2026-07-26T04:07:31Zhttps://riubu.ubu.es/oai/request

oai:riubu.ubu.es:10259/101672025-02-06T01:05:23Zcom_10259.4_2560com_10259_5086com_10259_2604col_10259.4_2561

Calvo Rathert, Manuel Vernet Tarrago, Eva Parés Casanova, Josep M. Soler, Vicente Sánchez Moreno, Elisa María Bógalo Román, Mª Felicidad Carrancho Alonso, Ángel Yamamoto, Yuhji Rodríguez Méndez, Lidia 2025-02-05T07:48:19Z 2025-02-05T07:48:19Z 2024 0956-540X http://hdl.handle.net/10259/10167 10.1093/gji/ggae297 1365-246X A basaltic lava flow erupted from the Tajogaite volcano on 4 December 2021, in La Palma (Canary Islands, Spain) was sampled to find out to what extent reliable and correct information on both intensity and direction of the Earth's magnetic field can be obtained from the palaeomagnetic signal recorded in a lava flow which erupted under known conditions. Samples were taken every few centimetres across a flow up to a total of 27 oriented cores. Palaeomagnetic experiments showed a strong viscous overprint in many samples. Nevertheless, the mean palaeomagnetic direction obtained agrees well with the actual value from IGRF-13. Rock magnetic experiments were performed to obtain additional information about the quality and reliability of the results and the reasons for unsuccessful determinations. Analysis of mostly irreversible thermomagnetic curves showed that the carriers of remanence were magnetite and titanomagnetite of low and/or intermediate Curie-temperature. Hysteresis parameter ratios showed a pronounced variability across the flow. Analyses of frequency dependent susceptibility, IRM acquisition coercivity spectra and FORCs showed a noticeably presence of very low coercivity grains (multidomain and superparamagnetic-single domain boundary). Multimethod palaeointensity experiments were performed with the Thellier-Coe, multispecimen and Tsunakawa-Shaw methods. Only three of 25 cores from the flow yielded successful Thellier-Coe determinations, in agreement with the expected field value of 38.7 μT (IGRF-13). However, palaeointensities of 60 per cent of the specimens agree with the expected value performing an informal analysis without considering criteria thresholds. Four of six Tsunakawa-Shaw determinations performed on samples from the flow yielded correct results, but three multispecimen determinations providing apparently successful determinations largely underestimate the expected field intensity. Combination of three Thellier-Coe and four Tsunakawa-Shaw successful determinations yields a multimethod palaeointensity result B = (36.9 ± 2.0) μT in good agreement with the expected field intensity. This work was funded by project PID2019-105796GB-100/AEI/10.13039/501100011033 (Spanish Agencia Estatal de Investigación), project BU037P23 (Junta de Castilla y León and the European Research and Development Fund, ERDF) and JSPS KAKENHI Grant No. 21H01171. We thank Antonio González (Cabildo de La Palma) for his invaluable support and help during our visit to the island of La Palma. We also wish to thank Dr Eugenio Fraile Nuez (IEO-CSIC) for providing us the submarine lava flow samples. We also wish two thank two anonymous reviewers for helpful comments. application/pdf eng Oxford University Press Geophysical Journal International. 2024, V. 239, n. 2, p. 841-861 https://doi.org/10.1093/gji/ggae297 Atribución 4.0 Internacional http://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess Palaeointensity Rock and mineral magnetism Palaeomagnetism Oceanic hotspots and intraplate volcanism Paleomagnetismo Paleontología Magnetismo Arqueología Paleomagnetism Paleontology Magnetism Archaeology Reliability of the palaeomagnetic signal recorded in a lava flow erupted on 4 December 2021 in La Palma (Canary Islands, Spain) info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Geophysical Journal International 239 2 841 861