Marine Terrace - Morphology

Morphology

The platform of a marine terrace usually has a gradient between 1°- 5° depending on the former tidal range with commonly a linear to concave profile. The width is very variable, reaching up to 1000 m, and seems to differ between northern and southern hemisphere. The cliff faces, delimiting the platform, can vary in steepness depending on the relative roles of marine and subaerial processes. At the intersection of the former shore (wave-cut/abrasion-) platform and the rising cliff face it commonly retains a shoreline angle or inner edge (notch) which indicates the location of the shoreline at the time of maximum sea ingression and therefore a paleo sea level. Sub-horizontal platforms usually terminate in a low tide cliff and it is believed that the occurrence of these platforms depends on tidal activity. Marine terraces can extend for several tens of kilometers parallel to the coast.

Older terraces are covered by marine and/or alluvial or colluvial materials while the uppermost terrace levels usually are less well-preserved. While marine terraces in areas of relatively rapid uplift rates (> 1 mm/year) can often be correlated to individual interglacial periods or stages, those in areas of slower uplift rates may have a polycyclic origin with stages of returning sea levels after times of exposure to weathering.

Marine terraces can be covered by a wide variety of soils with complex histories and different ages. In protected areas allochtonous sandy parent materials from tsunami deposits may be found. Common soil types found on marine terraces include planosols and solonetz.