Calcium and Strontium isotopic characterization of surface waters in a small basaltic watershed (Massif Central, France)

Abstract : The chemical weathering of rocks is one of the essential processes in the geochemical cycling of elements because during this process at the earth's surface, rocks and primary minerals are transformed into solutes and secondary minerals, which form soils and sediments. In most countries, human activities also impact the cycle of dissolved species in catchments. We present here a series of calcium isotopes in surface waters draining a basaltic catchment in the Massif Central (France). These data will be interpreted by coupling measurements of 44Ca isotope ratio in waters, rocks, sediments and soils, together with Sr isotopes on the same media. Coupling Ca and Sr isotopes may permit an examination of the relationships of these isotope systematics as Ca and Sr, and K and Rb may behave similarly during weathering of such silicate rocks.