摘要
作为世界上重要的金矿床类型之一,造山型金矿床一直受到国内各地勘单位和企业的广泛关注。然而,由于覆盖区广泛分布以及传统勘查方法的局限性,该类型金矿床的矿脉定位在勘查过程中面临较大挑战。近年来,大比例尺地质-光谱填图作为一种新兴的勘查技术,通过识别蚀变矿物分带及特定矿物光谱参数的系统变化,已在斑岩、VMS和浅成低温等成矿系统中得到广泛应用,并取得显著成效。本研究以东昆仑沟里金矿集区北部新发现的色日金矿床为研究对象,旨在探讨大比例尺矿物-光谱填图在覆盖区造山型金矿床中的应用效果。通过该方法,不仅揭示了潜在矿脉分布及深部含矿热液通道,还提取了与矿化相关的光谱特征,为成矿靶区圈定提供依据。研究结果表明,色日金矿床的金矿化晚于矿区岩浆活动,主要富集Au-As-Cu-Pb-Zn元素,其矿化样式包括石英脉型和蚀变岩型,矿脉严格受构造控制,具有典型的造山型金矿地质特征。此外,金矿脉与中基性脉岩存在密切的空间关系。通过短波红外光谱(SWIR)分析,识别出四种主要含水蚀变矿物,即白云母族、绿泥石、高岭石和蒙脱石。镜下观察显示,金矿化主要与白云母密切相关,因此进一步利用白云母族Al-OH吸收峰位(Pos2200)、IC值(白云母族在2200 nm处吸收峰深度与1900 nm吸收峰深度的比值)进行研究,发现成矿期热液蚀变在特定部位表现出高Pos2200、高IC值的特征,并结合品位分布规律,揭示了可能的深部热液通道。在此基础上,提取白云母族参数,即高Pos2200(Pos2200>2203.1)或高IC值(IC>1.6),作为光谱勘查标识。结合本次大比例尺填图获得的蚀变石英脉分布及中基性脉岩群分布特征,圈定了三个潜在成矿靶区。本研究为矿物勘查方法在金矿中的应用提供实例,也为东昆仑地区造山型金矿的进一步找矿勘查突破提供新的思路和技术支持。
As the most significant type of gold deposits,orogenic gold deposit have consistently been a primary focus of exploration.However,extensive regolith cover and limitations of conventional exploration techniques pose challenges for pinpointing orebody locations.Recently,large-scale geological and spectral mapping has proven effective in porphyry,VMS,and epithermal ore systems.In this study,we apply this approach to locate deep hydrothermal channels and identify hidden orebodies.Gold mineralization postdates magmatic activity and is characterized by the enrichment of Au-As-Cu-Pb-Zn.It is also structurally controlled,encompassing vein-to disseminated-type ores.These field geological features and mineral assemblages are consistent with the characteristics of orogenic gold deposits.Additionally,orebodies are predominantly hosted near or within mafic rocks.Approximately 570 surface samples and 450 drill core samples were analyzed using an SWIR instrument.Four types of alteration minerals were thus identified:white micas,chlorite,kaolinite,and montmorillonite.Microscopic petrographic observations reveal that white mica is closely associated with gold mineralization.When combined with gold grade distribution,the Al-OH absorption wavelengths of white micas at 2200 nm and IC values(the ratio of the depth of the~2200 nm minima to the~1900 nm minima)show a distinct increases at specific locations,indicating potential hydrothermal channels.Pos2200>2203.1 nm or IC>1.6 can serve as spectral indicators for mineralized zones.Three target areas were delineated using these spectral indicators,together with the distribution of quartz veins and mafic dyke swarms.This study provides a practical example of applying mineral exploration methods to gold deposits and highlights the significant potential of this approach for greenfield exploration of orogenic gold deposits in the Eastern Kunlun.
作者
汪浩
李华
陈华勇
张正虎
于小亮
曹根深
WANG Hao;LI Hua;CHEN Huayong;ZHANG Zhenghu;YU Xiaoliang;CAO Genshen(State Key Laboratory of Deep Earth Processes and Resources,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China;Qinghai Provincial Geological Survey Bureau,MNR Technology Innovation Centre for Exploration and Exploitation of Strategic Mineral Resources in Plateau Desert Region,Xining 810000,Qinghai,China;Guangdong Provincial Key Laboratory of Mineral Physics and Minerals,Guangzhou 510640,Guangdong,China;The Third Nonferrous Geological Exploration Institute of Qinghai Province,Xining 810012,Qinghai,China)
出处
《大地构造与成矿学》
北大核心
2026年第1期76-90,共15页
Geotectonica et Metallogenia
基金
青海省省级地质勘查专项资金项目(2023085029ky004)
国家重点研发计划项目(2022YFC2903301)联合资助。
关键词
大比例尺
地质-光谱填图
色日金矿床
造山型金矿床
成矿靶区
large-scale
geological and spectrum mapping
Seri gold deposit
orogenic gold deposit
target delineation
