Sedimentation Feature Of Manganese-bearing Rock Series From The Upper Devonian, Southwest Of Guangxi, China

The manganese ore deposits in Guangxi is the most then other province in China, and manganese-bearing rock have many series, manganese ore have a lot of types.In Guangxi,70%deposits of manganese ore are in Southwest of Guangxi.So the most importantly production of manganese ore in China is the Southwest of Guangxi.In this area manganese ore are mostly concentrate in Jingxi County、 Tiandeng County、Debao County、Daxing County. According to the genesis of ore types are divided into two types of sedimentary deposits and deposits of weathering. There are a lot of strata containing manganese, From the Proterozoic to Cretaceous,14layers containing manganese, One of the most important is upper Devonion series.In southwest of Guangxi manganese-bearing rock series from the Upper Devonian are Liujiang Formation and Wuzhishan Formation, The LiuJiang Formation have gray-black chert, siliceous limestone interbedded with manganese ore; The Wuzhishan Formation is a set of mudstone, siliceous mudstone, lenticular limestone, clip the manganese-bearing limestone, argillaceous rocks containing2-3layer of manganese carbonate ore. Liujiang Formation containing manganese ore are mainly located in Tuhu,and Wuzhishan Formation as the most important manganese-bearing strata, Xialei, Xinxing, Bahe, Longbang, are produced in it.In this paper, based on our detailed interior of Upper Devonian manganese formation of field investigation and the measured profile in southwestern Guangxi, Combined with previous data, to study the sedimentary characteristics of manganese rock containing this region.Major work,knowledge and results summarized as follows:1. We collect, analysis the information about the study area containing manganese formation in southwestern Guangxi, found that the study area of the upper Devonian manganese rocks are exposed less. Most of the region in which the late Devonian is the syndepositional relationship Rongxian formation. The manganese-bearing rock series of Liujiang Formation and Wuzhishan Formation mainly concentrated in the south of the area, with limited distribution range. Therefore, we determined the concrete implementation method of the field work, is aimed at different facies belt layout related geological section, in order to understand the different facies sedimentary environment2. Through field observations, study and comparison of the previous data. Recognizing the containing manganese rocks is controlled by sedimentary facies control law of the obvious in the study area.we find manganese occur in siliceous rocks and siliceous limestone rocks, Manganese was not found in the micritic limestone and dolomite. Through the study of sedimentary facies and sedimentary facies of the transverse,we find that whether LiuJiang formation or Wuzhishan Formation deposition of the manganese-bearing rock series are in the channel environment which of water were weaker power. So we conclusion that the study area containing manganese rocks has a close relationship with the channel phase. Using natural gamma data in the field of measured mine, The sedimentary environment of the manganese-bearing rock series in the reduction of interface for oxidation, Sedimentary water was about100m,.Based on the above conclusions, we propose the depositional model in study area.3. The study area can be divided into three sedimentary facies zone during the late Devonian,there are restricted platform, syneclise facies and slope facies. The restricted platform can be divided into oolitic shoal,lagoon facies beach and platform concave. The main rocks are microcrystalline limestone, Oolitic Limestone, dolomite. Syneclise facies distribution in the south of the study area, Rock are siliceous rocks and siliceous limestone; Slope facies rocks are calcirudite, lenticular limestone,it can be subdivided into upper slope and lower slope facies.4. The study area manganese-bearing strata have obvious zonation and limitations, In the process of compilation of lithofacies palaeogeography maps,useing plane method and the distribution of sedimentary facies, The method of image formation analysis play an important role in the process of drawing the lithofacies palaeogeography maps.From the paleogeographic map,finding that the area of Xialei,Hurun,Longbang have the barrier effect of natural to cause the water flow. And because the tensile action area in the southwest of Guangxi leads to deposition of manganese to regression between Famennian, upper Devonian. Therefore, in the study area is easy to form large manganese deposit.5. Trace elements analysis of manganese ore and siliceous rocks. Using the SPSS software to analysis the data which are measurement data and non manganese-bearing rock series of geochemical data. From Q cluster, Manganese ores exhibit a high degree of similarity and siliceous rocks in the trace element. The clustering results of R display that the Mn element and terrigenous elements of Ga in manganese ore has good linear relationship. Through the silicon and oxygen and carbon stable isotope analysis, Find manganese deposits in the study area is terrigenous sedimentary mineral deposit, and hot water makes manganese ore more enriched after Manganese has been formed.