Geomorphological evolution of san antoniobay, province of Río Negro

Abstract:

In the San Antonio bay, province of Rio Negro, Argentina, marine deposits that crop out along the coast provide evidence of changes in sea level during the Quaternary. The main objective of this paper is to reconstruct the ancient coastal landscapes in the San Antonio bay using geomorphological techniques.The coastal area of the San Antonio bay is located between two Pleistocene spits: Punta Villarino, located to the east, and Punta Delgado located to the west, both composed by sandy gravel beach ridges and abundant mollusk remains.In the shadow of these spits, an environment of tidal flats and marshes is developed, whereas going northward, beyond the current tidal plain, a set of Holocene and Pleistocene beach ridges are found. The coastal strip is covered by mobile sand dunes up to 10 meters high, where abundant archaeological evidence is found. Radiocarbon dating were performed on fossil mollusks belonging to the environment of the beach ridges and bivalves, charcoal and fish remains from anthropogenic deposits. These deposits include evidence of ancient human populations who settled in this place since at least 6,000 years BP. From these data, a geomorphological map was drawn, postulating the evolutionary sequence of the area that was flooded several times during the Pleistocene about 64 ma.s.l. This paper also considers important to discuss the ages around 27,200 14C years BP and ages over 40,000 14C years BP obtained in beach ridges.

Año de publicación:

2017

Keywords:

• Sea level changes
• San antonio oeste
• Coastal prehispanic human occupation
• Pleistocene and holocene beach ridges

Fuente:

scopus