铀矿地质2026，Vol.42Issue(3)：440-451,12.DOI:10.3969/j.issn.1000-0658.2026.42.033
博茨瓦纳杰姆斯博克盆地砂岩型铀成矿条件与找矿远景预测
Metallogenic Conditions and Exploration Prospectivity of Sandstone-type Uranium Deposits in Gemsbok Basin,Botswana
摘要
Abstract
Gemsbok Basin lies in southwestern Kalahari Karoo Basin of Botswana and extends southwestward into Aranos Basin of Namibia.Because the two basins share similar tectonic settings,Karoo Supergroup stratigraphic frameworks,and sedimentary histories,the Wings sandstone-hosted uranium deposit in Aranos Basin provides a useful analogue for assessing uranium potential in Gemsbok Basin.This study evaluates the prospectivity of sandstone hosted uranium in Gemsbok Basin through integrated analysis of regional geology,stratigraphic correlation,palaeoflow patterns,representative boreholes,and fence sections.Wings deposit is hosted in Early Permian Auob Formation of Ecca Group and is controlled by a redox front.Mineralization is concentrated in Auob 3 sandstone aquifer,which is bounded above and below by coal-bearing strata and forms a characteristic mudstone-sandstone-mudstone configuration.In the Gemsbok Basin,the upper part of Otshe Formation is the closest equivalent to the ore-hosting interval of Auob Formation in terms of stratigraphic position,lithological association,and depositional facies,and is therefore considered the principal target horizon.Borehole data further indicate that Otshe Formation is best preserved in the northern part of the basin,suggesting that this area is the most favorable for uranium exploration.Interpretation of 12 boreholes from the northern part of the study area allows recognition of eight facies associations,of which Facies Associations 4 and 5 are the most favorable for sandstone-type uranium mineralization.Facies Association 4 represents delta-front sand bodies that likely acted as permeable aquifers and pathways for fluid migration,whereas Facies Association 5 comprises coal-bearing intervals that could have served as effective reducing barriers.Together,these units define the most prospective stratigraphic interval in the basin.Favorable conditions for uranium mineralization in Gemsbok Basin include:potential uranium sources in Precambrian basement and Damara Belt to the north and northwest;a gently inclined slope-belt structural setting along the northwestern basin margin further promoted the development of a groundwater recharge-runoff-discharge system;basinward transport of clastic material during Ecca deposition;the close spatial association between permeable sand bodies and coal-bearing reducing strata in the upper Otshe Formation.On this basis,a prospective mineralization area was preliminarily defined in the central-eastern part of the northern drill-controlled area,from ACP19—ACP13 area to the vicinity of MP1,with W3 forming the northern boundary.关键词
砂岩型铀矿/埃卡群/铀成矿条件/找矿预测/温斯矿床/杰姆斯博克盆地Key words
sandstone-type uranium/Ecca Group/uranium prospectivity/exploration targeting/Wings deposit/Gemsbok Basin分类
天文与地球科学引用本文复制引用
胡超男,钟军,宋继叶,王婷婷,范欣瑶..博茨瓦纳杰姆斯博克盆地砂岩型铀成矿条件与找矿远景预测[J].铀矿地质,2026,42(3):440-451,12.基金项目
核工业地质局铀矿地质科研项目(编号:地D2511)资助. （编号:地D2511）
