斐济红土型三水铝土矿床特征  

Laterite-type gibbsite depositcharacteristics in Fiji

作　　者：赵辛金 张启连 吴天生 陈海武 谢振朝 覃瑞才 ZHAO Xinjin;ZHANG Qilian;WU Tiansheng;CHEN Haiwu;XIE Zhenchao;QIN Ruicai(Geological Survey Institute of Guangxi Zhuang Autonomous Region,Nanning 530023,Guangxi,China)

机构地区：[1]广西壮族自治区地质调查院,广西南宁530023

出　　处：《矿产与地质》2021年第6期1054-1060,共7页Mineral Resources and Geology

基　　金：广西壮族自治区人力资源和社会保障厅“广西关键矿产资源深部勘查人才小高地”(桂组通字〔2019〕85号,2019—2023年)、广西壮族自治区地质矿产勘查开发局“桂西地区沉积型铝土矿控矿因素、成矿规律与找矿预测研究”(桂地矿综研〔2021〕85号)共同资助。

摘　　要：斐济红土型铝土矿产于平坦的火山盾边缘,矿层分布于起伏不大的高地和周围的低缓平台中。通过线路调查发现,风化壳由上部铝土矿层与下部的过渡层组成,自上而下具有红土型三水铝土矿典型的“Fe-Al-Si”变化规律,不同之处在于上部富铁铝土矿分层厚度薄,土状矿层中含有少量的风化母岩残砾;样品分析显示,矿石三水铝石相中w(Al_(2)O_(3))>40%。矿体除原地残积外,尚有坡积堆积成因,呈孤岛状分布;玄武岩、安山岩、火山碎屑岩、凝灰岩、泥岩等均可成为成矿母岩,但以玄武岩成矿最佳,其次为安山岩;另一种红土型铝土矿与磷矿共生,成矿母岩为安山质火山岩,Al、P呈反消长关系,属于洞穴堆积成因。该岛铝土矿地质特征研究有助于深化我国桂西地区二叠系铝土矿成因的认识。The laterite-type gibbsite deposits in FiJi are located on the edge of flat volcano shield,and the orebodies are distributed in slightly-undulating highlands and the surrounding low and gentle platforms.Through the route investigation,it is found that the weathering crust is composed of the upper bauxite layer and the lower transition layer.From the top to bottom,it has the typical"Fe-Al-Si"variation regularity of laterite-type gibbsite deposit,the difference is that the upper layer of iron-rich bauxite is thin,and the soil ore-layer contains a small amount of weathered parent rock residue gravel.The basic analysis of the sample shows that the ore gibbsite phase w(Al_(2)O_(3))is greater than 40%.In addition to the in-situ residual accumulation,the orebody also has the origin of slope accumulation,which is distributed in the shape of an island.Basalt,andesite,pyroclastic rock,tuff,mudstone,etc.can all become the metallogenic parent rock,but basalt is the best metallogenic rock,followed by andesite.Another laterite-type bauxite deposit and phosphorite deposit are symbiotic,and the metallogenic parent rock is andesite volcanic rock,Al and P are in an inverse relationship,which belongs to the origin of cave accumulation.The study of the geological characteristics of the bauxite deposits in Fiji will help to deepen the understanding of the origin of the Permian bauxite deposits in the West Guangxi,China.

关 键 词：红土型三水铝土矿 矿床特征 磷矿 斐济 

分 类 号：P618.45[天文地球—矿床学]