DOI: 10.1016/j.palaeo.2012.12.002
论文题名: Subglacial to proglacial depositional environments in an Ordovician glacial tunnel valley, Alnif, Morocco
作者: Clerc S. ; Buoncristiani J.-F. ; Guiraud M. ; Vennin E. ; Desaubliaux G. ; Portier E.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2013
卷: 370 起始页码: 127
结束页码: 144
语种: 英语
英文关键词: Morocco
; Ordovician ice sheet
; Proglacial environment
; Subglacial environment
; Tunnel valley
英文摘要: 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 from subglacial to proglacial environments, and an additional sixth facies association, overtopping the tunnel valley infill, and associated with 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. © 2012 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69858
Appears in Collections: 过去全球变化的重建
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作者单位: Laboratoire Biogeosciences UMR/CNRS 6282 Université de Bourgogne, 6 Bd Gabriel, 21000 DIJON, France; GDF Suez EPI, 1 place Samuel de Champlain, Faubourg de l'Arche 92930 Paris La Défense Cedex, France
Recommended Citation:
Clerc S.,Buoncristiani J.-F.,Guiraud M.,et al. Subglacial to proglacial depositional environments in an Ordovician glacial tunnel valley, Alnif, Morocco[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,370