Geochemical characteristics of REY-rich pelagic sediments from the GC02 in central Indian Ocean Basin

Abstract

As a potential mineral resource, the clay minerals enriched in rare earth elements including yttrium (REY) in the deep sea have been attracting great attention. However, the enrichment mechanism of REY remains unclear. To understand the geochemical characteristics and factors controlling REY enrichment in zeolite clay in the deep sea, we conducted mineral identification by XRD, major and trace element measurements by XRF and REY analyses by ICP-MS on a 1.4-m-long sediment core (GC02) located in the Central Indian Oceanic Basin (CIOB). The main findings include: (1) the core sediments in GC02 possess elevated REY contents and exhibited a strong negative Ce anomaly, an apparent MREE bulge and positive Y anomaly. These were comparable with typical REY-rich clays in the Pacific Ocean, indicating the similar REY enrichment mechanism and the presence of REY-rich clays in the CIOB; (2) in comparison with the dataset from the Wharton Basin and DSDP site 213, the higher content of REY and stronger PAAS (Post Archean Australian Shale) normalization patterns in the GC02 sediments were likely caused by the weaker impact of terrigenous materials of GC02. The CIOB was suggested to be a promising place hosting REY rich pelagic sediments.