Changes in Pb isotopic compositions over the past 800,000 years in EPICA Dome C Ice Core from Antarctica

초록

Records of the Pb isotopic compositions are presented for the EPICA Dome C ice core covering the past 800 kyr. Changes in Pb isotopic compositions provide a time-integrated record of fingerprinting regional and global patterns of atmospheric dust transport. The EPICA Dome C ice core samples were mechanically decontaminated by ultra-clean procedures in a cold room and all sample treatments were conducted under either class 10 clean bench or class 100 clean hood. Pb isotopes were measured using thermal ionization mass spectrometry (TRITON, Thermo Scientific). Previous studies of Pb, Sr and Nd isotopes in Antarctic deep ice cores suggested that Southern South America (SSA) was an important source of dust in Antarctic ice during both glacial and interglacial periods. These studies also showed that Australia was not a major component of Antarctic dust whatever the period. Here we present the first Pb isotopic evidence that dust from Eastern Australia could be an important source of Antarctic dust between 300 kyr BP and 600 kry BP.