Subglacial to proglacial depositional environments in an Ordovician glacial tunnel valley, Alnif, Morocco.
18 pages International audience This paper presents the sedimentary analysis of an exceptional Ordovician glacial tunnel valley in the eastern part of the Anti-Atlas. The valley infill comprises two major glacial erosion surfaces (striated pavements) each overlain by a fining-upward glacial unit. Th...
Published in: | Palaeogeography, Palaeoclimatology, Palaeoecology |
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ftunivnantes:oai:HAL:hal-00781624v1 2023-05-15T13:58:19+02:00 Subglacial to proglacial depositional environments in an Ordovician glacial tunnel valley, Alnif, Morocco. Clerc, Sylvain Buoncristiani, Jean-François Guiraud, Michel Vennin, Emmanuelle Desaubliaux, Guy Portier, Eric Biogéosciences UMR 6282 (BGS) Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS) Exploration Production International Gaz de France Suez (GDF Suez) Funding of this study from GDF Suez EPI. 2013-01-15 https://hal.science/hal-00781624 https://doi.org/10.1016/j.palaeo.2012.12.002 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.palaeo.2012.12.002 hal-00781624 https://hal.science/hal-00781624 doi:10.1016/j.palaeo.2012.12.002 ISSN: 0031-0182 Palaeogeography, Palaeoclimatology, Palaeoecology https://hal.science/hal-00781624 Palaeogeography, Palaeoclimatology, Palaeoecology, 2013, 370, pp.127-144. ⟨10.1016/j.palaeo.2012.12.002⟩ Tunnel valley Ordovician ice sheet Subglacial environment Proglacial environment Morocco [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology info:eu-repo/semantics/article Journal articles 2013 ftunivnantes https://doi.org/10.1016/j.palaeo.2012.12.002 2023-02-15T00:24:07Z 18 pages International audience This paper presents the sedimentary analysis of an exceptional Ordovician glacial tunnel valley in the eastern part of the Anti-Atlas. The valley infill comprises two major glacial erosion surfaces (striated pavements) each overlain by a fining-upward glacial unit. These units are composed of five distinct facies associations, recording the evolution fromsubglacial to proglacial environments, and an additional sixth facies association, overtopping the tunnel valley infill, and associatedwith post-glacial environments. The tunnel valley infill also records a transitional environment between the subglacial and proglacial settings, which is compared with the Antarctic ice-sheet margin. These three environments are defined by the position of the grounding line and the coupling line. The new proposed depositional model also differs from usual Ordovician depositional models in which the main tunnel valley infill is interpreted as essentially proglacial outwash deposits, in a range of glaciomarine to glaciofluvial environments. Overall, a substantial part of the valley infill (~50% of volume) was deposited in a subglacial setting. The sedimentary bodies could form potentially thick and laterally extended, although these were limited by the shape and extent of the subglacial accommodation space. Finally, the sedimentary record, when compared with regional analogues, also provides information for the palaeogeographic reconstruction of the Ordovician ice-sheet in this region. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Université de Nantes: HAL-UNIV-NANTES Antarctic The Antarctic Palaeogeography, Palaeoclimatology, Palaeoecology 370 127 144 |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
Tunnel valley Ordovician ice sheet Subglacial environment Proglacial environment Morocco [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology |
spellingShingle |
Tunnel valley Ordovician ice sheet Subglacial environment Proglacial environment Morocco [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology Clerc, Sylvain Buoncristiani, Jean-François Guiraud, Michel Vennin, Emmanuelle Desaubliaux, Guy Portier, Eric Subglacial to proglacial depositional environments in an Ordovician glacial tunnel valley, Alnif, Morocco. |
topic_facet |
Tunnel valley Ordovician ice sheet Subglacial environment Proglacial environment Morocco [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology |
description |
18 pages International audience This paper presents the sedimentary analysis of an exceptional Ordovician glacial tunnel valley in the eastern part of the Anti-Atlas. The valley infill comprises two major glacial erosion surfaces (striated pavements) each overlain by a fining-upward glacial unit. These units are composed of five distinct facies associations, recording the evolution fromsubglacial to proglacial environments, and an additional sixth facies association, overtopping the tunnel valley infill, and associatedwith post-glacial environments. The tunnel valley infill also records a transitional environment between the subglacial and proglacial settings, which is compared with the Antarctic ice-sheet margin. These three environments are defined by the position of the grounding line and the coupling line. The new proposed depositional model also differs from usual Ordovician depositional models in which the main tunnel valley infill is interpreted as essentially proglacial outwash deposits, in a range of glaciomarine to glaciofluvial environments. Overall, a substantial part of the valley infill (~50% of volume) was deposited in a subglacial setting. The sedimentary bodies could form potentially thick and laterally extended, although these were limited by the shape and extent of the subglacial accommodation space. Finally, the sedimentary record, when compared with regional analogues, also provides information for the palaeogeographic reconstruction of the Ordovician ice-sheet in this region. |
author2 |
Biogéosciences UMR 6282 (BGS) Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS) Exploration Production International Gaz de France Suez (GDF Suez) Funding of this study from GDF Suez EPI. |
format |
Article in Journal/Newspaper |
author |
Clerc, Sylvain Buoncristiani, Jean-François Guiraud, Michel Vennin, Emmanuelle Desaubliaux, Guy Portier, Eric |
author_facet |
Clerc, Sylvain Buoncristiani, Jean-François Guiraud, Michel Vennin, Emmanuelle Desaubliaux, Guy Portier, Eric |
author_sort |
Clerc, Sylvain |
title |
Subglacial to proglacial depositional environments in an Ordovician glacial tunnel valley, Alnif, Morocco. |
title_short |
Subglacial to proglacial depositional environments in an Ordovician glacial tunnel valley, Alnif, Morocco. |
title_full |
Subglacial to proglacial depositional environments in an Ordovician glacial tunnel valley, Alnif, Morocco. |
title_fullStr |
Subglacial to proglacial depositional environments in an Ordovician glacial tunnel valley, Alnif, Morocco. |
title_full_unstemmed |
Subglacial to proglacial depositional environments in an Ordovician glacial tunnel valley, Alnif, Morocco. |
title_sort |
subglacial to proglacial depositional environments in an ordovician glacial tunnel valley, alnif, morocco. |
publisher |
HAL CCSD |
publishDate |
2013 |
url |
https://hal.science/hal-00781624 https://doi.org/10.1016/j.palaeo.2012.12.002 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_source |
ISSN: 0031-0182 Palaeogeography, Palaeoclimatology, Palaeoecology https://hal.science/hal-00781624 Palaeogeography, Palaeoclimatology, Palaeoecology, 2013, 370, pp.127-144. ⟨10.1016/j.palaeo.2012.12.002⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.palaeo.2012.12.002 hal-00781624 https://hal.science/hal-00781624 doi:10.1016/j.palaeo.2012.12.002 |
op_doi |
https://doi.org/10.1016/j.palaeo.2012.12.002 |
container_title |
Palaeogeography, Palaeoclimatology, Palaeoecology |
container_volume |
370 |
container_start_page |
127 |
op_container_end_page |
144 |
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1766266546473140224 |