| Metal tin polymetallic deposit in Guangxi as a remarkable ore deposits,which has typical significance in the study,at both home and abroad.Giant assignment of devonian system formation is the major seam mining area,previous research mainly focus on mining and rock mass structure.However lithofacies paleogeographic study is less.The mining area with the most depleted of the growing crisis of mines,large factories and mines fields is also not exceptional.To provide basic geological data for mining the deep prospecting and also to provide a basis for the study of the genesis,based on the "giant mining area of Guangxi devonian lithofacies paleogeographic and control of the metallogenic role" project as the backing,combining previous research status quo of the mining area and analyzing the regional sedimentary background.This paper mainly focuses on the microscopic observation of the rock,the main elements,trace elements and rare earth elements,stable isotopes of test and analysis,through the elements of the microscopic observation and test result analysis,discusses the different sedimentary environment formed by the geochemical characteristics of rocks,and sedimentary structure characteristics of the comprehensive utilization of sediment in macro.It is concluded that when sedimentary paleoenvironment,paleogeographic characteristics summarizing the research results are as follows:(1)Through thin section microscopic observation,analysis of mineral composition and characteristics of the content of residual particles and matrix and cement cementing discussed in this paper,paleontological types and combined with the feature of external macro.It is concluded that mining area the sedimentary microfacies types:bioclastic-cutting micro breccia microfacies;bioclastic grainstone-mud grainstone including complete fossil granular mud limestone microfacies;bioclastic grains marl microfacies;cladding and particle grey mudstone microfacies;cladding,abrasion,bioclastic grainstone microfacies.(2)In the former research on the regional lithofacies paleogeographic basis,according to the best of my test of rock major elements,trace elements and rare earth elements,stable isotope geochemical data,and the curves in different strata,and combining with the depositional characters of every period,on the basis of full analysis.It is concluded that mining devonian period the lithofacies paleogeographic type,specific type:early early devonian to the early transgressive clastic tidal flat facies clastic rock shore coast-nearshore facies,middle early devonian in subtidal zone-limited clastic shelf facies basin,late early devonian carbonate basin.Middle devonian to early carbonate shallow basin and the late devonian in biological reef facies,inheritance and continuation of the sedimentary facies in the early development of carbonate basin facies.Late devonian to early stage groove-basin facies,in the late devonian,late for shallow basin facies. |
