ABSTRACT

Rb-Sr ages of biotite from the southern flank of Mt. Everest, eastern Nepal, range from 14.1 to 1.3m.y., the youngest biotite coexists with muscovite of 7.3m.y. These different ages for different samples reflect the difference in cooling history related to the uplift of the Himalayas. The biotite ages decrease with increasing distance from the high mountain range, suggesting that the high range, i.e., the northern area, was uplifted earlier than the southern area. The relationship between the ages and altitudes of sampling sites indicates that the uplift rate of the northern area was 0.60 mm/yr.