戈壁覆盖区金窝子矿带深穿透地球化学方法研究

DEEP PENETRATION GEOCHEMISTRY METHODS IN GOBI-OVERBURDEN TERRAIN OF THE JINWOZI METALLOGENIC BELT

文章以金窝子金矿带为例,讨论戈壁覆盖层的分带结构,以及金等成矿元素在干旱景观区的表生迁移和矿化信息的传递机制;试验研究了本区土壤和活动态测量等深穿透方法效果,提出了戈壁覆盖区化探勘查和找隐伏矿的技术方法。通过重点剖面和1200km2面积1∶20万比例尺的多指标地球化学测量证明,戈壁覆盖层主要由坡-冲积层和冲-洪积层互层构成,其中坡-冲积层属当地风化产物,包含矿化信息;而冲-洪积层为运积物。土壤(-160目)测量对于圈定区域金成矿构造带和显示出露矿化效果良好,应用水提取态和铁锰氧化物态等深穿透指标,可以揭示覆盖金矿化。

This paper deals with composition, structures and genesis of Gobi-overburden and transmission mechanism of mineralization information in dry landscape area as an example of Jinwozi gold metallogenic belt. The prospecting effects of some deep-penetration methods as soil, vapor-mercury and mobile forms of metals surveys have been tested in areas of 1200 km^2 at scale of 1∶200000. A multi-indicator geochemical exploration technique for prospecting the overburden mineralization in Gobi- overburden has been developed. By means of experimental survey and geological section investigation, it is demonstrated that Gobi-overburden is formed mainly from interbedding of the eluvium-slope wash and alluvial-flood deposit layers. The eluvium-slope wash layers are results of local bedrock weathering and contain mineralization information, and alluvial-flood deposit layers present a transported overburden. They both underwent the processes of gobization, and form a specific vertical zone-structure with Ca-deposit (mainly gypsum) layer. The soil survey with a sampling <160 mesh fractions give a perfect results for location of regional tectonic metallogenic belt, and indication the output mineralization. Using deep-penetration mobile form indicators (water extraction form and metal form with Fe-Mn oxides) may be delineates overburden gold mineral deposits.