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The great variety of climatic conditions, tidal ranges and wave regimes of South and Central America act on a complex geology and tectonic framework. Many of the rock and cliffed coasts of South America are strongly controlled by the occurrence of extensive Cenozoic and Pleistocene sediments that crop out at the coast. Geology and the different uplift rates are a major factor in the whole coastal geomorphology of South and Central America, and consequently are a very important control of the processes and landforms of rock coasts. This chapter covers several aspects of the rock coast of South and Central America, with special attention to the combination of tectonic movements and Quaternary Pleistocene-Holocene sea-level changes.

A combination of sedimentological, geomorphological, and pedological methods has been used to study a late-Holocene sedimentary sequence in a rock coast sector from NW Spain, with the aim of relating it to storm events and their morphodynamic effects. The sequence contains two coarse beach layers at an elevation of 2.8–3.5 m above the present highest astronomical tide (HAT). Radiocarbon dating revealed that their deposition had begun during 1735–1590 cal. yr BP and has continued until the present. The entire beach system experienced considerable morphological change after 1320–1230 cal. yr BP, with a westward displacement of the beach and a retreat of the sedimentary cliff in the eastern section. The two beach layers seem to have been formed by vertical aggradation of clasts and sand during high-energy storm events, highlighting the role of these events in the formation of sedimentary sequences on the rocky coasts of mid-Atlantic Europe. The effects of a recent storm event, recorded in March 2008, and the results of wave calculations suggest that long swell waves were needed for the accretion of the clasts. Using a hindcast model of wave data, we found a positive correlation between the winter North Atlantic Oscillation (WNAO) index and the winter monthly mean wave height and peak period. While the 14C chronology of beach sedimentation coincides with known climatic periods dominated by a positive NAO index, these results point to the importance of high-energy events and the synergies between past and present processes in the recent evolution and the morphodynamics of rock coast environments.

Pedostratigraphy applied to urban archaeological coastal sites, combined with coastal geomorphological and archaeological data, provide important information for interpreting the complexity of coastal urban areas and their environment. This paper applies this methodology in the case of the Roman salt mines of Vigo, northwest Spain, and presents geomorphological and geoarchaeological data (stratigraphy, physicochemical soil properties, mineralogy, radiocarbon dating) for the museum where these remains are located. A 2000 year pedostratigraphic sequence was reconstructed, showing coastal evolution from beach to marshland. This change, along with more favorable climatic conditions related to the Roman Warm Period and dynamics associated with late Holocene rising sea level, created suitable conditions for the establishment of a salt mine. Geoarchaeological work is essential in archaeological excavations of modern urban areas, as demonstrated at Vigo where the study of pedostratigraphy provides crucial information on past environmental changes and human activities. Pedostratigraphic records and archaeological remains should be considered part of the geological and cultural heritage of urban areas. K E Y W O R D Scoastal evolution, NW Spain, Roman Period, salt mines, urban geoarchaeology