Noble gas abundances in a deep-sea sediment core from eastern equatorial Pacific

Abstract

The dried sediments from a single deep-sea sediment core taken in the eastern equatorial Pacific showed progressive enrichment in heavy noble gases 132Xe). Mean-while, light noble gases (4He, 20Ne), especially 2QNe, were severely depleted. The noble gas abundances classified into type 1, observed in Terrestrial sedimentary rocks and natural gases, can be formed as a mixture of the observed noble gas abundances with those in water. The concentrations of &4Kr and 132Xe show no systematic variation with depth, and correlated directly with the Si02 content and inversely with the CaC03content. Leaching experiments to remove CaC03confirmed that siliceous fossils were better adsorbers of heavy noble gases than calcareous fossils. Very high 3 He/4 He ratios of 0.7 X 10–4and 1.3 X were observed in these leached samples. © 1986, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.