滇黔桂卡林型金矿区水系沉积物和岩石金含量与时空分布

The Concentrations and Temporal-spatial Distribution of Gold in Stream Sediments and Rocks in the Carlin Type Gold Ore Districts of Yunnan–Guizhou–Guangxi Region

为研究滇黔桂卡林型金矿区水系沉积物和岩石中金的地球化学时空分布及其与金矿规模的对应关系,系统收集了该区1:20万区域化探全国扫面计划水系沉积物和全国地球化学基准计划岩石金的地球化学数据,绘制了水系沉积物和岩石金的地球化学分布图。滇黔桂卡林型金矿区以水系沉积物金地球化学异常面积大于1000 km^2为准,共圈定5处金的地球化学省,这些金的地球化学省同时也是矿床大规模产出的部位。区内右江盆地水系沉积物金背景值(1.94×10^–9)高于扬子克拉通(1.68×10^9),其内以泥岩、页岩、砂岩、灰岩为代表的容矿岩石金背景值(0.51×10^–9)也高于扬子克拉通(0.39×10^–9)。研究区不同构造单元及沉积相中水系沉积物金背景值受岩石金背景值的制约。金的地球化学省是地壳演化过程中不均匀分布的高金背景岩石、金矿化作用及金矿床次生风化作用相互叠加的结果。该研究有助于有效判断异常成因、识别成矿作用存在,对研究金的区域成矿规律和聚焦找矿靶区具有重要意义。

In order to study the temporal-spatial distribution of gold resources in stream sediments and rocks and their spatial relationship with known reserves of gold deposits in the Carlin-Type gold ore districts of Yunnan–Guizhou–Guangxi region,the authors compiled geochemical distribution maps of gold in stream sediments and rocks based on geochemical data collected from 1:200000 Regional Geochemistry-National Reconnaissance Project and China Geochemical Baselines Project.Five gold geochemical provinces with an area of over 1000 km^2 were delineated,which are spatially consistent with the distribution of the Carlin-Type gold deposits in this area.There are relatively higher gold background values in stream sediments and ore-hosting rocks(mudstone,shale,sandstone,limestone)in the Youjiang Basin(1.94×10^–9,0.51×10^–9)than the values of the Yangtze craton(1.68×10^–9,0.39×10^–9).The gold background values of stream sediments are constrained by those of rocks in various structural units and sedimentary facies in the study area.Gold geochemical provinces might have resulted from the mutual superposition of the rocks with high gold background value,gold mineralization,and secondary weathering of gold deposits.The results obtained by the authors contribute to judging the genesis of anomalies and identifying the existence of metallogenesis effectively,and play a key role in exploring the regular pattern of gold regional metallogeny and delineating prospecting targets.