| Xixibao manganese ore area lie in the edge of NE Fanjingshan hole which belong to yangtze paraplatform(NNE)’s structural deformation zone. That area losed Carboniferous and Devonian because of arch caused by Caledonian movement. Furthermore, the area was uplifted to be land and then formed folded mountain as a result of Indosinian movement and Yenshan movement. After Himalayan movement, the area was eroded to formed plateau landscape. As a result of tectogenesis’s superimposition and reconstruction in different stages, folds and fractures showed at a NNE on the whole. The stratas in mining area are Fanjingshan Gr(partial emergence), Banxi Gr of Qingbaikou system, Nanhua system, Sinian system, Cambria system, Ordovicia system, Quaternary system. Manganese ore present in underpart of the block shales(manganese-bearing rock series) which lie in Datangpo formations of the Early Nanhua Period.Xixibao manganese ore belong to marine manganese carbonate ore deposits. Three faces such as center face, transition face and edge face formed during metallogenic process. The Mn grade gradually reduced from the center to the edge face while ore bodies gradually pinchouted. This study is based on the element geochemistry datas about manganese-bearing rock series of six bore holes in manganese ore. These bore holes are zkl002, zk1003, zk1004, zk1008, zkl010, zk5005. And zk1010lies in center face, zk5005lies in edge face, then the oher lie in transition face. The deposit thicknesses of zk1002、 zk1003、zk1004、zk1008respectively are4.22m、4.38m、1.39m、3.18m. Besides, there are two layers mine in zk1010, and the deposit thicknesses of them respectively are2.64m、5.42m.1、Trace elements’character of manganese-bearing rock series:Relatively, Mo、As、 Zn、 Ni own a higher distribution, and there exist some abnormal high values about Zn.And Nb、Sr、Rb own a lower distribution. This situation generally exists in different bore holes above. On the whole, all above indicate that minerogenic environment was marine deposit environment.2、Major elements’character of manganese-bearing rock series:Take zk1004for example, S own a higher distribution relatively. And S’values in rhodochrosites are higher than that in carbonaceous shale. Besides, the distribution of Fe, K and Ti in rhodochrosites is lower than that in carbonaceous shale. In vertical, Fe’s practical values are lower compared to continental crust abundance.K’values in rhodochrosites are lower than that in carbonaceous shale even considerably below continental crust abundance. Ca are at a proper distribution, its’values are a small little lower than continental crust abundance on the whole. Pyrites exist pervasively in top and bottom of manganese-bearing rock series and are highly positive in its’ δ34S value which indicate that minerogenic condition was highly isolated and reducing sedimentary condition3、Trace element ratios’character of manganese-bearing rock series:the average values of Co/Ni and Sr/Ba respectively are about0.4and0.3in rhodochrosites. while about0.3and0.2in carbonaceous shale. The lower values of Co/Ni in rhodochrosites indicate that sedimentary water were deep. Sr’ values are higher in rhodochrosite compared to carbonaceous shale, this phenomenon also reflects the deep water sedimentary condition. And the average values of Sr/Ba in rhodochrosites and carbonaceous shale are both less than1, it reflects that Sr stand at a low distribution. These geochemical characteristics what incarnate minerogenic condition show fixed ore-controlling significance and can be regarded as a foundation to forecast mineralize... |
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