THE ELEMENTAL CONTENT OF NIUE-ISLAND SOILS AS AN INDICATOR OF THEIR ORIGIN

The major and trace element contents of 241 Niue Island lateritic soil s were determined, mainly by X-ray fluorescence, to deduce soil origin s. The analyses showed very low SiO2 content, and a high content of Mg , P, V, Cr, Sr, Y, Hg, and alpha-counts, compared with other laterites worldwide. The distribution patterns are consistent with derivation b y weathering from calcite and dolomite rather than from deposited volc anic ash. Weathering is a particularly novel explanation for the origi n of the relatively high content of P in these soils. The soils contai n a negative Ce anomaly, consistent with an origin from seawater or co ral, but not volcanic ash. If recent results showing in situ formation of magnetite in soils are applicable, the soil mineralogy is wholly c onsistent with an origin from calcite/dolomite. An origin from calcite is also consistent with the relative lack of volcanic ash on the seab ed nearby, and very low deposition of aeolian dust. The radioactivity content is consistent neither with calcite/dolomite weathering, nor vo lcanic ash origin, but may have originated, like a few of the stable e lements, from rising hydrothermal solutions.