Formation Processes and Environments in the Hinojo-Las Tunas Shallow Lake System, Argentina Pampas: The Laguna Chica Archaeological Locality as a Case Study

Abstract

This work integrates taphonomic (archaeofaunistics and bioarchaeology) and geoarchaeological (geormorphology, pedologic, sedimentological and micromorphological analyses) information to discuss the depositional and postdepositional history of both surface and buried archaeological record related to past hunter–gatherer populations from the Central Pampean Dunefields of Argentina (South America). Radiocarbon and optically stimulated luminescence dating suggest three temporal clusters of occupations in the Laguna Chica locality: one during the middle Holocene (~8050–6535 years cal. B.P.) and two in the late Holocene (~3350–2870 and ~1640–1535 years cal. B.P.). Middle Holocene burials found at the present lake shore are hosted in aeolian sediments that accumulated under arid/semiarid conditions. Modern lacustrine dynamics derived from contraction/expansion cycles have exposed burials, archaeofauna, and stone tools, resulting in displacements, fragmentation and loss. A palimpsest of cultural and natural material spanning ~8000 years resulted from this paleoenvironmental setting. Late Holocene human activities might have been related to a transitional landscape, where aeolian processes took place under an expanding lacustrine scenario (i.e., relatively wetter conditions). Our stratigraphic assessment suggests that human occupations were syndepositional agents with episodes of aeolian sand activity and landscape stability. The taphonomic and geoarchaeological evidence from Laguna Chica locality show that the empirical evidence traditionally used to evaluate hunter–gatherer settlement patterns (e.g., abundance and diversity of archaeological evidence and their spatial association in surface or stratigraphic units) and human diet breadth changes (e.g., Ntaxa) may simply reflect the cumulative action of lacustrine erosion of dunes. While both the Laguna Chica surface and stratigraphic records have complex formation histories, the buried context could be interpreted with greater detail through taphonomic and sedimentological analyses.