DOI: 10.1016/j.quascirev.2014.03.011
Scopus记录号: 2-s2.0-84899907299
论文题名: Quaternary geology of the Duck Hawk Bluffs, southwest Banks Island, Arctic Canada: A re-investigation of a critical terrestrial type locality for glacial and interglacial events bordering the Arctic Ocean
作者: Evans D.J.A. ; England J.H. ; La Farge C. ; Coulthard R.D. ; Lakeman T.R. ; Vaughan J.M.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2014
卷: 91 起始页码: 82
结束页码: 123
语种: 英语
英文关键词: Banks Island
; Canadian Arctic glaciations and interglacials
; Duck Hawk Bluffs
; Glacitectonics
; Palaeoenvironments
; Quaternary stratigraphy
Scopus关键词: Glacial geology
; Minerals
; Mining laws and regulations
; Sedimentation
; Sediments
; Stratigraphy
; Banks Island
; Duck Hawk Bluffs
; Glacitectonics
; Interglacials
; Palaeoenvironments
; Quaternary stratigraphies
; Ice
; Bryophyta
; bryophytes
英文摘要: Duck Hawk Bluffs, southwest Banks Island, is a primary section (8km long and 60m high) in the western Canadian Arctic Archipelago exposing a long record of Quaternary sedimentation adjacent to the Arctic Ocean. A reinvestigation of Duck Hawk Bluffs demonstrates that it is a previously unrecognized thrust-block moraine emplaced from the northeast by Laurentide ice. Previous stratigraphic models of Duck Hawk Bluffs reported a basal unit of preglacial fluvial sand and gravel (Beaufort Fm, forested Arctic), overlain by a succession of three glaciations and at least two interglacials. Our observations dismiss the occurrence of preglacial sediments and amalgamate the entire record into three glacial intervals and one prominent interglacial. The first glacigenic sedimentation is recorded by an ice-contact sandur containing redeposited allochthonous organics previously assigned to the Beaufort Fm. This is overlain by fine-grained sediments with ice wedge pseudomorphs and well-preserved bryophyte assemblages corresponding to an interglacial environment similar to modern. The second glacial interval is recorded by ice-proximal mass flows and marine rhythmites that were glacitectonized when Laurentide ice overrode the site from Amundsen Gulf to the south. Sediments of this interval have been reported to be magnetically reversed (>780ka). The third interval of glacigenic sedimentation includes glacifluvial sand and gravel recording the arrival of Laurentide ice that overrode the site from the northeast (island interior) depositing a glacitectonite and constructing the thrust block moraine that comprises Duck Hawk Bluffs. Sediments of this interval have been reported to be magnetically normal (<780ka). The glacitectonite contains a highly deformed melange of pre-existing sediments that were previously assigned to several formally named, marine and interglacial deposits resting in an undeformed sequence. In contrast, the tectonism associated with the thrust block moraine imparted pervasive deformation throughout all underlying units, highlighted by a previously unrecognized raft of Cretaceous bedrock. During this advance, Laurentide ice from the interior of Banks Island coalesced with an ice stream in Amundsen Gulf, depositing the interlobate Sachs Moraine that contains shells as young as ~24calkaBP (Late Wisconsinan). During deglaciation, meltwater emanating from these separating ice lobes deposited outwash that extended to deglacial marine limit (11masl) along the west coast of Banks Island. Our new stratigraphic synthesis fundamentally revises and simplifies the record of past Quaternary environments preserved on southwest Banks Island, which serves as a key terrestrial archive for palaeoenvironmental change. © 2014 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60323
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Geography, Durham University, South Road, Durham DH1 3LE, United Kingdom; Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB T6G 2E3, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada; Department of Earth Sciences, Dalhousie University, Halifax, NS B3H 4R2, Canada
Recommended Citation:
Evans D.J.A.,England J.H.,La Farge C.,et al. Quaternary geology of the Duck Hawk Bluffs, southwest Banks Island, Arctic Canada: A re-investigation of a critical terrestrial type locality for glacial and interglacial events bordering the Arctic Ocean[J]. Quaternary Science Reviews,2014-01-01,91