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现代地质 ›› 2021, Vol. 35 ›› Issue (03): 589-598.DOI: 10.19657/j.geoscience.1000-8527.2021.03.01

• 矿床学 • 上一篇    下一篇

北秦岭西峡龙王庙石墨矿床地球化学特征及成因

阎昆(), 杨延伟(), 王丽伟, 朱荣彬, 卢允申, 赵辉   

  1. 河南省资源环境调查一院,河南 郑州 450000
  • 收稿日期:2020-11-15 修回日期:2021-03-26 出版日期:2021-06-23 发布日期:2021-06-24
  • 通讯作者: 杨延伟
  • 作者简介:杨延伟,男,工程师,1986年出生,地质工程专业,主要从事矿床学、岩石地球化学研究。Email: yyw198677@126.com
    阎 昆,男,工程师,1987年出生,地质工程专业,主要从事固体矿产勘查工作。Email: yankun1234567@sina.com
  • 基金资助:
    河南省财政地质勘查项目(【2019】22号)

Geochemical Characteristics and Genesis of the Longwangmiao Graphite Deposit in Xixia County,North Qinling

YAN Kun(), YANG Yanwei(), WANG Liwei, ZHU Rongbin, LU Yunshen, ZHAO Hui   

  1. The First Institute of Resources and Environmental Investigation of Henan,Zhengzhou,Henan 450000,China
  • Received:2020-11-15 Revised:2021-03-26 Online:2021-06-23 Published:2021-06-24
  • Contact: YANG Yanwei

摘要:

西峡龙王庙石墨矿床位于北秦岭朱阳关—柳泉铺石墨成矿带东部南支,矿体赋存于古元古界秦岭群中深区域变质岩系中,原岩属陆源碎屑岩-碳酸盐岩夹中基性火山岩沉积建造。矿体呈层状、似层状,局部为透镜状产出。矿石构造主要为鳞片状,少量浸染状及块状。矿石主要由含石墨(条带)方解大理岩组成。主量元素整体表现为低Si、低Al、低碱、高CaO、高烧失量的特点,微量元素分析显示大离子亲石元素Rb、U、Th、La、Sm富集,高场强不相容元素Ba、Nb、Ti亏损。Sr/Ba比值为0.55~3.30,平均值2.07。Rb/Sr比值为0.02~1.15,平均值0.28。∑REE含量偏高,REE的分异程度高,轻稀土较重稀土富集,Eu和Ce负异常明显,表明石墨矿变质岩系的原岩可能形成于被动大陆边缘海构造环境。综合分析认为,西峡龙王庙晶质石墨矿床为有机成因的区域变质型晶质石墨矿床,矿床后期叠加热变质及构造改造的特征明显。

关键词: 石墨矿, 地球化学, 矿床成因, 河南西峡

Abstract:

The Longwangmiao graphite deposit in Xixia is located in the southern branch of the eastern Zhuyangguan-Liuquanpu graphite metallogenic belt in the North Qinling Mountains. The orebody occurs in the middle-deep regional metamorphic rock series of the Paleoproterozoic Qinling Group, and the original rock belongs to the terrigenous clastic rock-carbonate sandwiched basic volcanic rock sedimentary formation. The orebody is layered and quasi-layered, and the local occurrence is lenticular. The ore structure is mainly scaly, and a small amount of ore is disseminated or massive. The ore is mainly composed of calcite marble containing graphite (ribbon). The major elements are characterized by low Si, low Al, low alkali, high CaO and high LOI. The analysis of trace elements shows that large ion lithophile elements such as Rb, U, Th, La and Sm are enriched, while high field strength incompatible elements such as Ba, Nb and Ti are deficient. The Sr/Ba ratio ranged from 0.55 to 3.30, with an average of 2.07. The Rb/Sr ratio ranged from 0.02 to 1.15, with an average of 0.28. The content of ∑REE is on the high side, the differentiation degree of REE is high, the LREE is richer than HREE, and the negative anomalies of Eu and Ce are obvious, indicating that the protolith of the graphitic metamorphic rock series may have been formed in the marine tectonic environment of the passive continental margin. Comprehensive analysis shows that the Xixia Longwangmiao crystalline graphite deposit is an organic genetic regional metamorphic crystalline graphite deposit with obvious characteristics of superimposed heating metamorphism and tectonic transformation in the later stage of deposit formation.

Key words: graphite ore, geochemistry, genesis of the deposit, Xixia County,Henan Province

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