Natural Resources Management and Environmental Sciences Department
BS in Earth Sciences
Antonio F. García
Marine terrace formation is in many instances attributed to wave action, and shore platforms are often called “wave-cut”. However, alternative models for marine terrace formation suggest that other types of physical and chemical weathering have a more central role in the formation of marine terraces than is widely acknowledged. Roering and Retallack (2012) concluded that the roles of subaerial physical and chemical weathering are significant, and played a major role in the formation of the terraces. In this study, weathering of beach cliffs and shore platforms associated with marine terraces at eight sites in two different locations along the central California Coast is assessed, and results are compared to those of Roering and Retallack.
Findings for rock hardness along the profile of modern shore platform and cliff face are similar to the results from the Roering and Retallack study: the Schmidt rock hardness of cliff faces within the bottom 1.5 meters above the modern shoreline angle are significantly lower than the rock hardness of the shore platform. Oxidation color of shore platforms, assessed using a Munsell color and described in Munsell color notation, is consistently within the Gley 1 range in both study areas. Beach cliff oxidation color varied from Gley to colors indicating oxidation. Oxidation on beach cliffs was more prevalent within the upper half meter of the part of the beach cliff that was sampled, and oxidation within fractures and cracks was also apparent in some cliff faces.