Palaeotopography of a Palaeolithic landscape at Bestwood 1, South Africa, from ground-penetrating radar and magnetometry

Konstantinos S Papadimitrios,Carl-Georg Bank,Michael Chazan,Steven J Walker

doi:10.17159/sajs.2019/4793

Konstantinos S Papadimitrios, Carl-Georg Bank + Show 2 more

Open Access

https://doi.org/10.17159/sajs.2019/4793

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Abstract

In order to investigate the buried landscape at the Fauresmith locality of Bestwood 1, outside the town of Kathu in the Northern Cape Province, we performed ground-penetrating radar and magnetometry surveys across the sand-filled central portion of the valley. The radar images a strong continuous reflector which we can assign to the boundary between the Kalahari sands and underlying Banded Ironstone Formation gravels. Moreover, the thickness of the sand delineates a buried depression in the centre of the valley with flat plateaus at the sides. Subtracting the sand thickness from the current topography produces a map of a small stream channel in the northern part of the valley. Analysis of the magnetic gradient data allows us to extend this buried channel further to the south. Our geophysical survey provides a valuable contribution towards understanding the context of hominin occupation along the banks of a small stream in the Kathu Complex. Significance:  We provide an example of combining two geophysical methods to map overburden thickness, useful for archaeological landscape interpretation.  .

Highlights

The Kathu Complex is a series of archaeological localities – Kathu Pan, Kathu Townlands and Bestwood – that together represent evidence of extraordinarily intensive occupation through the Earlier Stone Age (Acheulean) and the transitional Earlier Stone Age to Middle Stone Age (Fauresmith).[1,2,3,4] The sheer scale of these localities is unusual and poses challenges for both research and conservation.In the research presented here, ground-penetrating radar (GPR) and magnetic gradiometer surveys were conducted to create a 3D subsurface map of the buried Pleistocene landscape at the site of Bestwood 1
The GPR transects produced a clear signal of the contact between the Kalahari sands and the underlying gravels
We had not planned at the outset of this study to combine magnetic and GPR surveys, and instead ran separate surveys

Summary

Introduction

The Kathu Complex is a series of archaeological localities – Kathu Pan, Kathu Townlands and Bestwood – that together represent evidence of extraordinarily intensive occupation through the Earlier Stone Age (Acheulean) and the transitional Earlier Stone Age to Middle Stone Age (Fauresmith).[1,2,3,4] The sheer scale of these localities is unusual and poses challenges for both research and conservation.In the research presented here, ground-penetrating radar (GPR) and magnetic gradiometer surveys were conducted to create a 3D subsurface map of the buried Pleistocene landscape at the site of Bestwood 1. The study site, Bestwood 1 (27°42′S 23°03′E, UTM zone 34 S), is situated in a south-facing valley in an isolated hill infilled with Kalahari sands. This hill is located at the western edge of the Kuruman Hills where this formation grades into the southern edge of the Kalahari Basin[3,4] (Figure 1). Valley walls slope gently and are composed of Banded Ironstone Formation (BIF) bedrock overlain by scree consisting of flat weathered slabs of BIF that includes large numbers of stone tools. The boundary between the scree deposits on the hill slopes and the sand infill is gradual and sand has infiltrated between the BIF slabs in the lower slopes

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