Geoarqueología en la estepa fueguina, Argentina. Efectos de los procesos geomorfológicos sobre material arqueológico de superficie

ORÍA, J.; VILLARREAL, M.L.; CORONATO, A.M.J.; SALEMME, M.; LÓPEZ, R.

Revista Geológica Española

Sociedad Geológica Española

Lugar: Salamanca; Año: 2014 vol. 27 p. 51 - 68

0214-2708

Abstract: Results from the geoarchaeological analyses carried out at two archaeological localities inthe hinterland steppe of Tierra del Fuego (southernmost Argentina), are herein presented. Processes ofseasonal running water, mass-wasting and aeolian erosion-accumulation occur over concentration ofscarce remains usually recorded at the surface. The two studied cases (the Amalia 5 site and the DunaO´Connor find) come from similar environments of shallow lake surroundings. Each case-study wasexposed to different geomorphological processes that altered not only each piece itself but also the integrityand resolution of the archaeological contexts. Wind and water were identified as the main agentsacting upon the archaeological remains. The lithic materials were analyzed following several indicators:raw material (lithology and texture), artifact size, percentage of cortex on the lithic surface, degreeof fragmentation and surface alteration (polishing and abrasion). Likewise, a detailed descriptionof the geomorphological setting and processes that took place in these sites was done, to identify the possiblelink between these processes and the characteristics of the archaeological record. The Amalia 5site is located within a gully excavated on aeolian deposits, some of them edaphized, and overlying finegrainsedimentary rocks and conglomerates. Collectors for sediments were installed, to control dimensionsof materials that could be blown by wind. In both localities topographic and stratigraphic profileswere surveyed using Total Station and a differential GPS. In spite of the differences related to the geomorphologicaland archaeological contexts, the results have shown strong similarities in the use of theraw materials, in the type of artifacts found and in the taphonomic processes that took place over theassemblages. Though both assemblages come from shallow lake environments, they were located in differentlandforms. The preservation of both contexts shows low variability concerning the degree of abrasionand polishing, depending on the dominant processes in each shallow lake shores (either runningwater or wind). From the view point of human occupation, the available lithic resources in both localitiesare different. The local geomorphology and/or the different availability of raw material, allowedto identify different ways in the use of space; whereas the gully of the Amalia 5 site should have been aplace where cobbles and pebbles were available for knapping artifacts (demonstrated by the high frequencyof recorded items), in the Duna O´Connor the space could have operated as a place to look foranimal resources, since lithic raw material was not available.