Early Permian Au-Ni major metallogenic events in western Central Asian metallogenic domain
The Late Paleozoic is an important period in Earth's history,containing key information about the superconti-nent Pangaea,the Great Ice Age,the most severe mass extinction,and the formation of vast mineral resources.The Central Asian Metallogenic Domain,located in the heartland of the Eurasian continent,is the largest Phanero-zoic continental accretion zone. It is characterized by extensive mineralization event in the Late Paleozoic,partic-ularly during the Early Permian (270～290 Ma),when significant gold and nickel mineralization occurred in Tian-shan and adjacent areas,western part of Central Asia. This event resulted in the formation of over 11,000 tons of gold,which created the world's second-largest gold mineralization province. Meanwhile,2.5 million tons of nick-el was formed in the eastern Tianshan,Irtysh,and Beishan clusters,which contain eight large to super-large-sized deposits. This represents a globally rare coeval gold-nickel mineralization event. Based on the latest researches,this article provides a preliminary and systematic discussion of the temporal-spatial distribution and fundamental characteristics of the large-scale gold and nickel mineralization in the western part of the Central Asian Metallo-genic Domain during the Early Permian. The dynamic background and mineralization mechanisms of this major mineralization event were also investigated. The study suggests that the Early Permian gold deposits are associat-ed with brittle/ductile deformation zones near the Tianshan suture zone,forming a unique continental deformation belt gold mineralization system,which cannot be fully explained by the existing metallogenic theories. The key factors for large-scale gold mineralization may include thick carbonaceous clastic rock sequences,regional meta-morphism induced by block uplift,multiple sources of fluids,multi-stage tectonic activation and gold enrichment,and the coupling and superposition of multiple factors. The Early Permian nickel deposits hosted by mafic-ultra-mafic intrusions are linearly distributed along the major faults in the Tianshan-North Altai region. This region ex-hibits the strongest nickel mineralization among global orogenic belts and provides the most discovered deposits.Key factors for significant magmatic nickel mineralization in orogenic belts include high-degree partial melting of the subducted melt/fluid-modified lithospheric mantle/asthenosphere,regional deep faulting providing path-ways for basaltic magma migration,sulfide segregation caused by the addition of crustal materials,and reactions between the sulfides and multiple episodes of magma. Overall,the major gold-nickel mineralization event during the Early Permian in the western part of the Central Asian Metallogenic Domain exhibits a "temporal-spatial cou-pling,with gold in the west and nickel in the east" pattern. However,there are still many mysteries regarding the regional and global dynamic background of significant mineralization,the mechanisms of gold and nickel enrich-ment,and the mechanisms of mineralization.
Early Permiancontinental deformed zone hosted gold mineralization systemmagmatic nickel mineralization system in orogenic beltsmajor metallogenic eventCentral Asian Orogenic Belt
国家科技期刊平台
NSTL
万方数据
