Magnetic investigations of buried palaeo-hearths inside a palaeolithic cave (Lazaret, Nice, France)

Journal Article

Jrad, A. . 2014

• رابط المنشور على الويب: http://wileyonlinelibrary.com
• المجلة \ الصحيفة: Archaeological Prospection
• رقم الإصدار السنوي: 21
• الصفحات: 87-101

مستخلص المنشور

We present a magnetic study of palaeohearths within Lazaret cave (Nice, France) that demonstrates how to recognize
fired structures in similar geological contexts. Using magnetic field and susceptibility mapping, excavated and
potentially still-buried palaeohearths of the cave are investigated. Our study reveals some difficulties in conducting
a magnetic field survey to detect combustion features in a cave due to noise and ambiguities in anomaly assignment.
To overcome these difficulties, discrete measurements and a specific post-processing methodology were applied to
remove the magnetic noise generated by surrounding artificial sources. In addition, experimental and numerical
modelling constrained by laboratory examinations of the magnetic mineralogy were performed to better identify the
magnetic imprint of such fireplaces. We confirm that a short-term fireplace produces a thin ash-bearing layer characterized
by a high magnetic susceptibility and a high frequency dependence due to a large proportion of grains of
pseudo-single-domain (PSD) size. Such a burnt soil layer is the main source of the ca. 50 nT amplitude magnetic field
anomaly at a sensor height of 15 cm observed over the excavated palaeohearth, as well as over an experimental
hearth.