Major and trace element abundances in <180 and 180-2000μm fractions of stream sediments from the Hii River, Shimane Prefecture, Japan

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Stream sediments collected from 47 localities in the Hii River of Shimane Prefecture were hand sieved to separate the ＜ 180μm and 180-2000μm fractions．Major and trace compositions of both fractions in each sample were determined by X-ray fluorescence analysis．Elemental abundances contrast significantly between the two size fractions．Average abundances of SiO_2，K_2O，Ba，and Rb are greater in the 180-2000μm fractions，whereas the remaining elements are generally more abundant in the ＜180μm fractions．Loss on ignition values are also greater in the ＜180μm fractions．
Average compositions of both fractions show similar normalized distributions to average upper continental crust．The greatest departure from upper continental crust composition is observed in the ＜180μm fraction，with enrichment for several ferromagnesian elements（V，TiO_2，Fe_2O_3t，Sc）and for Zr，Y，and Th．In both fractions，Nb，CaO，Na_2O，Sr，Rb，MgO and Ni are slightly depleted relative to UCC．