河南省新安县郁山隐伏铝土矿成因分析

摘 要]通过对河南省新安县郁山铝土矿床成矿时代、成矿物源、成矿环境、控矿因素等分析,认为郁山铝土矿床成矿时代为早二叠世,成矿物源主要为古陆铝硅酸岩风化物,少量为豫西中奥陶统马家沟组碳酸盐岩风化产物,成矿环境为渑池泻湖东北边缘的潮坪-沼泽环境,由长期的沉积间断、特定的岩相古地理特征、构造变形和表生风化作用共同控制矿床的形成。认为郁山铝土矿床的形成经历了“三期五阶段冶:“三期冶包括铝土矿体就位、埋藏、改造保存三个成矿时期;具体可划分为“五阶段冶,包括物源准备和搬运、同生、成岩、后生、风化和表生五个成矿阶段。提出了郁山铝土矿矿床为“古陆风化+碎屑和化学沉积冶的成矿模式。其主要成矿机制为机械和化学分异。

Genesis of the Yushan Concealed Bauxite Deposit in Xin'an County, Henan Province

This paper analyzed the metallogenic epoch,ore-forming material source,metallogenic environment,and ore-controlling factors of the Yushan bauxite ore deposit in Xin’an County,Henan Province.It is suggested that the Yushan bauxite ore deposit formed in the early Permian.Its ore-forming material sources are weathered products,which mainly came from aluminum silicate rocks of the paleouplift,and a small mount were derived from the underlying Middle Ordovician Majiagou Group carbonate rocks in western Henan Province.Metallogenic environment was the tidal flat-wetland environment of northeast edge of Mianchi lagoon.The long-term sedimentary intermittence,specific lithofacies-paleogeographic characteristics,structural deformation and supergene weathering controlled the formation of the deposit jointly.It is considered that ore-forming process of the Yushan bauxite ore deposit has experienced three periods and five stages.The three periods are ore body emplacement,burial,transformation and preservation;the five stages are material source preparation,transportation,syngenesis,diagenesis,deuterogenic stage,weathering and epigenesis.A metallogenic model of bauxite(clay) deposits as "paleouplift weathered + clastic and chemical deposits" is put forward.Its principal metallogenic mechanism is mechanical and chemical differentiation.