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

• Ore Deposits • Previous Articles     Next Articles

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

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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