Metallogenic Regularity And Prospecting Prediction Of The Kelan Polymetallic Ore-Concentrated Area,Altay,Xinjiang

Altay of Xinjiang is an important part of the Central Asian Orogenic Belt,which has experienced the evolution of the formation,subduction,collision and closure of Paleo-Asian Ocean,and contains rich mineral resources.The Kelan is an important ore-concentrated area in Altay,with multiple ore deposit types,complex ore-forming element groups and multi-age ore-forming characteristics.Although previous researches have been carried out,the mineralization of some typical deposits remains to be further studied,and the characteristics,spatio-temporal distribution,metallogenic series,tectonic evolution and mineralization of different types of deposits are still unclear.Aiming at the dominant mineral species,the Talate,Wulasigou,Basitielieke and Hongdun deposits are selected as typical deposits in this paper.Through field investigation,microscopic observation,deposit geochemistry,isotope dating and other research methods,the mineralization is discussed.The coupling relationship between tectonic setting,stratigraphic deposition,magmatic intrusion and mineralization in the ore collection area was determined,the metallogenic series of the ore deposit was established,and the regional tectonic evolution and metallogenic model was constructed.Based on the comprehensive information,the metallogenic prediction is carried out.The main achievements are as follows:1.The ore-concentrated area is divided into three sub-ore belts: the North sub-ore belt is pegmatite type deposit,the central sub-ore belt is iron,copper,lead,zinc and gold deposit related to marine volcanism,and the South sub-ore belt is iron,copper,lead,zinc and rare metal deposit related to magmatic hydrothermal activity and exhalative sedimentation.2.The genetic types of the deposits can be divided into exhalative-sedimentary type,marine volcanic type,skarn type,orogenic type and pegmatite type.The exhalative-sedimentary type includes VMS type and SEDEX type deposits.The VMS type polymetallic deposit and marine volcanic type iron deposit are the main types in the Kelan Basin.3.The Talate Pb-Zn-(Fe)deposit and the Wulasigou polymetallic deposit are VMS deposits formed in the Early Devonian.The Talate deposit was superimposed with mineralization related to magmatic hydrothermal alteration in the Permian to Triassic.The Basitielieke tungsten polymetallic deposit is a skarn type deposit,which is closely related to the Permian granitoids.The Hongdun Pb-Zn deposit is a SEDEX type deposit formed in Middle-Late Devonian,and the siliceous rocks in the deposit belong to submarine hydrothermal sedimentation.4.There are four metallogenic periods in the Kelan Basin: Early Devonian(410 ～ 387Ma),mineralization was closely related to marine volcanic activities,deposits formed in continental arc environment.Middle to Late Devonian(382 ～ 354 Ma),mineralization was related to hydrothermal exhalative sedimentation,and was formed in back-arc basin.Early to Middle Permian(296 ～ 258 Ma),mineralization was related to magmatic hydrothermal activity and formed in post-collision extensional environment.Triassic(248 ～ 210 Ma),mineralization was associated with shear deformation and regional thermal events,and tectonic setting was an intraplate environment.5.The deposits in the Kelan Basin can be divided into five metallogenic subseries:(I)the Cu-Pb-Zn-Fe-Mn-P metallogenic subseries related to marine volcanism in Early Devonian;(II)the SEDEX type Pb-Zn metallogenic subseries in Middle to Late Devonian;(III)the Fe-W-Cu-Pb-Zn-Li-Be-Nb-Ta metallogenic subseries related to magmatic hydrothermal activity in Early to Middle Permian;(IV)the metallogenic subseries of pegmatite rare metal deposits in Early to Middle Triassic,and(V)the metallogenic subseries of Au deposits related to shear deformation in Late Triassic.6.Based on the study of the geological background,characteristics of mineralization,genetic type of ore deposit,spatio-temporal distribution and metallogenic series of Kelan polymetallic ore-concentrated area,combined with regional remote sensing information and geophysical-geochemical anomaly information,the prospecting marks of five types of ore deposit were established,and seven prospecting targets were rounded out in the ore-concentrated area.In the aspect of ore prospecting,the deep,margin and periphery of existing deposit are still the key exploration areas.