西藏日土县材玛铁矿地质特征及找矿方向

Geological characteristics and Ore-prospecting direction of the Caima iron deposit in Ritu County,Tibet

通过对西藏日土县材玛铁矿床的调查研究表明,南羌塘拗陷带的材玛铁矿床成矿地质条件较好。经地表槽探揭露和深部钻探工程控制,发现其矿体为似层状;矿体品位和厚度沿走向和倾向变化较小;容矿岩石主要为矽卡岩、矽卡岩化灰岩;矿石类型简单,主要为磁铁矿矿石。矿化富集与侵入于上三叠统地层的燕山晚期花岗闪长岩、二长花岗岩、花岗斑岩密切相关;矿体产出部位严格受碳酸盐岩层位及其层间破碎带的控制,属接触交代型矿床。其形成与燕山晚期岩浆活动关系密切,空间分布严格受岩浆岩和断裂的控制。花岗岩类岩体与上三叠统地层的接触带和层间破碎带是寻找铁矿的有利部位,外围地区具有寻找相同类型铁矿床的远景。

Abstract：Basing on the investigation and research on the Caima iron deposit in Ritu County, Tibet, it has been ascertained that the Caima iron deposit in the South Qiantang geotectogene possesses fine minerogenic geological conditions. The uncovering by ground trenches and deep coutrolling by drilling show that the ore bodies have a stratoid form, the grades and thicknesses of ore bodies are slightly varied along their strikes and inclinations, the host rocks mostly are skarns and skarnized limestones pie mainly belonging to the magnetiteore, The minerogenic concentration is close the ore types are sim related with the late Yanshanian granodiorites, monzogranites and granite porphyries intruded into upper Triassic strata, the occurrence positions of ore bodies are strictly controlled by carbonatite beds and intebedded fracture zones, belonging to the contact-metasomatic type deposit, its formation is closely relateel to the late Yanshanian magmatic activity, and its space distribution is strictly controlled by magmatic rocks and fractures, therefore the contacts between granitoid intrusions and upper Triassic strata and the interbedded fracture zones are favourable positions for the iron ore-prospecting, and the periphery of the deposit is prospective for ore-prospeeting of the same type iron deposits.