鲁西临沂一带三山子组分布及熔剂用白云岩成矿特征

Distribution of Sanshanzi Formation and Metallogenic Characteristics of Dolomite for Flux in Linyi Area in Western Shandong Province

摘要:

奥陶纪三山子组是鲁西熔剂用白云岩产出的典型层位，而潍坊临沂地层小区是三山子组最广泛发育区。本文在查明临沂地区三山子组呈“四个岩带”状分布的基础上，快速“锁定”熔剂用白云岩找矿区，于4个岩带中各选定典型矿区，以探矿工程和分析测试数据为依据，总结临沂地区三山子组熔剂用白云岩成矿特征，为鲁西乃至华北地区熔剂用白云岩找矿提供参考。熔剂用白云岩矿体赋存于三山子组c段，矿体严格受地层控制，倾向NE、NW，倾角5°～40°。矿体厚度30.5～108.6m，与三山子组c段厚度呈正相关，呈现自北向南厚度渐次变薄的规律。矿体中夹石不发育，矿体顶板为三山子组b段白云岩，直接底板为三山子组c段底部含燧石结核白云岩或薄层泥质白云岩。矿石质量稳定，MgO平均含量分别为20.23%~20.74%，夹石少，易于露天开采，具有良好的开发前景，预测远景资源量大于2亿t。

Abstract:

The Ordovician Sanshanzi formation is a typical layer produced by dolomite for flux in western Shandong province, while WeifangLinyi area is the most widely developed area of Sanshanzi formation. On the basis of identifying the distribution of Sanshanzi formation in Linyi area in the form of "four rock belts", prospecting target of dolomite for flux has been quickly locked. Selecting typical mining areas in each of the four rock belts, based on exploration engineering and analysis data, mineralization characteristics of dolomite for flux in Sanshanzi formation in Linyi area have been summarized. It will provide some references for the prospecting of dolomite for flux in western Shandong province and even northern China. The ore bodyies dolomite for flux is located in section c of Sanshanzi formation. The ore body is strictly controlled by the strata. The trend is NE and NW, and the inclination angle is 5°~40°. The thickness of the ore body is 30.5~108.6m. It is positively correlated with the thickness of section c of Sanshanzi formation, and shows a gradually thinning pattern from north to south. The rock is not welldeveloped. Roof of the orebody is composed of dolomite from section b of Sanshanzi formation, and the direct floor is dolomite containing flint nodules or thin layer argillaceous dolomite from section c of Sanshanzi formation. The ore quality is stable. The average content of MgO is 20.23%~20.74%, with few inclusions and easy openpit mining. It has good development prospects and is predicted to have a prospective resource of over 2 billion tons.