The central Karakoram can be divided into three main tectonic units from north to south: a northern Karakoram terrane, the Karakoram batholith, and the Karakoram metamorphic complex. In the Baltoro Glacier region the Karakoram magmatism includes intrusive suites that predate and postdate the India-Eurasia collision. The oldest subduction-related phases include Jurassic hornblendite to biotite monzogranite of the Hushe complex, and Cretaceous (ca. 82 to 75 Ma) hornblende-biotite metagranitoids of the Muztagh Tower unit, all of which were deformed during the India-Kohistan-Karakoram collision. Volumetrically dominant is a postcollisional granite, the Baltoro Plutonic Unit (BPU), which consists of biotite monzogranites to two-mica...