Dating techniques in geomorphology
Structural notches can be found in rock formations characterized by gently dipping beds where differential erosion can be active along weaker strata, forming notched profiles.
These notches can be easily recognized in the field because their longitudinal profile follows the original line of weakness.
Marine terraces can be shaped by marine erosion (wave-cut terraces) or can consist of shallow water to slightly emerged accumulations of materials removed by shore erosion (i.e., marine-built terraces).
This latter type is usually characterized by the presence of deposits of marine origin, which can include marine fauna.
Given the discontinuous nature of shallow water/land sections, oxygen isotope stratigraphy is only likely to be of use in deep ocean sediment cores.
Sr in ocean water has varied continually through time reflecting changes in the balance between the processes that supply and remove strontium to/from the oceans.
Caves in limestone coasts can contain tidal notches or fossil bands of bioerosional organisms that provide morphological evidence of former sea levels, while caves cut in other types of rocks may contain landforms such as abrasion notches and platforms that, associated with deposits, may also indicate the position of a former sea level.Shore platforms can be characterized by a number of lower-scale features, which are due to the presence of particular rock structures or environmental conditions (e.g., different lithological properties along the platform or strong wave action). The debate on the processes shaping shore platforms results in uncertainty regarding the elevation of platforms with respect to sea level.Indeed some are shaped above mean sea level while others are intertidal. Researchers have divided marine notches into tidal notches, surf notches, infralittoral notches, abrasion notches, structural notches.Reef flats are a particular type of marine terrace developed in inter-tropical environments as a result of bioconstruction as opposed to marine erosion processes that are selected according to the type of material available for dating as well as stratigraphic considerations.Because they are relatively easily dated, marine terraces are often used as geomorphic sea level markers When the inner margin of the terrace is clearly identifiable (e.g.