2000 Volume 95 Issue 7 Pages 173-181
The post-collisional Garam Chashma leucogranite with K-Ar (biotite) ages of 20-18 Ma occurs in the Hindukush Range (Trans-Himalayas), northwestern Pakistan. The leucograntie is per-aluminous and shows a restricted range of SiO2 contents (72-75 wt%). It is different, both in mineralogy and chemical characteristics, from the surrounding pre-collisional granodiorites and post-collisional meta-aluminous to per-aluminous Miocene Baltoro granite from Trans-Himalayas in Northeast Pakistan. The age and chemical trends of Garam Chashma leucogranite are similar to those of the Higher Himalayan granites of Pakistan, India, Nepal and South Tibet, suggesting similar source and/or processes of formation.