黔西南卡林型金矿剥蚀程度评价

对黔西南卡林型金矿集区开展矿田、矿床 (点) 剥蚀程度研究，能为新一轮找矿勘查布局提供有力支撑.以热液渗滤晕分带理论为指导，依据区内金矿床原生晕在空间中存在分带性以及次生异常与金矿床在地表呈现总体无偏特征，构建了大区域尺度量纲中能总体反映成矿元素分散流与原生晕共性特征的元素分带序列，计算了基于序列中元素区域化探扫面数据多重分形奇异性分析的前缘元素与尾部元素地球化学强度“对比值”，研制了矿田及其附近以“对比值”数据结构为主体的“低-浅-中-高”4个级别剥蚀程度定量评价指标，并结合实地地质特征开展综合评价工作.给出区内10个矿田和15个主要金矿床 (点) 的剥蚀程度评价结果，总体显示出右江区矿田剥蚀程度低于扬子区，泥堡、紫木凼、水银洞、丫他、烂泥沟等中-特大型金矿床剥蚀程度皆为低-浅剥蚀，而资源量相对较小的板其、戈塘、老万场等金矿床剥蚀程度普遍偏高.在此基础上，通过戈塘与水银洞金矿的进一步地质比对，论证了评价结果逼进了勘查事实并可以扩展到区内有一定勘查程度的地区.此外，对评价结果的分析表明，“对比值”异常是寻求找矿突破和现有矿床 (点) 深部成矿预测的主要评价指标之一，对找矿勘查有重要指示作用.据此初步提出水银洞金矿床及其以东的深部、戈塘金矿床北西二叠系与三叠系接触带附近、上大观矿点深部等14处深部找矿潜力较大的地区. 

Evaluation of Denudation Degree of Carlin-Type Gold Deposits in Southwest Guizhou Province

The study of the denudation degree of the Carlin-type gold deposits (ore fields-ore deposits-ore occurrences) in southwest Guizhou Province could facilitate future exploration. Present research is based on hydrothermal halo zoning percolation theory, the general unbiased feature of the space between gold deposits and secondary anomalies as well as the mineralization zoning of the ore-forming elements. The sequence of element zoning which could reflect the common features of ore-forming elements dispersed flow and primary halos in regional scale dimension is firstly constructed.Then, the contrast values of geochemical strength between the front and rear halo in zoning sequence are obtained on the basis of singularity analysis of stream sediment geochemical dataset collected in this region. The evaluating indicators of denudation degree are established and classified into four different levels as low-light-medium-high according to the data structures of contrast values.In addition, the evaluating indicators are applied to comprehensive evaluation combined with the geological characteristics of deposits, ore fields and their surroundings. In this paper, the results of denudation degree related to the ten ore fields and fifteen major gold deposits are presented. Our research reveals that the Youjiang ore fields have lower degree of denudation than the Yangtze one. Furthermore, the degree of denudation is apparently positively correlated with the amount of resources.The medium to superlarge sized gold deposits such as Nibao deposit, Zimudang deposit, Shuiyindong deposit, Yata deposit and Lannigou deposit are characterized with the low-to light-denudation degree.While the relatively small sized deposits such as Banqi deposit, Getang deposit, Laowanchang deposit are with the high degree of denudation. The evaluation results are consistent with those of the previous exploration work and may be extended to the areas undergone basic prospection.In addition, it is found that the anomalies of the contrast value are the main sign of the evaluation for obtaining prospecting breakthrough and deep area ore-prospecting of existing deposits. Fourteen districts of deep ore with high prospecting potential are proposed in this study, including the Shuiyindong deposits and its eastern deep area, the contact zone between Permian and Triassic strata in the northwestern part of Getang deposit and the deep part of the Shangdaguan ore occurrence.