Sediment-water interface temperature
The surface temperature or sediment-water interface temperature (SWIT) used in models is determined by a combination of:
- Water depth
- Palaeo-latitude using palaeo-continental distribution maps (e.g. Ford and Golonka, 2003; Smith et al., 1981)
The annual mean temperature at the sediment-water interface in aqueous environments is a complex function of mean annual air temperatures and water depth. Water temperatures are a function of the type of marine or lacustrine system, thermal stratification and currents that may transport water from cold high latitudes, where water temperatures are determined by the lowest air temperatures encountered within the range of the specific marine or lacustrine system.
Palaeo-sediment-water interface temperatures are frequently underestimated, as several palaeo-climatological factors are often not taken into account (Frakes, 1979):
- Most continents presently located on the northern hemisphere were closer to the equator in the geologic past.
- During most of Earth history, the temperature distribution was much more even than at present as indicated by the absence of polar ice caps.
- As the coldest bottom water temperatures in open oceanic systems are determined by the coldest water temperatures at the poles, minimum temperatures were mostly higher than at present.
Ford, D., Golonka, J., 2003. Phanerozoic paleogeography, paleoenvironment and lithofacies maps of the circum-Atlantic margins. Marine and Petroleum Geology 20, 249–285.
Frakes, L.A., 1979. Climates Throughout Geologic Time. Elsevier Scientific Publishing Company.
Smith, A.G., Hurley, A.M., Briden, J.C., 1981. Phanerozoic Paleocontinental World Maps, Cambridge Earth Science Series. Cambridge University Press.