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oai:riubu.ubu.es:10259/61082022-11-29T08:42:41Zcom_10259.4_2560com_10259_5086com_10259_2604col_10259.4_2561

2021-11-05T09:14:10Z urn:hdl:10259/6108 Weak palaeointensity results over a Pliocene volcanic sequence from Lesser Caucasus (Georgia): transitional record or time averaged field? Sánchez Moreno, Elisa María Calvo Rathert, Manuel Goguitchaichvili, Avto Tauxe, Lisa . Vashakidze, George T. Lebedev, Vladimir A. Palaeointensity Magnetic field variations through time Palaeomagnetism A palaeointensity study has been carried out on a Pliocene sequence of 20 consecutive lava flows where previous directional results seem to reflect anomalous behaviour of the Earth’s magnetic field (EMF), which can be explained by a polarity transition record or non-averaged palaeosecular variation or both. Here, we perform a total of 55 palaeointensity determinations using the original Thellier–Thellier (TT) method and 100 with the IZZI method.We assess the performance of our selection criteria using a set of strict threshold values applied to a set of test data whose TRMs were acquired in known fields. Absolute palaeointensity determinations that passed our selection criteria were obtained on four specimens with the TT method and on 41 specimens with the IZZI method. Application of reliability criteria at a site level yielded palaeointensity results in 8 of 20 studied lava flows. We obtained median values of VADM between 28.9 and 45.6 ZAm2 for the reverse polarity lower Apnia section, while the normal polarity upper section displayed a single value of 54.6 ZAm2. The low palaeointensity values before a transitional direction lava flow and the higher value after it, suggest the common behaviour at the start of a polarity reversal and the recovery after it. However, an isolated record of a stable EMF, where the intensity is lower than the current for the same location (83.7 ZAm2), cannot be discarded. Consequently, this interpretation would support a weak time-averaged field. 2021-11-05T09:14:10Z 2021-11-05T09:14:10Z 2020-03 info:eu-repo/semantics/article 1365-246X http://hdl.handle.net/10259/6108 10.1093/gji/ggz533 eng Geophysical Journal International. V. 220, n. 3, p. 1604–1618 https://doi.org/10.1093/gji/ggz533 info:eu-repo/grantAgreement/MINECO//CGL2012-32149/ES/VARIACION DE LA PALEOINTENSIDAD ABSOLUTA DEL CAMPO MAGNETICO TERRESTRE REGISTRADA EN ROCAS VOLCANICAS: MOMENTO DIPOLAR, TRANSICIONES DE POLARIDAD Y SUPERCRONES info:eu-repo/grantAgreement/Junta de Castilla y León//BU066U16//Estudio arqueomagnéticos y de propiedades magnéticas en registros de fuegos antrópicos prehistóricos. Aplicaciones a la arqueología info:eu-repo/grantAgreement/MINECO//BES-2013-064060 info:eu-repo/grantAgreement/NSF//EAR1345003 info:eu-repo/semantics/openAccess Oxford University Press