Geochemistry of Trace Elements in Bauxite of China Lia Changling Qin Zhian

The contents of most trace elements, especially B, Ga and Zr, in Bauxite of China, are higher thanthe means of that in the Crust, but those of Cu, Ba, Rb, Sc etc. are lower. Compared with othertquntries, the bauxite of China is obviously richer in Zr, Ga, Sr, Ba, B, Ni, Cu, Nb, poorer in Cr,V etc.The contents of more active elements (such as B, Sr, Ba, Rb) distribute in a wide range and thefrequency decreases quickly with the increase of the contents.The contents of stable Zr, Cr and Ga are nearlyof normal distribution. The gibbsitic bauxite formed by weathering of basalt in south-eastern China obviously reflects the fea-tures of basalt, that is rich in Cr, Co, Sc and poor in Zr, Ni. The diasporitic bauxites formed bysedimentation in different areas also have their own features, those on Yangtzi platform rich in Ga; insouthwestern Guan脚and south-eastern Yunan rich in Zr, Cr; in Kangdian axis of earth rich in V, Zr;on North China platform rich in B, Sr, Ba, Ni. From north to south the contents of V and Cr are in thetendency of increasing. The contents of trace elements in bauxite is related to basal rocks, one of the reason is that some basalrocks are the source rocks, or the two have similar mother rocks, the other is that the movement of some e1-ements takes place due to ground water in diagenesis and supergenesis.The content of Ga in bauxite decreases with the time passing.C₁and P₁ bauxite are rich in Ar, Cr andV.C₂ bauxite rich in B, Zr, Sr.The wntents of trace elements in Mz bauxite are low, in Kz bauxite, Crcontent is very high, and those of Zr, Co and V are high. In different rocks, the ratios of pairs of tracx elements or with the content of A1₂20₃ are different be-cause of their different geochemical properties, sources and formations of the rocks. According to the distribution of trace elements and their ratio in bauxite, compared with basal rock, itfound that the gibbsitic bauxite in southeastern China inherited the feature of its mother rock (basal basalt)in trace elements, withe the relative contents of Zr, Cr, Ga, and Ga/A1203value; the sedimentary baux-ites in Xiuwen, Tuanzi and Zhangjiaquan mainly originate from their basal rock: those in Pinguo, Xiaoyiand Xinzhan mainly from Al-silicate of acient continents.