Isotopic signatures for natural versus anthropogenic Pb in high-altitude Mt. Everest ice cores during the past 800 years

Abstract

A long-term record, extending back 800 years (1205 to 2002 AD), of the Pb isotopic composition (206Pb/207Pb and 208Pb/207Pb) as well as Pb concentrations from high altitude Mt. Everest ice cores has the potential to identify sources and source regions affecting natural and anthropogenic Pb deposition in central Asia. The results show that the regional natural background Pb isotope signature (~1.20 for 206Pb/207Pb and ~2.50 for 208Pb/207Pb) in the central Himalayas was dominated by mineral dust over the last ~750 years from 1205 to 1960s,mostly originating from local sources with occasional contributions of long-range transported dust probably from Sahara desert and northwestern India. source regions affecting natural and anthropogenic Pb deposition in central Asia. The results show that the regional natural background Pb isotope signature (~1.20 for 206Pb/207Pb and ~2.50 for 208Pb/207Pb) in the central Himalayas was dominated by mineral dust over the last ~750 years from 1205 to 1960s,mostly originating from local sources with occasional contributions of long-range transported dust probably from Sahara desert and northwestern India.