Barranca de los Concheros Locality: a unique outcrop of interstratified shellmiddens in a 360m long and 20m high profile discovered in Nothern Patagonia, Argentina

FAVIER DUBOIS, CRISTIAN M; LANZELOTTI, SONIA L.

Ciudad de México, México

Simposio; International Council of Archaeozoology (ICAZ 2006); 2006

Instituto Nacional de Antropología e Historia, México.

Recent archaeological surveys in Northern Patagonia Atlantic Coast (Rio Negro Province, Argentina) have favoured the discovery, in a Tertiary cliff, of an extended Holocene Aeolian profile that is 360 metres long and 20 metres high where hundreds of interstratified shellmiddens are observed. The first sample comprised 25 metres of the profile mentioned above, where 17 superimposed lenses were recorded; the vertical separation between the higher and the lower one was of 13 metres. The lens width ranges from 5 cm to 12 cm and the length from 0.70 m to 9 m and they present a high horizontality. The species present are Aulacomya Ater and Mytilus edulis, and, in a smaller proportion, Brachiodontes rodriguezi.  Charcoal and ashes are observed among the shells in every assemblage and the more developed lenses include lithic artifacts, though they are scarce. The matrix yielded evidence of primary sedimentary structures in some areas of the profile, which would indicate high depositional rates that may have favoured the excellent preservation state of these anthropic accumulations. The dates obtained from charcoal found in the upper and lower lenses within the analysed area are of ca. 2800 years AP and ca. 1800 years AP, respectively, indicating an only 1000 years span in a 13 m sedimentary thickness. On account of its characteristics this site is unique in the Patagonian Coast as it owns great potential to conduct detailed studies about the intensity and exploitation mode of coastal resources in the Late Holocene on behalf of the North Patagonia hunter-gatherers, as well as to implement high resolution paleoecological and paleo-environmental analyses that are currently being developed.