Determination Of Intrusive Rock Sequence,geological Significance And Metallogenic Relationship In Kuixiandaban Area,Jejing County,Xinjiang

The study area is located in the Kuixiandaban area of the Central Tianshan Mountains.Large-scale granitic intrusive rocks of different ages have developed in the area.A large number of scholars have conducted geological surveys and mineral surveys on them.However,the granitic intrusive rocks in this area lack accurate dating results and systematic geochemical data.In this paper,combined with systematic field geological surveys,the petrology,geochemistry,and chronology of the intrusive rocks in this area are carried out,with the aim of discussing the emplacement age,petrogenesis types,tectonic background and metallogenic analysis.in order to provide new clues for the closing time of the South Tianshan Ocean and the prospecting work in this area.According to the isotope dating results and Spatiotemporal distribution of the intrusive rock,the intrusive rocks in the Kuixiandaban area of the Central Tianshan are preliminarily divided into three intrusive stages of the Late Silurian,Late Devonian,and Late Carboniferous.Among them,the three rock types of the Late Silurian invasion stage from early to late are: medium-coarse-grained porphyritic monzonitic granite,medium-grained potassium feldspar granite and medium-grained porphyritic potassium feldspar granite;The four rock types from early to late in the Late Devonian intrusion stage are: medium-fine-grained quartz diorite,medium-grained granodiorite,medium-grained monzonitic granite and medium-fine-grained monzonitic granite;The Late Carboniferous intrusive stage consists of four types of rocks: medium-grained quartz diorite,medium-grained monzonitic granite,medium-fine-grained monzonitic granite,and granite porphyry.LA-ICP-MS zircon U-Pb dating determines the age of the Late Silurian potash feldspar granite to be 423±3Ma;The ages of Late Devonian quartz diorite,granodiorite,and monzonitic granite are 365±2Ma,364±2Ma,and 363±2Ma,respectively;The late Carboniferous quartz diorite has an age of 313±3Ma.The geochemical characteristics of intrusive rocks show that the Late Silurian intrusive rocks are a set of peraluminous,high-potassium calc-alkaline series rocks.The genetic type is S-type granite,formed in the late orogenic environment under the combined action of the land-continent collision after the closure of the northern margin of the Central Tianshan Ocean basin and the northward subduction and subduction of the South Tianshan Ocean;The Late Devonian intrusive rocks are a set of high-potassium calcium-alkaline series,para-aluminous-weak peraluminous rocks.The genetic type is I-type granite,which was formed in the subduction and subduction environment of the southern Tianshan Ocean northward;The Late Carboniferous intrusive rocks are a set of high-potassium calcium-alkaline-calcalkaline series and para-aluminous-peraluminous rocks.The genetic type is I-type/differentiated I-type granite,which was formed in the post-collision extensional environment after the closure of the Southern Tianshan Ocean.In summary,combined with previous research results,This paper supports that the Southern Tianshan Ocean subducted under the Central Tianshan block to its north during the Late Silurian-Late Devonian,and closed in the Early Carboniferous,and entered the post-collision extension stage in the Late Carboniferous.Combined with the analysis of typical deposits,this article believes that the late Devonian intrusive rocks in the central part of the study area are closely related to the mineralization of hydrothermal copper deposits;The Late Carboniferous intrusive rocks are closely related to the mineralization of skarn-type lead-zinc polymetallic deposits.