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| Titel |
Large ice-wedge networks and tundra gley horizons in Northern France Upper Pleistocene loess: evidences of extreme cold events and cyclic millennial changes |
| VerfasserIn |
Pierre Antoine, Olivier Moine, Gilles Guerin |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250112178
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| Publikation (Nr.) |
 EGU/EGU2015-12335.pdf |
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| Zusammenfassung |
| Northern France loess-palaeosol sequences from the last interglacial-glacial cycle (Eemian-Weichselian) have been intensely studied during the last 20 years (about 100 individual sequences). Despite thickness variations of the different stratigraphic units, the sequences from the last interglacial-glacial cycle exhibit a particularly constant pedosedimentary pattern, including well-identified pedological and periglacial marker horizons that can be followed north- and eastward in Belgium and Germany. Within this system, new field investigations and luminescence (OSL) datings put in evidence at least four generations of large ice-wedge networks (10-14 m) preserved by loess deposits between ca. 50 and 20 ka. The best- and most systematically preserved network is presently dated at about 31-32 ka according to the OSL ages from its loess infilling. This main ice-wedge cast horizon systematically occurs at the boundary between Middle Pleniglacial brown soil complexes and the base of the Upper Pleniglacial typical loess cover. Consequently, it represents a major stratigraphic marker for correlations in Western Europe. According to recent OSL dating results, the first thick typical loess unit of the Upper Pleniglacial, covering the main ice-wedge cast horizon, has been deposited shortly after GIS-5 interstadial and could be contemporaneous of H3 event in deep-sea cores. In addition, it is shown that all the large ice wedge casts are developed from the surface of a tundra gley horizon (0.3 to 0.5 m in thickness). As it has been previously demonstrated that tundra gley layers were mainly formed during short interstadial events (malacology, sedimentology), a model linking tundra gley horizons, and ice wedges network regarding to DO stadial-interstadial cycles during the last glacial is proposed. |
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