Management of ambiguities in magnetostratigraphic correlation

Autor: Julien Charreau, Guillaume Caumon, Christophe Antoine, Jeremy Ruiu, Florent Lallier
Přispěvatelé: GeoRessources, Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Institut national des sciences de l'Univers (INSU - CNRS), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Association Scientifique pour la Géologie et ses Applications (ASGA)
Jazyk: angličtina
Rok vydání: 2013
Předmět:
Zdroj: Earth and Planetary Science Letters
Earth and Planetary Science Letters, Elsevier, 2013, 371, pp.26-36. ⟨10.1016/j.epsl.2013.04.019⟩
ISSN: 0012-821X
DOI: 10.1016/j.epsl.2013.04.019⟩
Popis: International audience; Magnetostratigraphy is a powerful tool to provide absolute dating of sediments enabling robust and detailed chronostratigraphic correlations. It is based on the correlation of a magnetic polarity column, observed and measured in a given sediment section, to a magnetic polarity reference scale where polarity changes are well dated via other independent methods. However, magnetostratigraphic correlations are loose as they are only constrained by binary magnetic chrons (i.e. normal or reversal) and their thickness, which are both defined from depth variations of the magnetic remanent directions. The thickness of a given magnetic polarity zone is a function of time and sediment accumulation rate, which may not be stationary, leading to ambiguities when performing the correlations. To address these ambiguities, a numerical method based on the Dynamic Time Warping algorithm is proposed. Magnetostratigraphic correlations are computed in order to minimise the local variation of the accumulation rate. The main advantage of the proposed method is to automatically provide a set of reasonably likely correlations. This set can then be scrutinised for further analysis and interpretation. However, the likelihood of a correlation should be handled carefully as it depends on the information content of the magnetostratigraphic section itself and remain ultimately valid by ancillary constraint. Nevertheless, the method gives consistent results on difficult synthetic cases that simulate abrupt variations of the sedimentation rate. Insights on true sections debated by previous authors are also given.
Databáze: OpenAIRE
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