IMHICIHU   13380
Unidad Ejecutora - UE
congresos y reuniones científicas
Taphonomic studies of surface lithic scatters from the coastal area of San Matías Gulf, Río Negro province, Argentina
Congreso; 4th Southern Deserts Conference; 2014
Institución organizadora:
Laboratorio de Paleo-Ecología Humana, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo
The research area The coast of San Matías Gulf ?Río Negro province, Argentina- runs along 380 linear km and can be divided into two sectors, North and West, each with different geological and geomorphological characteristics, resulting in a differential space use by hunter-gatherers populations who occupied the area during the Middle and Late Holocene (ca. 6000-450 years BP). The temperate semi-arid climate predominates in the area with rainfall varying between 100 and 350 mm per year. The aeolian processes are the main materials transportation, erosion and redepositional agents and are a very important force of sorting and alteration of the archaeological record. These archaeological materials are located mainly in surface deposits being found in two different landforms with differential dynamic process -dunes and terraces-.Objectives and methodology The main goal of this paper is to present the methodology we used for analyzing the formational history of lithic scatters affected by surface erosion processes in our study area. Through the application of actualistic analysis and the statistical modeling we characterize lithic assemblages from different contexts of the northern coast of the Gulf. Taking into account the differences in resolution and integrity of the archaeological record, we explore patterns of differential exposition and preservation among the studied loci.To recover the artifacts we employed a distributional methodology in which the sample units were 2 m2 grids, where we recovered 958 artifacts. The sampling was done carrying out a taphonomic control, which involved marking the exposed face of each artifact in order to reconstruct the original position of each piece. To fulfill this objective we consigned: - face of recovery of each artifact (side A or B), - the abrasion stage of each face (W), - position change and relative stability - volume of each artifact. Also, we collected an assemblage redeposited by wind action. In order to compare different levels of weathering frequency we used a Chi2 test. Changes in position and relative stability were registered as dichotomic variables and were used in regression models along with the volume of each artifact. In all cases the level of significance was 0.05. Analysis and resultsThe comparison of weathering levels by area indicates significant differences among them, with certain loci with higher and lower frequency of different weathering levels. A significant correlation among volume and position change, and volume of the redeposited assemblages and volume of the archaeological ones was observed.DiscussionThe results suggest that the post-depositional history is different among the different loci. Some of them suggest a relatively recent exposure, as there is a predominance of the early stages of weathering on both sides. On the contrary, other assemblages show the predominance of higher weathering stages, which is consistent with the longer exposure of these materials on highly deflated terraces, forming pavements. The volume distribution of the lithic materials and of the redeposited assemblage together shows that both groups have different distribution. This along with what was observed in the redeposited scatters can be experimentally contrasted, generating certain criteria to evaluate position changes/burial and the differential removal of artifacts in relation to its volume. All this would indicate different levels of exposure and preservation according to artifacts depositional contexts. Therefore, the study of the consequences of these processes on the conformation of surface archaeological sites provides clues to interpret the redundancy in the space use over time.