Geological changes in coastal areas of Patagonia, Argentina and Chile

Abstract

The Patagonian coast evolved in relation to different issues. An arid climate dominates to the north, while very humid conditions prevail to the south of the Pacific coast and at the Fuegian archipelago. Tidal effects increase from north to south at the Atlantic coast, while the Pacific coast is dominantly microtidal. Patagonia has been uplifting in relation to the Andes mountains; at the Atlantic coast, the uplift increases toward the south. Marine terraces originated by the Quaternary sea-level fluctuations that developed in response to the sediment availability. The cliffy Atlantic coast is receding at a rate between 0.3 and 1.4 m yr.−1. Reversals in the direction of river discharges changed the supply of sediment to the coast; dams constructed at the piedmonts also caused these sediment shortages. Gravel availability contributed to the armoring of beaches and the longshore growing of spits. In many places, these barriers are protecting marshes and tidal flats against the sea level rise.