张伟, 邹林, 唐文春, 黄健, 段威, 杨贵兵, 范映武, 李小松, 黄建国. 川西热达门伟晶岩型稀有金属矿床锂辉石C-H-O同位素组成及意义[J]. 矿产综合利用, 2023, 44(1): 45-54, 69. DOI: 10.3969/j.issn.1000-6532.2023.01.006
    引用本文: 张伟, 邹林, 唐文春, 黄健, 段威, 杨贵兵, 范映武, 李小松, 黄建国. 川西热达门伟晶岩型稀有金属矿床锂辉石C-H-O同位素组成及意义[J]. 矿产综合利用, 2023, 44(1): 45-54, 69. DOI: 10.3969/j.issn.1000-6532.2023.01.006
    Zhang Wei, Zou Lin, Tang Wenchun, Huang Jian, Duan Wei, Yang Guibing, Fan Yingwu, Li Xiaosong, Huang Jianguo. The C-H-O Isotopic Composition and Significance of Spodumene for Redamen Pegmatite Type Rare Metal Deposit in Western Sichuan[J]. Multipurpose Utilization of Mineral Resources, 2023, 44(1): 45-54, 69. DOI: 10.3969/j.issn.1000-6532.2023.01.006
    Citation: Zhang Wei, Zou Lin, Tang Wenchun, Huang Jian, Duan Wei, Yang Guibing, Fan Yingwu, Li Xiaosong, Huang Jianguo. The C-H-O Isotopic Composition and Significance of Spodumene for Redamen Pegmatite Type Rare Metal Deposit in Western Sichuan[J]. Multipurpose Utilization of Mineral Resources, 2023, 44(1): 45-54, 69. DOI: 10.3969/j.issn.1000-6532.2023.01.006

    川西热达门伟晶岩型稀有金属矿床锂辉石C-H-O同位素组成及意义

    The C-H-O Isotopic Composition and Significance of Spodumene for Redamen Pegmatite Type Rare Metal Deposit in Western Sichuan

    • 摘要: 热达门稀有金属矿床位于川西可尔因伟晶岩型矿田的南西部,文章在详细的矿床地质特征研究基础上,系统采集同一矿脉同一矿体不同标高(3540~3830 m)的矿石,分析测试了锂辉石单矿物中的C-H-O同位素组成以及不同矿物中的包裹体特征。矿物中包裹体主要以富液相包裹体为主,锂辉石中包裹体盐度集中于8%~20%,均一温度180~330℃,属于中-低盐度、中-高温成矿流体;石英中包裹体盐度集中于0%~8%,均一温度150~240℃,属于低盐度、低温流体。C-H-O同位素测试结果显示热达门稀有金属矿床中的锂辉石δD值为-97.5‰~-104.7‰(平均-102.8‰),相对于可尔因地区其他锂矿床,δD值明显偏小,δ18OH2O值为-0.34‰~2.88‰(平均1.032‰),表明成矿流体可能有大气降水的混入,并受到了围岩黑云母而长花岗岩体的影响。矿床中锂辉石的δ13CV-PDB值为-10‰~-16.6‰,平均-12.7‰,反映主成矿期碳的来源具有岩浆系统和大气降水系统的混合性质,与岩浆-地幔源(花岗岩、地幔多相体系)的低温蚀变有关,并可能混入部分由沉积有机物质经脱羧基作用(decarboxylation)生成CO2。通过对矿物C-H-O同位素及流体包裹体进行研究,进一步明确了成矿流体来源及演化过程。

       

      Abstract: The Redamen rare metal deposit is located in the south western part of Keeryin pegmetite typed ore field in western Sichuan. It is a special deposit in the aspects of surrounding rock, element mineralization zoning and distance. The ore with different elevation (3540~3830 m) of the same vein and the same orebody is systematically collected, spodumene single mineral is selected to analyze the C-H-O isotope composition and features of inclusions in different minerals.The inclusions in minerals are mainly liquid-rich inclusions. The salinity of the inclusions in spodumene is 8%~20%, and the homogenization temperature is 180~330℃. The inclusions belong to the ore-forming fluid with medium-low salinity and medium-high temperature. The inclusions in quartz have salinity of 0%~8%, homogenization temperature of 150~240℃, and belong to low salinity and low temperature fluid. The results of C-H-O isotope test show that the δD/‰ of spotamene in the Redamen rare metal deposit ranges from -97.5 to -104.7 (average of -102.8). Compared with the Lijiagou deposit in the southeast of the ore field, the δD/‰ of spodumene is obviously smaller, with the δ18OH2O/‰ ranging from -0.34 to 2.88 (average of 1.032). However, it is basically consistent with the main metallogenic period of spodumene in Lijiagou deposit, indicating that the ore-forming fluid of late mineralization (that is, the main metallogenic period of spodumene) is mixed with meteoric water. The δ13CV-PDB/‰ of spodumene in the Redamen rare metal deposit ranges from -10 to -16.6, with an average of -12.7, indicating that the carbon source in the main mineralization period (spodumene formation period) has a mixed nature of magmatic system and meteoric precipitation system, which is related to the low temperature alteration of magmatic mantle source (granite, mantle multi-phase system) and may be mixed with CO2 generated by the decarboxylation of deposited organic materials. Through the study of mineral C-H-O isotopes and fluid inclusions, the source and evolution process of ore-forming fluids were further clarified.

       

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