Rare earth, major, and trace element composition of Leg 127 sediments

Abstract

Examines 59 squeeze-cake whole-round and 27 physical-property sample residues from Sites 794, 795, and 797, cored during ODP Leg 127. The most important variation in sedimentary chemical composition is the increase in SiO2 concentration through the Pliocene diatomaceous sequences, which dilutes most other major and trace element components by various degrees. REE total abundances in the Japan Sea are strongly dependent upon the paleoceanographic position of a given site with respect to terrigenous and biogenic sources. REE concentrations at Site 794 overall correspond well to aluminosilicate chemical indices and are strongly diluted by SiO2 within the Upper Miocene-Pliocene diatomaceous sequence. Ce/Ce* profiles at all three sites increase essentially monotonically with depth and record progressive diagenetic LREE fractionation. The REE chemistry of Japan Sea sediment predicts successive downhole addition to LREEs to deeply buried interstitial waters. -from Authors