Abstract

The regressive barrier (strandplain) of Tongoy is a complex system of coastal landforms, composed of foredunes, beach ridges and semipermanent streams that together have shaped the actual lagoons. This research aims to contribute to the knowledge of these features in the tectonic active western continental margin of South America and analyzes their evolution in the development of the regressive barrier of Tongoy Bay. A geomorphological survey was conducted, between the Pleistocene marine terraces and the modern shoreline; aerial photographs from different years were used, observing changes over the barrier surface, estuaries and lagoons. From the identified forms it is concluded that the barrier corresponds to an accretion system, which together with the development of beach ridges has evolved into a regressive barrier system. It is still possible to find abandoned lagoons behind the present lagoons. Currently, accretion conditions are demonstrated by the preservation of foredunes and embryonic dunes.