Climate-induced denudational changes during the Little Ice Age inferred from 10Be (meteoric)/9Be ratio: A case study from the core monsoon zone of India

Abstract

Denudation rates are often estimated with high uncertainty using the average mass of material discharged through a drainage basin or considering the rate of surface processes. Estimating long-term denudation rates through these conventional methods requires the assumption that the surficial processes have remained constant throughout time. Since the earth's surface has been obliterated throughout the geological time by climate, tectonics, or the recent anthropogenic activities, the present rate of change may not represent past processes. This study presents changes in denudation rate using the 10Be (meteoric)/9Be ratio for the past 600 years from Anshupa Lake sediment record in the core monsoon zone of India. Paleodenudation rate estimated using 10Be (meteoric)/9Be varies from 392 ± 42 to 95 ± 6 t/km2/yr. Intense Indian Summer Monsoon (ISM) during the periods of solar maxima, which caused decadal-scale floods in the Indian sub-continent, favored a higher rate of denudation than the periods of solar minima, that experienced droughts in the Indian sub-continent due to weakening of ISM.