“华北地台”斑岩钼矿“成矿”侵入体地质特征

THE GEOLOGICAL CHARACTERISTICS OF THE “ORE-FORMING” INTRUS IONS OF“NORTHCHINA PLATFORM”

本文在对附近40个斑岩钼矿床(矿点)及+数个斑岩铜矿床岩石学和岩石化学统计计算的基础上,将“华北地台”钼矿床“成矿”侵入体分为花岗岩——流纹岩系列和花岗闪长岩系列。据“华北地台”斑岩钼矿侵入体的分布特征,产出的大地构造部位,围君时限(Ar—Pz)及厚度(>40KM),酸性岩的钼含量,钼本身的地球化学性质及同位素和稀土资料,对“华北地台”斑岩钼矿“成矿”侵入体的侵入构造环境,上侵方式,热液蚀变,有关的矿化类型和矿床构型以及钼的物质来源进行了探讨。指出“华北地台”钼矿斑岩体应属幔壳混合(过渡)型花岗岩系列。

Based on the petrology and the lithochemical statistical data from forty porphyry molybdenum deposits (prospects)and more than ten porphyry copper deposits,the“Ore-forming”intrusions of the porphyry molybdenum in the terrain of“North-China Platform”are tentatively divided into two systems:the granite and the granodiorite. On the grounds of the information about the distribution feature and the geotectonic situation of the intrusions,the goelogical time-range (Ar-Pz) and the thickness(over 40 KM) of the total surrounding strata disturbed by the intrusions,the Mo-content of the acidic intrusive bodies,the goechemieal behavaiour of the molybdenum itself as well as the available data of isotopes and rare-earth elements,this paper presents a discussion on several problems:the tectonic environment,the intruding-emplacing mode and the hydrothermal alteration of the intrusions,the possible types of Ore-mineralization and the regime of the ore-deposits induced by the intrusions,and the source materials of molybdenum ores as well. As a conclusion,this paper has pointed out that the ore-forming intrusions discussed should be the granite series of the mantle-crust (transitional) type