Weathering of Surficial Lithic Assemblages in the Hyperarid Core of the Atacama Desert, Chile


Surficial archaeological sites are widespread in arid environments. However, due to the difficulties in numerically dating them, they are usually considered as coarse indicators of past behaviors. Here, we explore the use of lithic weathering to develop local relative chronologies, and to better incorporate these assemblages into archaeological research. We test whether the most weathered artifacts should be considered the oldest; an assumption that has informally served to compare assemblages. Through macroscopic analyses, we compared seven surficial mid-to-late Holocene lithic assemblages from different micro-environments of the Atacama Desert, northern Chile. By recording changes in polish, texture, shine and color, we established that weathering varied significantly between two main locations: interfluve and canyon sites. Lithics from interfluve sites showed a dark coating and were moderately to highly weathered, whereas canyon lithics were mildly weathered and uncoated. This means that even within the hyperarid core of the Atacama, lithics of roughly the same age, are differentially weathered. We conclude that wind is the main weathering agent, mostly affecting artifacts deposited on inactive terraces or interfluves, where they remain persistently at the surface. Consequently, we stress the importance of considering taphonomic, geomorphologic and archaeological factors together when trying to establish relative chronologies.

Cite this Record

Weathering of Surficial Lithic Assemblages in the Hyperarid Core of the Atacama Desert, Chile. Paula Ugalde, Calogero Santoro, Eugenia M. Gayo. Presented at The 82nd Annual Meeting of the Society for American Archaeology, Washington, DC. 2018 ( tDAR id: 444616)

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Spatial Coverage

min long: -82.441; min lat: -56.17 ; max long: -64.863; max lat: 16.636 ;

Record Identifiers

Abstract Id(s): 20494