卫宁北山多金属矿构造岩相成矿规律与找矿研究

Study of the tectono-lithofacies mineralization regularities and prospecting of the molymetallic deposit in Weiningbeishan

卫宁北山地区是宁夏境内最具有勘查前景的金属矿成矿区之一,具有得天独厚的成矿地质背景和良好的成矿条件。目前,该区已做了大量的基础工作,研究成果众多,但是找矿工作一直没有取得重大突破。本文以含矿建造-构造-成矿综合研究为主线,综合前人研究成果,深入分析了卫宁北山多金属矿的成矿规律,探讨了矿床成因类型,建立了找矿标志。以中上奥陶统的各类建造为基础,其上沉积了较厚的泥盆系和石炭系碎屑岩建造和碳酸盐岩建造,而多金属矿就产于石炭系前黑山组和土坡组的灰岩和砂岩中,为主要的赋矿地层。三叠纪末期的印支运动,形成了以SN向挤压为主近EW向展布的断裂和褶皱,控制了卫宁北山地区的构造格局和演化以及多金属矿的空间分布,而矿体主要产于较大构造破碎带的次一级构造中,构造控矿明显。多金属矿的形成与燕山期中酸性岩浆的侵入密切相关,为中-低温热液矿床。依据上述成果,指出了卫宁北山找矿方向和有利区段。

The Weiningbeishan is one of the most promising metallogenic deposits in Ningxia,which has advantaged geological background and favorable metallogenic conditions.At present,the area has been explored and studied for many years,but there has been no major breakthrough for prospecting.Taking the synthetic study of formation-tectonics-mineralization as the basic way of thinking,the metallogenic regularities of polymetallic deposits is analyzed,the genetic type of deposit is discussed,and the prospecting sign is established.With the middle-upper Ordovician series as the sedimentary formational basis,the thick Devonian and Carboniferous clastic rock and carbonate formation was developed on it,and the polymetallic ore is found in the limestone and sandstone of the Tupo and Qianheishan formaion in Carboniferous series which is the main mineralization strata.The Indosinian movement in the late Triassic period,the extension direction of fracture and fold formed by the south-north extrusion was east and west,which not only controlled the tectonic framework and evolution of the Weiningbeishan,but also controlled the spatial distribution of polymetallic minerals.The ore body is mainly produced in the subgrade structure of the larger structural fracture zone,which is controlled by the structure obviously.The formation of polymetallic ore is closely related to the intrusion of acidic magma in Yanshan period,and the genetic type of deposit is medium-low temperature hydrothermal deposit.On the basis of above mentioned results,the prospecting direction and favorable segments for prospecting in the Weiningbeishan can be proposed.