MINERALOGY AND GEOCHEMISTRY OF THE MESOZOIC SEDIMENTS OF ANDOYA, NORTHERN NORWAY

Five samples of weathered basement and forty-four samples of shales and siltstones from the Mesozoic sequence of Andøya, have been analysed mineralogically and geochemically. Mineralogical studies have been performed by X-ray diffraction analysis. Si, Ti, Al, Fe, Mn, Mg, Ca, K, P, Cr, V, Rb, Sr, Zn, Ni, Ba, Zr and S have been determined by X-ray fluorescence (XRF), while Na, Th, Sc, Cs, Co have been determined by instrumental neutron activation analysis (INAA). Organic carbon was determined by a gravimetric combustion method. The Mesozoic sediments on Andøya are mainly made up of weathering products from the Fiskenes granite, but with an increasing influx of more gabbroic weathering products in the youngest beds. The mineralogical and geochemical variations in the sediments mainly reflect variations in source rock composition. © 1979.