Evidence for multiple paleomagnetic intensity lows between 30 and 50 ka BP from a western Equatorial Pacific sedimentary sequence

• Published in: Quaternary Science Reviews
• Main Authors: Blanchet, Cl, Thouveny, Nicolas, de Garidel-Thoron, Thibault
• Other Authors: Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: MONO LAKE EXCURSION; GEOMAGNETIC MOMENT VARIATIONS; NORTH-ATLANTIC; PALEOINTENSITY STACK; LASCHAMP EXCURSION; PORTUGUESE MARGIN; POLARITY EVENT; SUMMER LAKE; AGE; RECORD; Geography; Physical; Geosciences; Multidisciplinary; Physical Geography; Geology; 0277-3791; [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]; [SDE.MCG]Environmental Sciences/Global Changes; Pacific; North Atlantic
• Online Access: https://hal.science/hal-00869241; https://doi.org/10.1016/j.quascirev.2005.09.001

A paleomagnetic study was carried out on the radiocarbon dated MD97-2134 core located in the western Equatorial Pacific (Southern Papua New Guinea margin). Rock magnetic investigations revealed changes of the magnetic mineralogy along the hemi-pelagic sedimentary sequence but the reconstruction of past direction and relative paleointensity variations of the geomagnetic field remained feasible. Four successive paleointensity drops are recorded between 30 and 50 ka BP. The largest one is associated with an abrupt swing of declination and inclination interpreted as a smoothed signature of the Laschamp excursion (similar to 41 ka BP). The Succession of four events of weak intensity between 30 and 50 ka BP introduces a complex behaviour of the geomagnetic field in the time interval spanning over the Laschamp and the Mono Lake excursions. (c) 2005 Elsevier Ltd. All rights reserved.