粤西大降坪黄铁矿矿床He-Ar同位素和稀土元素组成及成矿物质来源探讨  

Geochemical Characteristics of He-Ar Isotopes and Rare Earth Elements in the Dajiangping Pyrite Deposit in Western Guangdong,South China

作　　者：李贶[1] 胡凯[1] 蒋少涌[1] 宋世明[1] 

机构地区：[1]南京大学内生金属矿床成矿机制国家重点实验室南京大学地球科学系

出　　处：《南京大学学报（自然科学版）》2006年第6期611-620,共10页Journal of Nanjing University（Natural Science）

基　　金：国家自然科学基金(40221301;40572056);教育部高等学校博士点基金(20030284031)

摘　　要：对大降坪黄铁矿床的Ⅲ、Ⅳ号矿体样品进行了流体包裹体的He-Ar同位素测定，^3He／^4He值在0．13～2．55Ra之间，^40Ar／^36Ar在348-443之间，反映出成矿流体中有地幔流体的侵入．可能是深源地幔的热液沿着大降坪黄铁矿床的逆冲断层进入矿体，对矿体进行了热液改造，分化出Ⅲ号条带状矿体和Ⅳ块状矿体两个不同形态的矿石类型；矿石和围岩的稀土元素的研究结果表明，Ⅲ号矿体和近Ⅲ号矿体围岩及边坡围岩的稀土元素分配曲线基本一致，均表现为铕负异常（8Eu=0．52～0．83），而Ⅳ号块状矿体及近Ⅳ号矿体围岩表现为铕正异常（8Eu=1.03～14．70），可能是受到地幔热液的影响而热液蚀变改造引起的．He-Ar isotopes of fluid inclusions in six measured. The ^3 He/^4 He values ranged from 0. 13 to data indicate that mantle-derived fluids contributed to samples of the Dajiangping pyrite orebodies Ⅲ and IV were 2. 55 Ra and the ^40Ar/^36Ar ratios ranged from 348 to 443. The the ore-forming fluids. This study suggests the hot fluids from the deep mantle intruded into the ore body along the thrust fault, hydrothermed the orebody, and differentiated it into banded orebody Ⅲ and massive orebody Ⅳ Rare earth elements of the ores and wall rocks were also measured in this study. The REE patterns of orebody Ⅲ and the country rocks close to orebody Ⅲ are essentially consistent, showing negative Eu anomailes （δgu=0.52-0. 83）, while orebody Ⅳ and the country rocks close to orebody IV show positive Eu anomailes（δEu= 1.03- 14. 70）. The reason may be owed to the hydrothermal alteration by the intrusion of mantle fluid.

关 键 词：HE-AR同位素 地壳流体 地幔流体 逆冲断层 稀土元素 

分 类 号：P595[天文地球—地球化学]