(+)and Ca^(2+)+W^(6+)=REE^(3+)+Nb^(5+).The scheelite in Baishilazi deposit was formed in a Na-and Nb-poor ore-forming fluid system with right-dipped REE distribution patterns and positive Eu anomalies.The substitution mechanism of REE^(3+)for Ca^(2+)in scheelite of Baishilazi deposit is 3Ca^(2+)=2REE^(3+)+□Ca(where□is a site vacancy).The obvious correlation between Eu_(N)and Eu_(N)^(*)and the high Mo content in scheelite samples indicates that the ore-forming fluids in two skarn-type tungsten(-polymetallic)deposits in eastern Jilin and Heilongjiang are oxidizing fluids.The Eu anomalies of scheelite in these two deposits are higher than those of their ore-forming intrusions,indicating that water-rock reaction occurred during the fluid evolution.The obvious correlation of Y and Ho contents between the scheelite in different deposits and their ore-forming intrusions,as well as the differences between Y/Ho and La/Ho,reveal that their initial ore-forming fluids are derived from magmatism,and water-rock reaction and fluid mixing occurred during the fluid evolution.Due to data from this studies and previous references,it can be conc

关 键 词：成矿流体 成矿机制 原位微量元素 白钨矿 矽卡岩型钨矿床 翠宏山钨多金属矿床 白石砬子钨矿床 吉黑东部 

分 类 号：P611.1[天文地球—矿床学] P575.3[天文地球—地质学]