Ultrapotassic Post-Collisional Dyke from the Ladakh Batholith, Northwest Himalaya

We report here petrographic and bulk geochemical characters of an ultrapotassic dyke from the Ladakh batholith, NW Himalaya, for the first time, and attempt to compare it with similar dykes from SW Tibet which are typical of post-collisional magmatism. Postcollisional shoshonitic and ultrapotassic dykes have been reported from north Karakoram (Pognante, 1990) and potassic and ultrapotassic lavas from SW Tibet by Miller et al. (1999). They have been linked to large scale tectonic reactivation involving the lithospheric mantle during the continued India-Eurasia collision since ∼50 Ma.