摘要
对鞍山、冀东和五台铁矿集中区的航、卫片地质解译,认为前寒武纪沉积变质铁矿形成的古环境,皆为同心圆、椭圆状的环形构造。距今3900～4100Ma,曾发生陨石雨事件。当时地壳较薄,陨石的巨大冲击力使地球表面断裂,诱发了拉斑玄武岩浆的喷溢,铁质相继随火山作用流出、沉积形成条带状铁矿。由于环形构造内火口繁多,提供的铁质也相对丰富。因此,在区域找矿选点评价时,除研究含铁建造沉积相外,在航、卫片上,大型环形影像,可作为寻找大型铁矿的靶区。
Based upon the geological interpretation of air and satellite photographs taken over the districtscrowded with iron deposits as Anshan,eastern Hebei and Wutai areas,it is noted that all the palaeo-environments for the formation of Precambrian sedimento-metamorphic iron deposits are ring structur-es,being concentric circles or ellipses in shape.Meteor shower events happened about 3900-4100 Ma agoexerted a tremondous impulsive force to the earth surface(at that time the earth crust is more thinnerthan it is at present)and led to many fractured zones and eruption or overflow of tholeiitic magma.Subsequently the iron-bearing ore-forming fluid erupted out as a result of volcanism and deposited asbanded iron ore.The calderas within a ring structure are quite a few in number and thus a huge amountof source material for iron deposits were provided.Therefore,in regional exploration(for targetselection and evaluation),in addition to studying the sedimentary facies of iron formation,the largeting shaped images recognized on air and satellite photographs may be considered as the targets forfinding large size iron deposits.
出处
《地质与勘探》
CAS
CSCD
北大核心
1992年第2期1-8,共8页
Geology and Exploration
