Quantitative modelling of basin subsidence caused by temperature-driven silica dissolution and reprecipitation

Equations describing the rate of vertical thinning of sandstones due to pre cipitation of quartz cement produced at stylolites are derived for constant temperature and for a linear temperature change. Ail temperature histories can be approximated by a series of linear segments, and the equations ther efore enable the diagenetic thinning of sandstones undergoing quartz cement ation to be calculated as a function of temperature history. Application of the equations to interbedded sandstone-shale sequences indicate that for h eating rates and geothermal gradients commonly encountered in sedimentary b asins, thermally driven diagenesis leads to cumulative rates of sandstone t hinning in the range of 1-10 m Ma(-1). This implies that when effects of th ermally driven shale diagenesis, mechanical compaction and isostatic adjust ment are taken into account, thermochemical diagenetic thinning may explain a large proportion of the total generation of accommodation space in many basins. The equations describing the rate of sandstone volume reduction and , therefore, rate of fluid expulsion, could also be utilized for calculatin g overpressure development.