| 其他摘要 | Bauxite refers to a kind of ores which can be refined as aluminum oxide in the metallurgical industry in the current technical conditions, and then electrolysis into aluminum metal. The bauxite of Guizhou is rich and it is the second largest bauxite producing areas which occupy the whole bauxite sources of 17% in China. In the course of studying, we have used the laboratory data of the major elements, trace elements and rare earth elements, also, with the geological characteristics and previous data to analyze the geological characteristics of the deposit, geochemical characteristics, the forming environment, ore structure, mineral composition and mineral deposit genesis in the Xiao Shan Ba deposit of Xiuwen county, Gou Jiang deposit of Zunyi county, Huan Da Yan deposit of Daozhen county and the Yu Dong deposit of Kaili. To sum up, come to the following results: (1) the bauxite mainly distribute in two epochs which are the late Carboniferous and middle Permian. Ore-hosting stratum can be divided into two sections: the lower ore-hosting rock series of the iron, and the upper ore-hosting rock series of the aluminum. The overlying strata of the Ore-hosting stratum are the Lower Carboniferous and Permian. The underlying strata are the Cambrian, Lower Ordovician, the Devonian and Upper Carboniferous. The underlying strata provided the mineral sources and places for accumulation, except for the underlying layers of the Zhengan-daozhen belt belongs to the peneplain landform which the composition is made by the mudstone and shale, and the others belong to the ancient karst weathering surface. ( 2 ) The natural type of bauxite mainly consist of classic, pisolitic, oolitic in Xiao Shan Ba deposit of Xiuwen county, the other three deposit mainly consist of earthy, also part of oolitic, half earthy, massive. The industry type of bauxite mainly consist of the low iron and low sulfur, also there are the high iron and low sulfur type, the high iron and high sulfur type and the high sulfur and high iron type. ( 3 ) The mineral mainly compose of the diaspore, also, there is boehmite, gibbsite in some place; the chemical components have Al2O3、SiO2、Fe2O3、S、CaO、MgO、K2O、Na2O、H、CO2、Li2O、Ga、Zr、Ba、Sr、Cr、V、Sc、B、Ni，Ce、Ta、Rb、REE and so on, the four maximum elements is Al2O3、SiO2、Fe2O3 and TiO2, other remaining elements is less than 1% . ( 4 ) The trace elements just like as the Zr, Hf, Ta, W, Th, U are higher than the content of NASC, in addition to the Huan Da Yan deposit of Xiuwen county, while the Co, Rb, Sr, Sb, Ba are lower than the content of NASC. While the Sc, As, Sr, Pb is equal to the NASC in the four county. ( 5 ) In all bauxite deposit, Al2O3 showed a positive correlation with TiO2, Al2O3 and SiO2, Al2O3 and Fe2O3 showed a negative correlation. these characteristics fully explain the bauxite mineralization is a process of collection in aluminum and leaching out of iron and silicon in the same time. Nb and Ta, Zr and Hf show a positive correlation which indicate the parent rock of the bauxite have experienced a more adequate homogenization, and the origin of the parent rock keep a good consistency. ( 6 ) The underlying strata in the Xiao Shan Ba deposit of Xiuwen county may be a major source of material bauxite; the major source of material bauxite in the Gou Jiang deposit of Zunyi county may be from other place; the major source of material bauxite in the Huan Da Yan deposit of Daozhen county may be from the Hanjiadian group of the lower Silurian series; The underlying strata in the Yu Dong deposit of the Kaili county may be relevant to the formation of the bauxite, but may be come from the other place. ( 7 ) The REE patterns of the ore-hosting strata in Xiao Shan Ba deposit of the Xiuwen county is rich in LREE, Eu(Eu*=0.85) and Ce(Ce*=0.75) anomaly are negative; The REE patterns of the ore-hosting strata in Gou Jiang deposit of the Zunyi county is rich in HREE, Eu(Eu*=0.85) anomaly is negative, Ce(Ce*=1.15) anomaly is positive; The REE patterns of the ore-hosting strata in Huan Da Yan deposit of the Dao Zhen county is rich in HREE, Eu(Eu*=1.19) and Ce(Ce*=1.68) anomaly are Positive; the REE patterns of the ore-hosting strata in Yu Dong deposit of the Kaili county is rich in HREE, Eu(Eu*=0.87) anomaly is negative, Ce(Ce*=1.13) anomaly is positive. According to the analysis above, we can know that the formation of bauxite is an oxidizing environment except the Xiao Shan Ba deposit of the Xiuwen county. ( 8 ) The formation of deposit: Guizhou located in the vicinity of the equator in Carboniferous and Permian, the climate is tropical , hot and humid. It is easy to form bauxite substances, and then migrate to the low-lying aggregate to form a certain scale, after undergone supergene enrichent stage, it formed the weathering crust bauxite. The indicator of the bauxite have the ancient erosion section sign, folds, geomorphology sign, coal and irons sign, bauxite signs. |
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