Exhumation history of the Karakoram fault zone mylonites: New constraints from microstructures, fluid inclusions, and 40Ar-39Ar analyses

摘要: The Karakoram fault zone is a dextral strike-slip bounded by the Pangong and Tangtse strands on its NE SW flanks, respectively. In shear zone, microstructures of mylonitic leucogranite exhibit superposition high-temperature deformation followed low-temperature deformation. mylonites show fluid immiscibility, containing brine carbonic inclusions. occurrence carbonic- brine-rich inclusions in oscillatory-zoned plagioclase indicates that they were trapped during formation leucogranite. Eventually, these fluids recorded near-isobaric drop temperature down to 40 Ar- 39 Ar biotite ages indicate area cooled 400–350 °C over 10.34–9.48 Ma, this period also coincides with major phase infiltration trapping secondary reequilibrated saline-aqueous 10.34–9.80 Ma at greenschist conditions, when involved evolved following path ∼2 kbar. Subsequently, between 9.80 9.48 sudden pressure (1.75–0.5 kbar) caused produced inclusion textures. These observations suggest rocks single progressive event bimodal evolution, which available prior initiation zone. 10.34 decrease ∼2–0.5 kbar yields an average uplift rate 1 mm yr −1 for