Raw material sourcing in the Middle Paleolithic site of Gruta da Oliveira (Central Limestone Massif, Estremadura, Portugal)

Henrique Matias

doi:10.2218/jls.v3i2.1452

Abstract

The cave site of Gruta da Oliveira is located in the Almonda karst system, at the interface between the Central Limestone Massif of Portuguese Estremadura (CLM) and the adjacent Sedimentary Basin of the River Tagus (TSB). The cave presents a stratification dated to ~37-107 ka containing hearth features, Neanderthal skeletal remains, as well as fauna, microfauna and wood charcoal remains. The lithic assemblages are large and feature a diverse range of raw materials.Knappable lithic raw materials in primary, sub-primary and secondary position in the CLM and the TSB were systematically surveyed and sampled. The characterization of the geological samples was carried out at both the macro- and the microscopic scales and data were systematized under the petroarcheological and “evolutionary chain of silica” approaches.The study of the lithic assemblage from layer 14 (dated to the ~61-93 ka 95.4% probability interval by TL) indicates that the Gruta da Oliveira Neanderthals used quartzite, quartz and flint from sources located less than 30 km away in both the CLM and the TSB.

Highlights

The Almonda karst system, an extensive network of cavities associated with the spring of the River Almonda, is located in the Meso-Cenozoic Western Border (MCWB) of Iberia, at the boundary between the Central Limestone Massif (CLM) and the Tagus Sedimentary Basin (TSB)
As the Almonda karst system is located at the boundary between the CLM and the TSB, the raw materials used by the Gruta da Oliveira Neanderthals reflect their natural availability within these two different structural units
In the CLM, in situ and sub-primary Middle and Late Jurassic flint sources are found in geographically restricted outcrops or deposits, while the Miocene plains of the Tagus Basin feature widespread Cenozoic and Quaternary siliciclastic deposits with quartzite, quartz, doi:10.2218/jls.v3i2.1452

Summary

Introduction

The Almonda karst system, an extensive network of cavities associated with the spring of the River Almonda, is located in the Meso-Cenozoic Western Border (MCWB) of Iberia, at the boundary between the Central Limestone Massif (CLM) and the Tagus Sedimentary Basin (TSB). Among those of archeological interest, the lowermost passages, 5-15 m above the current spring, contain deposits of Upper Paleolithic and later prehistoric age (Almeida et al 2004; Angelucci & Zilhão 2009; Zilhão 1997) (Figure 1).

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