Seismic Stratigraphy, Tectonic Structure and Extension Factors Across the Dangerous Grounds: Evidence from Two Regional Multi-Channel Seismic Profiles

Geochemical characteristics of rare earth elements in the surface sediments from the Spratly Islands of China

The geochemistry of rare earth elements (REE) in surface sediment from Cuarteron reef (N1), Johnson reef (N2), Hugh reef (N3), Gaven reef (N4), Fiery cross reef (N5), and Subi reef (N6) were firstly studied. The total REE abundance (∑REE) varied from 2.244μg·g^-1 to 21.661μg·g^-1, with an average of 4.667μg·g^-1. The LREE/HREE was from 2.747 to 9.869, with an average of 3.687, which indicated that the light REE was evidently enriched. Fractionation was observed between LREE and HREE. Gd with a negative anomaly was also detected in all of the stations. The negative anomalies of δEu from 0.11 to 0.25, with an average of 0.22, and the positive anomalies of δCe from 1.38 to 3.86, with an average of 1.63. The REE individual correlation values with Ca, Mn, Mg, Sr were r_Ca=-0.05, r_Mn=0.26, r_Mg=-0.14, and r_Sr=0.08.