Geological Features And Analysis Of Genesis Of Moeng Manganese Ore Deposit In Botswana

Abstract:On the basis of the latest exploration results, field geological survey, collection and testing of sample, and drawing and research of comprehensive maps, this paper systematically summarizes the regional geological setting of the area, and the geological characteristics of the manganese deposit. On this basis, this paper analyses the depositional environment and subsequent transformation of the manganese deposit, and sets up the genetic model of this manganese deposit. The main achievements are made as follows:1. The paper points out that the Moeng manganese is controlled by the Limpopo mobile belt which resulted from the pressing between the Kaapvaal Craton and the Zimbabwe Craton during the period from3.27billion to2.6billion years.The Moeng manganese ore deposit is closely associated with iron-formation, which is strictly controlled by the rift groove that developed the southern margin of Limpopo mobile belt.2. Moeng manganese are mainly oxidized manganese ore and manganese carbonate ore. Manganese oxide ore are distributed at the surface and near-surface. The ore minerals are mainly hollandite, secondly pyrolusite. The gangue minerals are mainly quartz and hematite. Manganese oxide ore are formed by oxidation of manganese carbonate ore. The distribution of manganese carbonate ore are below the oxide boundary.3. The deposit is in a neritic sedimentary environment. The deposited material is likely to come from a denudation of the early Waterberg Group. The manganese deposit should be the initial deposition. With the tidal or storm flow, the initial deposited manganese was reactivated and deposited as the final diagenetic mineralization.4. Palapye group strata deposition may occur after the regional metamorphism, with not very strong metamorphism; the manganese layer was lifted to the surface, as a result, the surface and near-surface manganese ore was all oxidized, the oxidation range extending about225m in tendency.5. The present writer draws a preliminary conclusion that the the original manganese layer is neritic sedimentary metamorphic manganese deposit, and that surface and shallow layer is "manganese cap type" manganese oxide deposit. The comparison between Moeng manganese ore deposit and Kalahari manganese ore field, the largest in the world, shows that these two manganese ore deposits have similarities in metallogenic background, metallogenic epoch, ore deposit features, lithofacies paleogeography, and epigenetic modification, which leads to a conclusion that Moeng manganese deposit has the potential for a large-scale manganese ore deposit.