Zircon and cassiterite U-Pb age constraining Eocene mineralization of the Mawchi Sn-W deposit,Kayah State,Eastern MyanmarOA

1.Objective The Southeast Asian W-Sn belt,stretching over 2800 km from Yunnan Province in China through Myanmar,Thailand,Peninsular Malaysia,and into Indonesia(Figs.1a,b),is recognized as the world’s most significant tin resource base.The W-Sn mineralization in this region is closely associated with Mesozoic-Cenozoic granites.Within this belt,Myanmar,as a central segment,hosts approximately 400 Sn-W deposits,prospects,and occurrences,making it a major global tin producer.It contributes 6.2%of the world’s tin reserves and 18.6%of its tin production.Among these deposits,the Mawchi Sn-W deposit in Myanmar stands out as a world-class deposit,with estimated ore reserves of 31×10^(6)t.This deposit has been a focal point for geological studies,with extensive research conducted on its geology,geochemistry,zircon geochronology of the ore-related granites,and molybdenite Re-Os geochronology.In recent years,there has been a notable scarcity of new data on the mineralization age of the Mawchi deposit,particularly the absence of in situ cassiterite U-Pb ages,which are crucial for directly determining the mineralization age of Sn deposits.In this study,the authors present the U-Pb dating results of both zircon and cassiterite from the Mawchi Sn-W deposit(N18°49.322'',E97°49.322'',1044 m),providing critical constraints on the mineralization age and offering valuable insights into the genetic relationship between Tethyan tectonic evolution and tin mineralization.