Estimating palaeo-water depth from the physical rock record

Palaeo-water depth and its change with time is a key factor in environmental analysis and in sedimentology in general. The literature published on this topic and on related subjects, however, is substantial albeit scattered within and between different communities (geologists, oceanographers, engineers, physicists etc.). Here I focus on proxies for palaeo-bathymetry as obtained from the physical rock record. Floral, faunal and chemical evidence for palaeo-water depth, being equally important, must be dealt with elsewhere. An assessment of the main depth-related parameters in actualistic settings is presented and their applicability to the fossil sedimentary record discussed. The outcome reveals the full complexity of this topic. There is, for example, no such thing as an average wave-base depth applicable to a wide range of fossil case settings. This because wave and current climates in general, and particularly so in neritic and coastal settings, are intriguingly complex. Furthermore, observations from modern oceans are not a priori applicable to fossil ones. Acknowledging these problems and limitations, critically evaluated quantitative proposals for depth indicative facies and features in the sedimentary record are presented and error bars discussed.