【摘要】 贵州西部中、上二叠统界线附近普遍存在不整合面,在不整合面上往往发育厚度不等的风化壳。风化壳主要可归纳为三种类型:茅口组顶部的喀斯特漏斗、洼地中堆积的红粘土风化壳,锰质(铁质)风化壳,峨眉山玄武岩喷发间断面上或玄武岩顶部与龙潭组(宣威组)之间的的高铝高岭石风化壳。喀斯特侵蚀面上的红土风化壳是红土型金矿的赋存层位,峨眉山玄武岩喷发间断面上的高铝高岭石风化壳是铜矿、铝土矿赋存层位,喀斯特侵蚀面上的锰质(铁质)风化壳是锰矿、铁矿赋存层位,而玄武岩顶部与龙潭组(宣威组)之间的高岭石粘土风化壳是稀土、硫铁矿、铝土矿赋存层位。中、上二叠统界线附近风化壳对金、铜、铝土、硫铁、锰和稀土有明显的控制作用。更多还原

【Abstract】 Ancient weathering crust developed well near the Middle-Upper Permian boundary. According to lithology and mineralization,contract relationship between the weathering crust and overlying and underlying strata,the authors suggested that ancient weathering crust near the Middle-Upper Permian boundary may divide into three types: e.g.(1) basalt-lateritic weathering crust of karst-type overlying the Maokou Formation(limestone);(2) manganese and iron weathering crust of karst-type overlying the Maokou Formation(limestone);and(3) tuff-weathering crust(kaolinite) between two basalt erupting episodes,with high contents of Al and kaolinite,or tuff-weathering crust(kaolinite) between basalt and the Longtan Formation/Xuanwei Formation.The basalt-lateritic weathering crust contains abundant lateritic gold deposits,and tuff-weathering crust(kaolinite) between two basalt erupting episodes common contains copper deposits and bauxites,and tuff-weathering crust(kaolinite) between basalt and the Longtan Formation/Xuanwei Formation commonly contains rare-earth deposits,pyrite deposits, bauxites and manganese deposits.Therefore,ancient weathering crusts near the Middle-Upper Permian boundary play an important role in mineralization of gold,copper,bauxites,pyrite,manganese and rare-earth deposits.更多还原