The Late Quaternary landscape history of the Middle Rio Negro Valley, northern Patagonia, Argentina: its impact on preservation of the archaeological record and influence on Late Holocene human settlement patterns

Abstract

Geoarchaeological investigations were conducted in the Middle Río Negro Valley in the northern portion of Patagonia, Argentina from 2004-2005. This project worked in conjunction with archaeological investigations in this region conducted by Lic. Luciano Prates (Universidad Nacional de La Plata, Argentina). No previous studies on the detailed reconstruction of the landscape history had been conducted in this valley. In order to place the archaeological record in this landscape context, this project had four main research objectives: 1) to reconstruct the landscape history; 2) to incorporate the known archaeological record into this landscape history; 3) to interpret natural formation processes and evaluate the preservation potential for archaeological sites; and 4) to interpret how landscape history could have influenced settlement patterns. Altogether, six months of fieldwork consisted of field reconnaissance of the landscape and recording of the regional stratigraphy through detailed analysis of sediments and soils, geomorphological features, and archaeological sites. This fieldwork was combined with analysis of aerial photographs, topographical and geological maps, and sedimentological samples, in addition to the incorporation of radiocarbon and optically stimulated luminescence dating of stratigraphic units. As a result, through landscape reconstruction, it was possible to evaluate the preservation of the archaeological record, its landscape context, and to construct a predictive model for the location of archaeological sites from the Late Pleistocene through Late Holocene. Study of Late Holocene channel avulsion and the formation of pools within abandoned avulsion channels which occurred in one part of the study area suggest that landscape change potentially influenced Late Holocene settlement patterns in the Middle Río Negro Valley.