Geochemical Characteristics And Discussion Of Attribution To The Neoproterozoic Metamorphic Rocks,Aierbin Area In West Tianshan Mountains

Aierbin mountain is located in the South Tianshan orogenic,and is mainly composed of the Aierbin pre-arc accretionary complex belt.It is bounded by the southern of Central Tianshan fault?Changawuzi-Wuwamen-Kumishi fault?,the northern part belongs to the Central Tianshan block and the south is part of the South Tianshan orogenic.South Tianshan orogenic belt is mainly composed of Paleozoic geological bodies,Only a small amount of the Precambrian crystalline base was exposed in the Muzaerte river area.The metamorphic rocks studied in this paper are a set of Precambrian crystalline bases newly determined in the pre-arc accretionary complex belt of the Aierbin mountain in the South Tianshan mountains.It is an indispensable part of the study of the Precambrian crustal growth in the Central Asian Orogenic Belt through the study of the metamorphic basement to discuss the evolution process of Tianshan ancient landmass.The range of metamorphic rocks was exposed in this study area is relatively concentrated,exposed in the northern margin of Aierbin mountain,with layered and lenticular shapes,strong deformation,generally degraded,and accessible to amphibolite facies.The rock formations are dominated by quartz schist,hornblende schist,super-granulite,granite gneiss,and oblique hornblende gneiss.They were invaded by Neoproterozoic acid-bearing rocks in the later period.Aierbin mountain metamorphic rock has the characteristics of rich Al,REE elements showing the LREE enrichment and HREE flat.According to the recovery of major element elemental rocks,the metamorphic rocks on the Aierbin Mountain are pararock,With the results of the analysis of trace and REE,the pararock material source is quartz and felsic rocks,is a form in continental island arc have base-acidic volcano-miscellaneous sandstone formation,with khondalites characteristics.The metamorphic clastic rock have experienced warm and moist weathering environment,have low maturity.Bi-Pl gneiss zircons are magmatic zircons,the youngest zircon age is 910±10Ma,which represents the upper age limit of the pararock rocks,it is believed that the strata was formed after the early Neoproterozoic.The zircon ages have three less obvious age peaks:910–1113 Ma,1916–2074 Ma,and 2630–2698 Ma,corresponding to the age of Archean continental nucleus Pangaea proliferation,and the time of the final assembly and dispersal of Columbia and Rodinia supercontinent.The Paleozoic crustal growth has good comparability with the ancient land block in the Central Tianshan mountains and the ancient land block in the Kuruktag region.By comparing the metamorphic rocks in the study area with the Narat group in the Central Tianshan mountains and the Muzaerte group in the South Tianshan mountains,it is believed that the Aierbin mountain metamorphic rocks are equivalent to the Neoproterozoic Nalati group?Pt₃N.?in the Central Tianshan mountains,the southern of Central Tianshan fault need southward,which wes through the northern of Aierbin.