RT info:eu-repo/semantics/article
T1 Weak palaeointensity results over a Pliocene volcanic sequence from Lesser Caucasus (Georgia): transitional record or time averaged field?
A1 Sánchez Moreno, Elisa María
A1 Calvo Rathert, Manuel
A1 Goguitchaichvili, Avto
A1 Tauxe, Lisa .
A1 Vashakidze, George T.
A1 Lebedev, Vladimir A.
K1 Palaeointensity
K1 Magnetic field variations through time
K1 Palaeomagnetism
K1 Magnetismo
K1 Magnetism
K1 Geología
K1 Geology
AB A palaeointensity study has been carried out on a Pliocene sequence of 20 consecutive lavaflows where previous directional results seem to reflect anomalous behaviour of the Earth’smagnetic field (EMF), which can be explained by a polarity transition record or non-averagedpalaeosecular variation or both. Here, we perform a total of 55 palaeointensity determinationsusing the original Thellier–Thellier (TT) method and 100 with the IZZI method.We assess theperformance of our selection criteria using a set of strict threshold values applied to a set oftest data whose TRMs were acquired in known fields. Absolute palaeointensity determinationsthat passed our selection criteria were obtained on four specimens with the TT method and on41 specimens with the IZZI method. Application of reliability criteria at a site level yieldedpalaeointensity results in 8 of 20 studied lava flows. We obtained median values of VADMbetween 28.9 and 45.6 ZAm2 for the reverse polarity lower Apnia section, while the normalpolarity upper section displayed a single value of 54.6 ZAm2. The low palaeointensity valuesbefore a transitional direction lava flow and the higher value after it, suggest the commonbehaviour at the start of a polarity reversal and the recovery after it. However, an isolatedrecord 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 weaktime-averaged field.
PB Oxford University Press
SN 1365-246X
YR 2020
FD 2020-03
LK http://hdl.handle.net/10259/6108
UL http://hdl.handle.net/10259/6108
LA eng
NO Project CGL2012-32149 (Ministeriode Economía y Competitividad, Spain), project BU066U16 (Juntade Castilla y León, Spain), pre-doctoral grant BES-2013-064060(Ministerio de Economía y Competitividad, Spain) and by NationalScience Foundation (USA) grant EAR1345003.
DS Repositorio Institucional de la Universidad de Burgos
RD 26-abr-2024