Thermal diagenesis in the Swiss molasse basin: implications for oil generation

Abstract

Clay mineral transformations during burial are indicators of the degree of diagenesis of sediments. Diagenetic zonations in numerous wells of the Swiss molasse basin are defined by the disappearance of smectite and (or) the appearance of either corrensite or irregular 2:1 mixed layers. The maximum level attained in the thickest molasse sections corresponds to organic matter maturation suitable for hydrocarbon generation. Reconstructed on the basis of the clay mineral transformation data, a burial history of the basin is proposed.