Abstract:  The petrogenetic age and magmatic evolution of large granitic complexes are significant for elucidating petrogenesis and deep-seated dynamic processes. The Huangyangshan pluton in eastern Junggar, Xinjiang Province, a typical granitic complex within the Kalamaili alkali-rich intrusion belt, is featured by accompanying alkaline and aluminous A-type granites and hosting two large crystalline graphite deposit closely associated in its aluminous unit. However, the petrogenetic sequence of its lithofacies and the relationship between magmatic evolution and graphite mineralization remain debated. Based on detailed field geological investigations and previous data, this study conducted SIMS zircon U-Pb dating analyses on different lithofacies of the Huangyangshan pluton, and discussed its evolution sequence, the relationship between magmatic evolution and graphite deposit formation. The results reveal reveal a clear south-to-north progression: Fine-grained biotite alkali-feldspar granite ((312.7±1.4)Ma), medium-coarse-grained biotite alkali-feldspar granite ((313.5±1.5) Ma), medium-fine-grained amphibole alkali-feldspar granite ((302.4±1.9)Ma), medium-grained arfvedsonite granite ((297.7±1.5)Ma), and medium-fine-grained arfvedsonite granite ((297.1±1.5)Ma), all formed in the Late Carboniferous, showing a clear magmatic evolution sequence from early to late stages. The ~15 Ma duration of aluminous A-type magmatism likely controlled the super-large graphite deposit formation within the pluton. The formation of the Huangyangshan pluton initially involved dehydration melting of biotite and amphibole in calc-alkaline rocks in the magma source area to generate the aluminous A-type unit. Subsequent partial melting of hornblende (+ minor biotite) in the pre-existing calc-alkaline rocks, induced by mantle-derived high-temperature magma or alkali-rich fluid metasomatism, ultimately formed the alkaline A-type unit in the northern part of the pluton.

Key words: Huangyangshan granitic complex, A-type granite, SIMS zircon U-Pb dating, multi-period magmatic process, crystalline graphite deposit, eastern Junggar orogenic belt