Author, as appears in the article.: Carrancho Á; Bradák B; Herrejón-Lagunilla Á; Vergès JM
Department: Història i Història de l'Art
URV's Author/s: Vergès Bosch, Josep Maria
Keywords: Archaeological fire Experimental archaeology Fumier Paleotemperatures Secular variation Taphonomy
Abstract: The improvement of the archaeomagnetic dating method requires compiling new and older data of the Earth's magnetic field (EMF) variations for the last millennia. Combustion events from fumier sequences have been proposed as good directional EMF recorders. However, they are subjected to diverse taphonomical processes and how these affect the archaeomagnetic record has not yet been studied. In order to evaluate it, here we report the first archaeomagnetic and rock-magnetic results on samples from experimentally recreated fumiers since 2014 under controlled conditions. A facies description with unprecedent resolution was used to study the variation of magnetic properties in depth. Rock-magnetic analyses indicate a homogenous magnetic mineralogy dominated by pseudo-single domain magnetite as main carrier in all facies, with not very high and similar contribution of the finest (superparamagnetic) grains. The low values of anisotropy of magnetic susceptibility (AMS) indicate that the studied sample set is mainly isotropic. The directional behaviour in well-preserved burned facies (here described as G, LM and DGB), are jointly characterized by highly reversible thermomagnetic curves, high Koenigberger (Qn) ratio values and intense, univectorial and normal polarity orthogonal NRM demagnetization diagrams. On the contrary, specimens affected by mechanical alteration processes are less magnetic and show anomalous directional behaviours. The high thermomagnetic reversibility of ashes indicates that they reached ca. 600–700 °C, in line with the thermocouples’ data. Temperatures of 460 °C were obtained for the DGB facies (subyacent black carbonaceous facies). Sampling of ashes located on the top of these combustion events should be avoided for archaeomagnetism. Being just beneath the last stabling episode they are the most prone to undergo mechanical alterations and do not preserve well the Earth's magnetic field direction. Despite their unlithified nature and the multiple taphonomic processes that fumier sequences may undergo, under certain quality criteria, they are valid geomagnetic field recorders providing both information of archaeological and geophysical interest.
Thematic Areas: Antropologia / arqueologia Archaeology Astronomia / física Biodiversidade Ciência da computação Ciências agrárias i Ciências ambientais Ciências biológicas i Ciências biológicas iii Ciencias humanas Earth-surface processes Engenharias ii Engenharias iii Engenharias iv Ensino Geociências Geografía Geography, physical Geosciences, interdisciplinary Geosciences, multidisciplinary Historia Historia y filosofía de la ciencia Interdisciplinar Medicina ii Odontología Saúde coletiva Zootecnia / recursos pesqueiros
licence for use: https://creativecommons.org/licenses/by/3.0/es/
Author's mail: josepmaria.verges@urv.cat
Record's date: 2023-10-07
Papper version: info:eu-repo/semantics/publishedVersion
Papper original source: Quaternary International.
APA: Carrancho Á; Bradák B; Herrejón-Lagunilla Á; Vergès JM (2023). Archaeomagnetic analyses on fumiers burned under controlled experimental conditions. Quaternary International, (), -. DOI: 10.1016/j.quaint.2023.09.005
Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
Entity: Universitat Rovira i Virgili
Journal publication year: 2023
Publication Type: Journal Publications
Repositori URV