A quantitative definition of accommodation: Implications for understanding and prediction of strata

Accommodation, the space available for potential sediment deposition, is a central concept for stratigraphic heterogeneity prediction and deciphering Earth history. We define accommodation quantitatively as mean thickness of potential deposition per unit of time, calculated per unit area based on a maximum deposition rate and slope-controlled probabilities of erosion and deposition. Testing this definition in a simple numerical stratigraphic forward model reproduces key stratal geometries and behaviors, suggesting basic predictive power. However, the model output is missing much stratigraphic detail, and it is difficult to see how this can be added through extension of the accommodation definition. This suggests that accommodation has less predictive power than typically assumed; many important elements of stratal prediction must come instead from independent calculation of sediment erosion, routing, and depositional processes.