Computer simulation of the influence of basin physiography on condensed section deposition and maximum flooding

Abstract

Sequence stratigraphic analysis commonly involves the correlation of condensed sections, which are widely used as chronostratigraphic markers. Condensed sections represent periods of very slow deposition due to sediment starvation and have generally been equated with the maximum flooding surface, which is most commonly inferred to occur at sometime between the maximum rate of relative base level rise and the highest point of relative base level. However, similar sediment starvation can be produced by a rapid landward shift in the shoreline over large distances during the early stages of a base level rise over a very low-gradient surface. Condensed section deposition therefore does not always correspond to a period between the maximum rate of relative base level rise and the highest point of relative base level, but can be initiated earlier than the maximum rate of relative base level rise or conclude after the highest point of relative base level. The initial timing and the duration of condensed section deposition is therefore influenced by basin physiography. Basin physiography can also contribute to a diachronous maximum flooding horizon lying at different levels throughout a basin, because the rate of change in accommodation during fluctuating base level is partially dependent on the slope of the basin surface. These principles are illustrated in the paper by computer simulations.