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现代地质 ›› 2012, Vol. 26 ›› Issue (3): 478-488.

• 矿床学与构造学 • 上一篇    下一篇

豫西雷门沟斑岩钼矿床钾长石化蚀变特征及其成矿意义

 陈小丹1, 叶会寿2, 汪欢1   

  1. 1 中国地质大学  地球科学与资源学院,北京100083;2 中国地质科学院 矿产资源研究所,北京100037
  • 收稿日期:2011-11-25 修回日期:2012-03-28 出版日期:2012-06-07 发布日期:2012-06-14
  • 通讯作者: 叶会寿,男,研究员,1964年出生,矿物学、岩石学、矿床学专业,主要从事金属矿产研究及找矿勘查工作。Email: yehuishou@163.com。
  • 作者简介:陈小丹,女,硕士研究生,1988年出生,矿物学、岩石学、矿床学专业,主要从事矿床地球化学研究。Email:sunshinecxd@126.com。
  • 基金资助:

    国土资源部全国危机矿山接替资源找矿项目(20089949,200841019)

Alteration Characteristics of Kfeldspar in Leimengou Porphyry Mo Deposit in Western Henan Province and Its Insight into Metallogenetic Process

 CHEN  Xiao-Dan-1, XIE  Hui-Shou-2, HONG  Huan-1   

  1. 1 School of Earth Sciences and Resources, China University of Geosciences, Beijing100083,China; 2 Institute of Mineral Resources,Chinese Academy of Geological Sciences, Beijing100037,China)
  • Received:2011-11-25 Revised:2012-03-28 Online:2012-06-07 Published:2012-06-14

摘要:

豫西雷门沟钼矿床属于东秦岭钼矿带典型的斑岩型矿床之一,矿床广泛发育钾长石化,呈面型和线型2种形式产出。据野外观察,面型钾长石化以成矿前钾长石化蚀变围岩为特征,包括钾长石化花岗斑岩和钾长石化片麻岩,蚀变岩石主要由钾长石构成,少量石英和斜长石残留,蚀变强烈时石英、斜长石等消失,全岩钾长石化,为成矿前围岩蚀变;线型钾长石化包括钾长石细脉、钾长石-萤石辉钼矿脉和石英辉钼矿脉边部的钾长石化晕,钾长石呈脉状充填或者交代脉边部的石英,为成矿阶段蚀变。电子探针成分分析表明,蚀变形成的钾长石K2O含量较高,Na2O、CaO含量较低。X衍射结构显示,蚀变形成的钾长石为微斜长石,蚀变温度为310~418 ℃,表明由碱性热液交代形成。Pb同位素组成显示钾长石中K质主要来源于地幔。根据成矿热液具有富碱质的地幔来源特征,结合Mo元素地球化学特征,认为退化碱质交代作用有助于雷门沟斑岩钼矿床的形成。

关键词: 钾长石化, X衍射, Pb同位素, 雷门沟斑岩钼矿床, 豫西

Abstract:

 Leimengou Mo deposit in Western Henan Province is a typic porphyry Mo deposit in East Qinling Molybdenum belt. The deposit pervasively develops K-feldspar alteration,including vein type and whole rock alteration. The whole rock alteration charactered as the porphyry and the gneiss being potassic altered absolutely. Vein type alteration is represented by the K-feldspar slevage, K-feldspar fluorite vein amd K-feldspar halo beside the margin of quartz molybdenum veinnet. This paper analyzed the alteration features of K-feldspar, composition of altered minerals, X-ray powder diffraction and Pb isotope composition of types of altered K-feldspar. The compositions of feldspar show that K2O is the main compontent; X-ray powder diffraction data suggest that K-feldspar are andesine microcline with alteration temperatures of 310-418 ℃.Pb isotope composition show that K in K-feldspar originates from mantle. According to the  mantle derived characteristics of the ore forming fluid, combining with the geochemistry of Mo, we conducted that the K-feldspar alteration has a good interpretation on the metallogenic process.

Key words: K-feldspar alteration, X-ray diffraction, Pb isotope, Leimengou porphyry Mo deposit;Western Henan Province