CHEMICAL LEACHING OF PELAGIC SEDIMENTS - IDENTIFICATION OF THE CARRIER OF CE ANOMALY

Several chemical leaching experiments were carried out to characterize the REE distribution in four pelagic sediments which have negative Ce anomaly collected in Central Pacific. Extraction experiments indicate that the carrier of the negative Ce anomaly is phosphate phase. This result supports our hypothesis that a negative Ce anomaly is mainly due to fish bone debris in the Pacific equatorial pelagic sediments, in case of pelagic sediments far from the areas of hydrothermal activity. Furthermore, a positive Ce anomaly in pelagic sediments was confirmed by leaching experiment to be due to hydrogenous components (Mn-Fe oxides). The terrigenous component (silicate phase) has a low REE content and a flat shale-normalized REE pattern.