投稿时间：2016-04-22
修订日期：2017-06-26
网络发布日期：2017-11-06
中文摘要:西南铜钼矿段位于中国著名的福建上杭县紫金山矿田内，是该矿田最新发现的另一个典型的斑岩型矿床。该矿床形成于白垩纪，矿化（浸染状和细脉浸染状）与成矿同期花岗闪长斑岩密切相关。围岩蚀变由深到浅分别为青磐岩化带、绢英岩化带、高级泥化-泥化蚀变带和氧化带。蚀变矿化期次可划分为：（早期）绢英岩化期、斑岩矿化期、浅成低温热液叠加期、成矿后期脉和表生期。其中，斑岩矿化期又可分为钾硅酸盐化阶段、青磐岩化阶段和（晚期）绢英岩化阶段；浅成低温热液叠加期主要为泥化-高级泥化蚀变。对比研究发现，西南矿段具有与典型斑岩矿床相似的矿化蚀变特征，但缺失钾化带且矿化规模小，成矿斑岩以岩枝状（非岩株状）水平侵位，产生非对称蚀变分带，据此推测西南矿段深部可能存在真正的成矿斑岩岩株和大储量及高品位的矿化中心。通过短波红外光谱（SWIR）研究发现，从矿化中心到外围，伊利石结晶度值（IC）和伊利石2200 nm吸收峰位值（Pos2200）均有明显的从高值到低值的变化趋势。此外，研究发现高IC值（>2.1）和高Pos2200值（>2203 nm）可作为紫金山地区勘查该类矿床的找矿标志。本研究可以为紫金山地区斑岩矿床的成矿规律认识和找矿勘查提供科学依据。
Abstract:The Xinan Cu-Mo deposit is a newly-discovered Cretaceous porphyry deposit located in the Zijinshan orefield, Shanghang County, Fujian Province. The Cu-Mo mineralization mainly occur in dissemination and veinlet-dissemination forms, associated with the granodiorite porphyry. From bottom upward, the Xinan deposit generally exhibits propylitic, phyllic, (advanced-) argillic alteration and supergene oxidation. Five stages of hypogene alteration-mineralization were recognized in the Xinan deposit:the early phyllic alteration; porphyry mineralization alteration, consisting of potassic, propylitic and (late) phyllic alteration; overlapping epithermal alteration, which includes (advanced-) argillic alteration; late veined alteration; and supergene alteration. A comparison indicates that the Xinan deposit shows similar mineralization and alteration features to typical porphyry deposits, but it lacks potassic alteration zone and the mineralization is at small scale in the deposit. The ore-bearing granodiorite porphyry intruded flatly as an apophysis (not a stock) into the deposit. It is thus inferred that the real ore-bearing porphyry stock and potential porphyry mineralization (with large reserves and high grades) probably occur in the depth of the Xinan ore district. SWIR research on the Xinan deposit reveals that the illite crystallinity (IC) and the position of illite 2200 nm absorption peak (Pos2200) both show strong gradients from high values to low values from the mineralized center to the distal barren area. Meanwhile, the SWIR anomalies (IC values >2.1 and Pos2200 value>2203 nm) can be used as the indicators of the mineralized porphyry deposits in the Zijinshan orefield. The results obtained by the authors provide scientific basis for further understanding of the metallogenic patterns of porphyry deposits and future exploration of mineral resources in the Zijinshan orefield.
keywords:geology alteration zone alteration and mineralization sequence short wavelength infra-red (SWIR) illite crystallinity (IC) Xinan Cu-Mo deposit Zijinshan orefield
文章编号：
中图分类号：P618.41;P618.65
文献标志码：
基金项目:本文得到中国科学院"百人计划"项目（编号：Y333081A07）、中国科学院创新交叉合作团队项目（编号：Y433131A07）和矿床地球化学国家重点实验室开放课题（编号：201508）联合资助
引用文本：
许超,陈华勇,Noel WHITE,祁进平,张乐骏,张爽,段甘.2017.福建紫金山矿田西南铜钼矿段蚀变矿化特征及SWIR勘查应用研究[J].矿床地质,36(5):1013~1038XU Chao,CHEN HuaYong,Noel WHITE,QI JinPing,ZHANG LeJun,ZHANG Shuang,DUAN Gan.2017.Alteration and mineralization of Xinan Cu-Mo ore deposit in Zijinshan orefield, Fujian Province, and application of short wavelength infra-red technology (SWIR) to exploration[J].Mineral Deposits36(5):1013~1038
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