Trace elemental and Sr-Nd isotopic geochemistry of foraminifera shell of the Okinawa Trough

Trace elemental associations and Sr,Nd isotopic compositions are of important for recognition of biogenic material from mixed marine sediments.The foraminifera shell of the Okinawa Trough strongly enriches Sr,PMn and Ba,enriches Li,U,Th,Sc,Co,Cu,Pb,Y,Zn,Cr,Rb,Sb and light rare earth elements,slightly enriches V,Ga,Zr,Nb,Cd and middle rare earth elements,and is relative short of Mo,In,Sn,Cs,Hf,Ta,W,Tl,Bi and heavy rare earth elements.The mechanism of element enrichment of foraminifera is the concentrations of trace elements in sea water and selective absorption of trace elements during foraminifera living,as well as the geochemical affinity between major elements and trace elements.The REE partitioning pattern of foraminifera shell of the Okinawa Trough shows enrichment of middler are earth elements and slightly negative Ce anomaly,which are different from those of foraminifera of the Pacific Ocean.The Sr,Ndisotopic ratios of the Okinawa Trough foraminifera are 0.709769 and 0.512162,respectively,which are different not only from those of oceanic water,but also from those of river water of China.Mainland,the former is slightly higher than that of oceanic water,but much lower than that of river water,the latter is slightly lower than that of oceanic water,but higher than that of river water,which demonstrates that the Okinawa Though sea water has been influenced by river water of China.Mainland.