摘要
中国的干旱荒漠戈壁区，约占国土面积的1/4。自然特点是极其干旱，沙漠和戈壁广布，土壤呈碱性。大部分面积尚未进行区域化探扫面工作，即使进行工作的地区，由于风成沙和土壤碱性的影响，结果并不理想，难以了解整个地区资源潜力。超低密度地球化学方法经过近10年发展，已经显示它不受地表覆盖物影响，能够快速有效地圈定战略靶区。因此，超低密度地球化学方法被用于东天山1.5×105 km2的调查试点研究，发现弱胶结层是干旱荒漠区超低密度调查的有效采样介质，并且深部含矿信息主要赋存在细粒级部分和氧化地球化学障中，使用细粒级部分与提取氧化物膜中的金属元素相互补充可以有效地识别含矿信息。使用超低密度地球化学方法可以达到迅速、有效圈定有利于大型矿床或矿集区战略靶区的目的。通过1.5×105 km2地球化学调查，制作了30余种元素地球化学图，填补了东天山部分地区地球化学空白。新发现远景Cu、Au、U和W异常10余处，并发现东天山存在3条Cu异常带：东天山北带、中带和南带，其中土屋铜矿和黄山铜镍矿都位于中带，新发现的维权铜矿位于南带，北带还有待于进一步证实。相信这些异常的发现，对今后整个东天山矿产勘查的战略部署具有重要意义。
Northwestern China is a large unexplored or under-explored arid desert terrain, making up 22 % of total China's land territory. Into the new century, interest was rekindled by the discovery of a large porphyry copper deposit with copper reserves of more than 10 millions of tons in the eastern Tianshan mountainous belt, Xinjiang. In order to quickly get an overview of the mineral potential of the entire eastern Tianshan terrain, a large wide-spaced geochemical survey project was commenced in 1999 in area of 150 000 km2. Regolith sediments concealing prospective bedrock sequences cover the substantial area. The regolith sediments include alluvium, residuum, and windblown sand and caliche horizon. Soil geochemical methods (total analysis) and deep-penetration geochemical methods (selective leaching of mobile metals) are both used. The orientation study shows that wide-spaced sampling of the cemented sand can delineate large and clear geochemical patterns generated by metallogenic belts. The anomalies using selective leaching of mobile metals onto oxide coatings of cemented sand have greater contrast than those using total analysis. Wide-spaced sampling was carried out in an area of approximately 150 000 km2 at density of one sample per 100 km2. Soil samples were collected from the weakly cemented sandy horizon at a depth of 20-30cm. The soil samples were subjected to total analysis and selective leaching of mobile metals. Thirty elements were determined by ICP-MS, GF-AAS and AFS. Geochemical atlas and interpretation geochemical maps using GIS were generated. The results not only give prominent expression to the known metallogenic belts but also show new large-scale geochemical patterns of copper, gold, uranium and tungsten.
出处
《新疆地质》
CAS
CSCD
2001年第3期200-206,共7页
Xinjiang Geology
基金
中国地质调查局国土资源大调查项目(F321)资助
关键词
天山
荒漠戈壁区
地球化学
调查
评价
金
铜
铀
钨
the eastern Tianshan of northwestern China
arid desert terrain
wide-spaced
geochemistry
survey
jevaluate
