Petrogenesis of monzonites and leucogranites in the Ama Drime Massif: Implications for sources and differentiation of Himalayan leucogranites

•The 13.5 Ma monzonites and the 10 Ma two-mica and tourmaline leucogranites were identified in the Ama Drime Massif.•The source of the magmatic rocks in the Ama Drime Massif was entirely composed of Paleoproterozoic orthogneisses.•The Himalayan leucogranites underwent magmatic differentiation, with the formation of complementary cumulate rocks.•The Himalayan leucogranites can not be simply classified into S-type granites.