Modelling coastal notch morphology and developmental history in the Mediterranean

Abstract

Coastal notches are used as paleo-sea level markers and to determine rates of tectonic uplift. This has been especially important in warm, microtidal seas. Modelling was used in this paper to test the hypothesis, developed in the Mediterranean, that the shape of notch profiles provides insights into changes in relative sea level (RSL) and modes of tectonic activity. Variables in the model included local factors such as the gradient of the initial slope, whether notches collapsed or remained stable, and rock strike, dip, and bed resistance to erosion. The main regional-scale variables included climatically induced changes in erosional efficacy and a variety of uniform and episodic, positive and negative changes in RSL. Model results suggest that attempts to use notch profiles to identify changes in climate and RSL must be accompanied by careful field observation and mineralogical analysis in order to extract the obfuscating effects of local factors. Similar notch profiles can be produced by different combinations of local and regional factors and, based on ambiguous field evidence, differentiating the morphological effect of changes in RSL from the effect of these other factors may continue to be problematic, especially where there has been low tectonic activity or stability.