投稿时间：2011-06-29
修订日期：2012-02-27
中文摘要:西藏甲玛铜多金属矿床是近年来在冈底斯成矿带内中东段找到的超大型斑岩矿床之一。根据甲玛矿区165个钻孔角岩中裂隙的统计结果,从平面上和垂向上研究甲玛斑岩矿床裂隙的分布特征及其与上覆围岩金属矿化强度之间的关系,认为整个矿区破裂裂隙疏密分布趋势明显,裂隙高密度区位于ZK1616—ZK3216一带,平均裂隙率达40条/m以上,最高可达82条/m;并以此为中心向四周发散,裂隙率逐渐降低。而上覆围岩(角岩)中的铜钼矿化强度同裂隙发育程度呈正相关,平面上裂隙高密度区对应的Cu品位值为0.2%~0.47%,对应的Mo品位值为0.03%~0.10%;垂向上裂隙发育程度与铜钼矿化同样具有很好的对应关系,即裂隙越发育,对应的金属矿化越好,且在角岩中具"上铜下钼"的矿化分带现象。此外,根据对矿区裂隙成因的初步讨论,提出了甲玛斑岩矿床裂隙系统的演化模式,并结合16号勘探线上裂隙产状变化的研究成果,进一步确定了甲玛深部隐伏斑岩体的位置。
Abstract:Recently the Jiama copper polymetallic deposit has become one of the superlarge porphyry deposits with significant exploration breakthrough in the mid-eastern part of Gangdise metallogenic belt within Tibet. According to statistic data of fissures in hornfels obtained from 165 drill holes, the authors studied the distribution features of fissures in the Jiama porphyry deposit in relation to metal mineralization of the covering wall rocks in both horizontal direction and vertical direction. This paper points out that the fissure system has distinct distribution trend, and most fissures-crowded places are located along the zone from No.1616 to No.3216 drill holes, with the average fissure rate reaching more than 40 pieces per meter, even 82 pieces per meter at the tiptop which serves as the center of dispersion, and the fissures rate decreases outwards. The copper-molybdenum mineralization of the wall rocks is in positive correlation with the fissure rate. In horizontal direction, the fissures-crowded area has copper grade from 0.2% to 0.47% and molybdenum grade from 0.03% to 0.10%. In vertical direction, the similar phenomena also exist. There is a mineralization zone characterized by copper in the upper part and molybdenum in the lower part in hornfels. This paper also discusses briefly the reason of the fissure formation and puts forward the evolution model of the fissures system in the Jiama porphyry deposit so as to delineate the porphyry body in depth, on the basis of the research result of the attitude variation of fissures along No.16 exploration line.
keywords:geology Jiama porphyry deposit fissure system copper and molybdenum mineralization hornfels Tibet
文章编号：
中图分类号：P618.41; P618.65
文献标志码：
基金项目:本文得到国家973项目(2011CB403103)、中央公益性行业科研专项(200911007-02)、青藏专项(1212010818089)和技术开发项目(E0804)的联合资助
引用文本：
林彬,唐菊兴,张志,郑文宝,冷秋锋,钟婉婷,应立娟.2012.西藏甲玛斑岩矿床裂隙系统的初步研究及意义[J].矿床地质,31(3):579~589LIN Bin,TANG JuXing,ZHANG Zhi,ZHENG WenBao,LENG QiuFeng,ZHONG WanTing,YING LiJuan.2012.Preliminary study of fissure system in Jiama porphyry deposit of Tibet and its significance[J].Mineral Deposits31(3):579~589
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