DOI: 10.1016/j.quascirev.2018.02.013
Scopus记录号: 2-s2.0-85042920208
论文题名: Late-Quaternary glacial to postglacial sedimentation in three adjacent fjord-lakes of the Québec North Shore (eastern Canadian Shield)
作者: Poiré A.G. ; Lajeunesse P. ; Normandeau A. ; Francus P. ; St-Onge G. ; Nzekwe O.P.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2018
卷: 186 起始页码: 91
结束页码: 110
语种: 英语
英文关键词: Acoustic stratigraphy
; Deglaciation
; Fjord-lakes
; Laurentide Ice Sheet
; Swath bathymetry
Scopus关键词: Bathymetry
; Glacial geology
; Glaciers
; Lakes
; Ocean currents
; Sediment transport
; Sediments
; Stratigraphy
; Deglaciations
; Fjord lakes
; Geographical positions
; Laurentide ice sheets
; Sedimentary basin
; Stratigraphic units
; Sub-bottom profiles
; Swath bathymetry
; Ice
; bedrock
; deglaciation
; fjord
; fluvial deposit
; fluvial geomorphology
; glacial rebound
; glacioisostasy
; ice retreat
; imagery
; Laurentide Ice Sheet
; mass movement
; moraine
; paleoenvironment
; Postglacial
; Quaternary
; sedimentary basin
; sedimentation
; stratigraphy
; swath bathymetry
; uplift
; Canada
; Canadian Shield
; Quebec [Canada]
英文摘要: High-resolution swath bathymetry imagery allowed mapping in great detail the sublacustrine geomorphology of lakes Pentecôte, Walker and Pasteur, three deep adjacent fjord-lakes of the Québec North Shore (eastern Canada). These sedimentary basins have been glacio-isostatically uplifted to form deep steep-sided elongated lakes. Their key geographical position and limnogeological characteristics typical of fjords suggest exceptional potential for long-term high-resolution paleoenvironmental reconstitutions. Acoustic subbottom profiles acquired using a bi-frequency Chirp echosounder (3.5 & 12 kHz), together with cm- and m-long sediment core data, reveal the presence of four acoustic stratigraphic units. The acoustic basement (Unit 1) represents the structural bedrock and/or the ice-contact sediments of the Laurentide Ice Sheet and reveals V-shaped bedrock valleys at the bottom of the lakes occupied by ice-loaded sediments in a basin-fill geometry (Unit 2). Moraines observed at the bottom of lakes and in their structural valleys indicate a deglaciation punctuated by short-term ice margin stabilizations. Following ice retreat and their isolation, the fjord-lakes were filled by a thick draping sequence of rhythmically laminated silts and clays (Unit 3) deposited during glaciomarine and/or glaciolacustrine settings. These sediments were episodically disturbed by mass-movements during deglaciation due to glacial-isostatic rebound. AMS 14C dating reveal that the transition between deglaciation of the lakes Pentecôte and Walker watersheds and the development of para- and post-glacial conditions occurred around 8000 cal BP. The development of the lake-head river delta plain during the Holocene provided a constant source of fluvial sediment supply to the lakes and the formation of turbidity current bedforms on the sublacustrine delta slopes. The upper sediment succession (i.e., ∼4–∼6.5 m) consists of a continuous para-to post-glacial sediment drape (Unit 4) that contains laminated and massive sediment and series of Rapidly Deposited Layers. These results allow establishing a conceptual model of how a glaciated coastal fjord evolves during and after deglaciation in a context of rapid glacio-isostatically induced forced regression. © 2018 Elsevier Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/112245
Appears in Collections: 气候减缓与适应
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作者单位: Département de géographie & Centre d’études nordiques, Université Laval, Québec, QC G1V 0A6, Canada; Geological Survey of Canada (Atlantic), Bedford Institute of Oceanography, Dartmouth, NS B2Y 4A2, Canada; Centre Eau Terre Environnement, Institut National de la Recherche Scientifique and GEOTOP, Québec, QC G1K 9A9, Canada; Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski and GEOTOP, Rimouski, QC G5L 2Z9, Canada
Recommended Citation:
Poiré A.G.,Lajeunesse P.,Normandeau A.,et al. Late-Quaternary glacial to postglacial sedimentation in three adjacent fjord-lakes of the Québec North Shore (eastern Canadian Shield)[J]. Quaternary Science Reviews,2018-01-01,186