黔中—川南石炭纪铝土矿的地层及成矿时代

本文从构造控矿角度,阐述了黔中—川南成矿带内铝土矿的分布特征,在此基础上,运用多重地层划分的概念,对铝土矿含矿岩系的岩石地层、生物地层及年代地层进行了初步探讨。铝土矿是加里东运动使下古生代地层隆起并暴露地表,经长期红土化作用,形成铝土矿成矿母质后,由于基底隆起和沉降时期的不同,自南向北,逐步沉积而成的。铝土矿的成矿时代是南部修文矿带最早,属早石炭世大塘期祥摆时至旧司时,中部的息烽矿带和遵义矿带可能为早石炭世大塘期至德坞期,北部的道真矿带大致为晚石炭世马平期。

THE CARBONIFEROUS BAUXITE-BEARING STRATA AND MINERALIZATION AGES IN CENTRAL GUIZHOU-SOUTHERN SICHUAN

From an angle of structural control of ore deposition, this paper deals with the distribution of bauxite in the central Guizhou-southern Sichuan metallogenic belt. On that basis, this paper preliminarily discusses the lithestratigraphy, biostratigraphy and chronostratigraphy of the bauxite-bearing rock series using the concept of multiple stratigraphic classification. Bauxite was formed by the following geologic process. The Caledonian movement caused Lower Paleozoic strata to uplift and outcrop on the ground surface. Through long-continued lateritization the mother material of bauxite was formed. As the time of basement upliit was different from that of subsidence, it was deposited gradually from south to north, thus forming bauxite. The mineralization age of bauxite is the earliest in the Xiuwen ore zone in the south, being from the Xiangba Chron to Jiusi Chron of the Early Carboniferous Datangian Stage; the mineralization age may probably be from the Datangian Stage to Dewu Stage of Early Carboniferous in the Xifeng ore zone and Zunyi ore zone in the central part and roughly the Late Carboniferous Maping Stage in the Daozhen ore zone.