A revised, Last Interglacial chronology for the Middle Palaeolithic sequence of Gruta da Oliveira (Almonda karst system, Torres Novas, Portugal)

João Zilhão,Diego E Angelucci,Lee J Arnold,Martina Demuro,Dirk L Hoffmann,Alistair W.G Pike

doi:10.1016/j.quascirev.2021.106885

Abstract

Based on previous radiocarbon and U-series (Diffusion/Adsorption) dating of bone samples, the Middle Palaeolithic has been thought to persist at Gruta da Oliveira until ∼37 thousand years (ka) ago. New U-series ages for stratigraphically constraining speleothems, coupled with new luminescence ages for sediment infill, show that the site’s ∼6 m-thick archaeological stratigraphy dates entirely within a <30 ka interval spanning substages 5a-5b of Marine Isotope Stage (MIS) 5. Significant technological change is observed across the sequence, akin to that seen in the Upper Palaeolithic over similar timescales. Flake-cleavers and bifaces, normatively definitional of the Vasconian facies, are restricted to a short interval correlated with Greenland Stadial (GS) 22, 85.1–87.6 ka ago. In cave and rock-shelter sites of southern and western Iberia, intact archaeological deposits securely dated to the ∼37–42 ka interval remain elusive. Geological dynamics (e.g., erosion, sedimentation hiatuses, palimpsest formation) and human adaptive responses to climate-driven environmental change (e.g., abandonment of now forest-covered low- and mid-altitude karst areas, concentration of settlement in alluvial plains and coastal settings) are possible explanations for this pattern.

Highlights

The hypothesis that the Middle Palaeolithic persisted in Iberia long after the Upper Palaeolithic began elsewhere in Europe was proposed by Vega (1990) and Villaverde and Fumanal (1990) and developed into the “Ebro Frontier” model by Zilh~ao
The age of the archaeological sequence is constrained by two dated speleothems: the flowstone sampled by X1892 provides the terminus ante quem; the base of Crivo 1, a stalagmite growing out of the crust capping the sedimentary infill of the Passage of the Sieve, ~9 m lower down in Gruta da Oliveira’s system of interconnected passages (Fig. 1C, S6; Table S1), provides the terminus post quem
A maximum age is provided by the older limit, 107.1 ka, of the probability interval obtained for the base of Crivo 1 (104.4 ± 2.7 ka; Fig. 2A)

Summary

Introduction

The hypothesis that the Middle Palaeolithic persisted in Iberia long after the Upper Palaeolithic began elsewhere in Europe was proposed by Vega (1990) and Villaverde and Fumanal (1990) and developed into the “Ebro Frontier” model by Zilh~ao (1993, 2000, 2006a, 2009).

Methods

Results

Discussion

Conclusion