10Be flux in Antarctica during the last 800 000 years and interpretation
type: Distribution
access URL: https://theses.hal.science/tel-00954293
format: HTML
issued: 2026-05-06T04:24:22.853307
modified: 2026-05-06T04:24:22.808732

test_moissonnage_selune
type: Agent

10Be flux in Antarctica during the last 800 000 years and interpretation
type: Dataset
contact point: Organization
  fn: CCSD
keyword: climate
keyword: theses
keyword: antarctica
keyword: antarctique
keyword: infoeu-reposemanticsdoctoralthesis
keyword: beryllium-10
keyword: climat
keyword: ice-core
keyword: activite-solaire
keyword: sdustusciences-of-the-universe-physicsearth-sciences
keyword: earth-magnetic-field
keyword: carotte-de-glace
keyword: solar-activity
keyword: champ-magnetique-terrestre
landing page: https://theses.hal.science/tel-00954293
description: The polar ice cores, in addition to improving our understanding of the climate, give access to beryllium-10 (10Be) fallout, an isotope of cosmogenic origin created by the interaction of Galactic Cosmic Rays with the upper atmosphere. Its production rate depends on the intensity of the primary cosmic rays, which are modulated by solar activity and the Earth's magnetic field. 10Be therefore provides information on these two parameters. It has allowed, among others, the improvement of ice cores chronologies thanks to absolute stratigraphic markers linked to remarkable events of the geomagnetic field as the Laschamp excursion or the Brunhes-Matuyama reversal.EPICA Dome C (75° 06' S, 123° 21' E) is a 3270~m ice core drilled in East Antarctica. It offers a complete climate record over the last 800 000 years (kyr BP). In the framework of the PhD, 2200 10Be samples were measured between 2384 m (269 kyr BP) and 2627 m (355 kyr BP) deep. This continuous sequence provides, on the one hand, the opportunity to study the solar activity during the interglacial period of the Marine Isotope Stage (MIS) 9.3, where the resolution reaches ~20 years. Our results contrast with those during the Holocene, with the noted absence of the de Vries cycle (210 years) in our 10Be profile. On the other hand, this sequence allowed us to verify that the classical estimate of snow accumulation obtained by the dating models of ice cores is correct to within 20% during the succession of glacial – interglacial cycles.These measurements were combined with those previously performed under the responsibility of Grant Raisbeck (publication in preparation). This allows to dispose of a continuous and detailed profile (resolution: 20 to 250 years) between 200 and 800 kyr BP on the EPICA Dome C ice core. The observed 10Be flux variations compare well with changes in the intensity of the geomagnetic field recorded in marine sediments. From this observation, it is possible to propose a synchronization of these pr…
identifier: NNT: 2013PA112199
issued: 2026-05-06T04:24:22.823395
language: fr
modified: 2026-05-06T04:24:22.823401