Magnetic Alteration of Soils by Late Holocene Hunter-Gatherer Groups (Tierra Del Fuego, South America)

OZÁN, I.L.; NASELLI, M.; VÁSQUEZ, C.; ORGEIRA, M.J.

ARCHAEOMETRY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017

0003-813X

The present work aims to analyse the magnetic signature from the Late Holocene open-air archaeological deposits of hunter-gatherer ephemeral occupations. For this purpose, two profiles were sampled at the Marazzi 2 site in the north-western Isla Grande de Tierra del Fuego, Chile, in order to carry out studies of magnetic susceptibility, hysteresis cycles, back-field remanent magnetization, isothermal remanent magnetization and thermal variation of magnetic susceptibility at high and low temperature. Despite short-term occupations, the P1 profile shows a magnetic peak at a depth of ~30-70cm due to magnetite, probably formed by anthropogenic activity related to combustion. The P2 profile instead yields an anomalous peak of coercivity (at a depth of 20-40cm), which could also be anthropogenic, due to the presence of finely dispersed ancient ´red ochre´. The red ochre is proposed to form anthropogenic thermal alteration of goethite associated with volcanic ash, the remnants of which were found in thin sections from the P2 subsoil.