Ore-forming Material Source Studies Of The Carboniferous Benxi Formation Bauxite Deposit In Western Henan,China

The western Henan is the important bauxite storage bases in China,which has characteristics of large quantity and large scale of deposit and has good prospect of ore-exploration.The ore-bearing rock series of bauxite in western Henan occurred at middle and lower part of the Carboniferous Benxi formation and above the Ordovician carbonate rocks.The ore-bearing rock series of bauxite is controlled by paleo Karst's surface morphology of carbonate,which is composed of bottom iron weathering-crust/clay-rock and upper aluminum-bearing rock series.The bauxite in western Henan is the most typical Karst bauxite in China.Due to its complicated mineralization process and diverse mineral composition,the research on the source of ore-forming material is difficult and needs to be further improved.The geotectonic position of the western Henan belongs to the southern margin of the North China plate,located in the northern Qinling orogenic belt.Due to bauxite was affected by the paleogeographic pattern of south high low-lying north,the ore-forming material are mostly originating from the North Qinling orogenic belt.This paper collected Da'an,Fudian and Gunziying bauxite deposites as the object of study.We used microscope,electron probe(EPMA),X-ray diffraction(XRD)and laser probe(LA-ICP-MS)to investigated the ore texture and structure,mineral composition and the feature of elements of detrital mineral.We focus on detrital rutile origined from bauxite samples of Da'an,Fudian and Gunziying bauxite deposites.By using the method of rutile Nb-Cr discrimination diagram and rutile Zr content thermometer,we can discriminate the lithology of protolith between metamafic and metapelitic and calculate peak temperatures of the last metamorphic cycle.And then,the results of this study can be compared with regional stratigraphics to reveal the source of ore-forming material of western Henan.Meanwhile it explores the new research methods for the study of provenance of karst bauxite in western Henan.Synthesized these research results,comparing with regional stratigraphics of western Henan and the northern Qinling region.we can confine the provenance of in the Carboniferous Benxi formation bauxite deposites in western Henan: the Upper Archean Taihua Group metamorphic rocks in Mianchi-Queshan region and Upper Archean Dengfeng group metamorphic rocks in Songqi region,the Lower Proterozoic Songshan group metamorphic rocks in Songshan;metamorphic rocks of the Lower Proterozoic Qinling group,the Middle Proterozoic Xinyang group,the Mid-Upper Proterozoic Kuanping group,the Upper Proterozoic Taowan group and the Upper Proterozoic Erlangping group in northern Qinling region...