New U-Pb data from leucogranites in the High Himalayan slab in the western Himalaya of Zanskar reveal that crustal melting occurred at 21–19.5 Ma and that anatexis occurred along the Himalaya at least from Kashmir-Zanskar to eastern Nepal at (Approx.)24–19.5 Ma. High-U monazites from leucogranitic melt pods in migmatites within the 35-km-wide sillimanite + K-feldspar zone at the deepest structural levels exposed (Umasi-la) have U-Pb ages of 20.6–19.5 Ma. Higher-level migmatitic melt pods from Shafat in the Suru valley also contain magmatic monazites with U-Pb ages of 20.8 ± 0.3 Ma. Zircons from the leucogranites contain an (Approx.)460 Ma inherited component, as do some Umasi-la monazites, showing that the protoliths were at least Ordovician in age.

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