MINERALIZATION GEOLOGICAL CONDITIONS AND MECHANISM PROBLEMS OF BAUXITE DEPOSITS OF THE NOTH PART OF GUIZHOU PROVINCE

In the north of Guizhou the geological time of bauxites are early Permian, The some of them . (in the south of Zwenyi, Xifen and Kayang) are the type of accumulation in situ of crust of weathering their basements are clolomilite of Loshang 9 an group (∈_2-3) .Others (in the Zwenyi, Ongan and Zhenan, Daoahen) are the type of head of crust of weathering, their bed rocks are shale, silt with limestone of Tongxiu formatis (O₃) and Hanjiadion formation (S₂) .There are phenonmena of transition between ore deposits and bed rocks. The metterils of the bauxites origin the weathering of rocks under it.The thickness of disintegration reduce gradutly from south to north.Its 700-1OOOm in the south of Zwenyi, Xifen and Kayanf, 400-500m in the Zwenyi and Ongan, more than 200m in the Zhenan and Daozhen. In the study area, the weathering and disintegrats were from Caledonian to thfe middle of Idercynian.During this time, the crust elerats slomly, up to the early of Permian, the sea mater inter intrusted the study area.In Interral time of weatherding and disintegration is about 1-1.22 hundred M.Y., the time of formed latcrite is about 0.48 hundred M.Y. In this area, the characteristic of the bauxites are follows: 1. There are no parallel bcding, structures, textures formed in the water, no Zooliths and its fragments.Thcse imply the bauxites formed-under the atmosphere conditions.2.If bed rocks are shale, silt and other clastic rocks, so have phenomena of transition, i.e., the stratc which have beding gradualy change to the strata which have no beding from lower to upper. The phenomena of head in situ is quite'clear. If the bed rocks is carbonate, the change of the thinkness of ore body is obvious, generaly it's from less than one meter to several tens meters, the ore body formed in the dolines.In this condition, the ore body is little, its length is only several hundred meters and the wide is about 100-300m.3. Sometimes, the swamp developed during the time of bauxite formed, hence, there arc the bands of a carbonolitc and poor coal in the bauxites.