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Multi-method absolute paleointensity determinations on a Pliocene multiple-polarity record from the Lesser Caucasus
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  • Elisa María Sánchez-Moreno,
  • Manuel Calvo-Rathert,
  • Avto Goguitchaichvili,
  • George T. Vashakedze,
  • Pierre C Camps,
  • Juan Morales,
  • Néstor Vegas,
  • Vladimir A. Lebedev
Elisa María Sánchez-Moreno
Universidad de Burgos

Corresponding Author:[email protected]

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Manuel Calvo-Rathert
Universidad de Burgos
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Avto Goguitchaichvili
Instituto de Geofisica, U.N.A. M.
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George T. Vashakedze
Alexandre Janelidze Institute of Geology - Ivane Javakhishvili Tbilisi State University
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Pierre C Camps
CNRS & Univ. Montpellier
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Juan Morales
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Néstor Vegas
Universidad del País Vasco (UPV/EHU)
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Vladimir A. Lebedev
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We report high technical quality absolute paleointensity determinations from a Pliocene sequence of 20 consecutive lava flows sampled in South Georgia named Apnia, which record either the Gilbert-Gauss polarity reversal or a composite transition from chron C2Ar to subchron C2An-2n. Paleointensity determinations with the multispecimen (MSP) technique were performed on 12 samples with both the original method (MSP-DB) and the extended protocol with corrections (MSP-DSC). Six MSP-DB and eight MSP-DSC determinations passed the proposed quality criteria. MSP-DB yielded higher intensity values than MSP-DSC. In order to provide additional reliability to the results, we have carried out a consistency test by means of a multi-method approach. We have compared the MSP intensities with Thellier-type intensities obtained from the reinterpretation of determinations performed in previous study. The match of both types of paleointensity determinations gives the results an added reliability. Paleointensity results have been obtained in all 20 flows, 11 of which were supported on different methods. At the reverse polarity lower section, low-VADM values between 2.1 and 4.2 x 10 Am were obtained. The single transitional flow displayed 4.3 x 10 Am, and the normal polarity upper section showed higher values between 5.1 and 7.1 x 10 Am. The lower section results might be a pre-reversal stage record and the upper section may reflect the intensity recovery after the complete reversal. Furthermore, the results comparison from both methods will allow the evaluation of the quality parameters proposed to MSP method, which are controversial given the novelty of the technique.