太行山北段砂页岩型铜矿地质特征及其意义

Geological characteristics and significance of sandstone-shale copper deposits in the northern section of Taihang Mountain

太行山北段发育大量寒武系馒头组紫红色岩系,但一直未有砂页岩型铜矿的报道。本次在山西省广灵县上麻地沟一带发现砂页岩型铜矿,赋存在寒武系馒头组上部灰绿色页岩中,经探槽揭露,出露厚度一般为0.21~0.65m,品位变化为0.11%~0.58%。含矿层分布面积可能超17 000 km;。广泛发育的含矿层,和相对稳定的厚度、品位、矿化层位,暗示本区砂页岩型铜矿为沉积成岩时形成。灰绿色含铜页岩因富含有机质和Fe;为还原层,可作为地球化学障使含矿热液发生沉淀富集,同时岩浆热液也可以萃取原矿化层中的铜使其进一步富集,这为本区已知岩浆热液矿床找矿提供一个新的思路。

A large number of Cambrian Mantou Formation purplish red rocks developed in the northern section of Taihang Mountain, but there have been no reports of the sand-shale type copper deposit. This time, a sand-shale type copper deposit was found in the Shangmadigou area, Guangling County, Shanxi Province,Which occurred in grey green shale of the upper Cambrian Mantou formation. The thickness of the exposed shale was 0.21 m~0.65 m, and the grade change was 0.11%~0.58%, as revealed by the exploratory trench. It is found that the distribution area of the ore-bearing layer maybe exceeds 17000 km;. The extensively developed ore-bearing layers, and relatively stable thickness, grade, and mineralized layers suggest that the sand-shale copper deposits in this area were formed during sedimentary diagenesis. The ore-bearing layer, rich in organic matter and Fe;, is a reducing layer, which can serve as a geochemical barrier to precipitate and enrich the ore-bearing hydrothermal fluid. At the same time, the magmatic hydrothermal fluid can also extract copper in the original mineralized layer to further enrich it. This provides a new idea for prospecting known magmatic hydrothermal deposits in this area.