Rockmagnetic based environmental reconstruction of Galería and Gran Dolina caves in Sierra de Atapuerca (Burgos, Spain)

Abstract

Magnetic properties of sediments can furnish an environmental reconstruction of the deposition time. In our study we intend to understand the climatic – paleoenvironmental conditions at the time the earliest hominins found in Europe, and especially the well-known archaeological sites at Sierra de Atapuerca, in Burgos, Spain. The sites assemblage is found in a multi-layered karstic system, and includes a number of caves filled with both interior (distal) and entrance sediments. We focused our attention on two caves, which belong to the so-called “Trinchera” (trench) sites, namely Galería and Gran Dolina. The latter has produced thousands of fossils and artefacts since 1995, when the first hominin remains were reported, and soon became a Pleistocene landmark in studies on early human settlement outside the African continent. Our already published study on Gran Dolina presents more variability of magnetic properties in cave-entrance sediments than in the cave-interior, as expected for the exterior influence on the grain size and iron oxides concentration.

Now, we start to investigate the Galería site to correlate it with the nearest cave and to better understand the paleoenvironmental context at the time early humans inhabited the area. In particular, we confined our attention to identify the magnetic minerals present into Covacha de los Zarpazos (the lower studied part of Galería) with backfield and IRM curves determined by a magnetic Variable Field Translation Balance (VFTB). This analysis allows us to individuate a more precised reconstruction of the environmental conditions of the deposition time, also with a comparison of a pollen study and X-Ray Fluorescence (XRF) in-situ study for a major precision.