Exhumation of the Fuyun basic granulite in Altaid Orogenic Belt: Constraints from fission-track thermochronology
阿尔泰造山带富蕴基性麻粒岩折返过程: 来自裂变径迹热年代学的限定

On the basis of previous studies of SHRIMP U-Pb chronology, geochemistry, metamorphic temperature/pressure conditions and tectonic setting, fission-track thermochronology has been conducted in this study to determine the exhumation of the basic granulite.Zircon fission-track shows Triassic and apatite fission-track shows Late Cretaceous to Early Cenozoic ages.Thermal history modeling of the fission-track data, combined with previous studies, indicate that the basic granulite was exhumed to the upper crust under about 7.8km in Triassic.From Late Cretaceous to Early Cenozoic (around 100~50 Ma), the basic granulite, meta-diabase and the wall rock gneiss were cooled to the blocking temperature of apatite fission-track, which was about 3.5km below the surface.From approximately 50 to 15 Ma, they stayed at the partly-annealed zone of apatite fission-track, about 1.7km below the surface.Since about 15 Ma to present, they were uplifted and denudated to the surface.