Erosion in the Patagonian coast by climatic change

Abstract

Hydraulic conditions for gravel transport are not present in the main rivers of Patagonia. The accretion gravel landforms on the coast are relictic, due to the lack of gravel input by present rivers. Erosion is primarily caused by the lack of direct accumulation (the river load does not reach the coastline) and by induced erosion (since littoral drift is not saturated from river input, erosive processes operate on the coastal outcrops). The base level of the Pleistocene rivers, in several occasions, was about 150 m under the present base level, thus the presence of submerged coastlines is explained by the imput of abundant fluvial material from that period. Not only a sea level lowstand but also a climatic change can be inferred by the presence of submarine canyons in the continental shelf, which are the continuation of river valleys below present sea level.