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

Luo Diwei; Yao Shuzhen; Wang Chengxiang; Zhang Huanchao; Ji Guosong

doi:10.3799/dqkx.2016.016

Abstract：The study of the denudation degree of the Carlin-type gold deposits (ore fields-ore deposits-ore occurrences)in south-west 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 el-ements dispersed flow and primary halos in regional scale dimension is firstly constructed.Then,the contrast values of geo-chemical 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 classi-fied into four different levels as low-light-medium-high according to the data structures of contrast values.In addition,the eval-uating 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.Further-more,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 character-ized 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 exist-ing deposits.Fourteen districts of deep ore with high prospecting potential are proposed in this study,including the Shuiyin-dong deposits and its eastern deep area,the contact zone between Permian and Triassic strata in the northwestern part of Get-ang deposit and the deep part of the Shangdaguan ore occurrence.