Denudation rates in northeast Papua from potassium-argon dating of lavas

Abstract

The Hydrographers andesitic strato-volcano in northeast Papua is in a late planeze-early residual mountain stage of dissection. Potassium-argon dates of fresh massive lavas from near the original surface range in age from 650,000 to 700,000 years. Assuming an age of 650,000 years for the beginning of dissection of the volcano, denudation rates range from 8 centimeters per 1000 years at a relief of 60 meters to 75 centimeters per 1000 years at a relief of 760 meters. These rates are similar to those estimated by conventional methods in west Irian, Indonesia, the Philippines, Guatemala, and northeast Queensland in comparable hot-moist climates and hilly and mountainous terrain.