DOI: 10.1016/j.quascirev.2013.11.005
Scopus记录号: 2-s2.0-84899972599
论文题名: Glaciotectonic deformation and reinterpretation of the Worth Point stratigraphic sequence: Banks Island, NT, Canada
作者: Vaughan J.M. ; England J.H. ; Evans D.J.A.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2014
卷: 91 起始页码: 124
结束页码: 145
语种: 英语
英文关键词: Canadian Arctic
; Glaciotectonism
; Hill-hole pair
; Ice sheet-permafrost interactions
; Quaternary
Scopus关键词: Deformation
; Glacial geology
; Glaciers
; Landforms
; Mining laws and regulations
; Permafrost
; Sea level
; Sediments
; Stratigraphy
; Canadian Arctic
; Formation and evolutions
; Glaciotectonic deformation
; Glaciotectonism
; Hill-hole pair
; Internal architecture
; Quaternary
; Stratigraphic sequences
; Ice
英文摘要: Hill-hole pairs, comprising an ice-pushed hill and associated source depression, cluster in a belt along the west coast of Banks Island, NT. Ongoing coastal erosion at Worth Point, southwest Banks Island, has exposed a section (6km long and ~30m high) through an ice-pushed hill that was transported~2km from a corresponding source depression to the southeast. The exposed stratigraphic sequence is polydeformed and comprises folded and faulted rafts of Early Cretaceous and Late Tertiary bedrock, a prominent organic raft, Quaternary glacial sediments, and buried glacial ice. Three distinct structural domains can be identified within the stratigraphic sequence that represent proximal to distal deformation in an ice-marginal setting. Complex thrust sequences, interfering fold-sets, brecciated bedrock and widespread shear structures superimposed on this ice-marginally deformed sequence record subsequent deformation in a subglacial shear zone.Analysis of cross-cutting relationships within the stratigraphic sequence combined with OSL dating indicate that the Worth Point hill-hole pair was deformed during two separate glaciotectonic events. Firstly, ice sheet advance constructed the hill-hole pair and glaciotectonized the strata ice-marginally, producing a proximal to distal deformation sequence. A glacioisostatically forced marine transgression resulted in extensive reworking of the strata and the deposition of a glaciomarine diamict. A readvance during this initial stage redeformed the strata in a subglacial shear zone, overprinting complex deformation structures and depositing a glaciotectonite ~20m thick. Outwash channels that incise the subglacially deformed strata record a deglacial marine regression, whereas aggradation of glaciofluvial sand and gravel infilling the channels record a subsequent marine transgression. Secondly, a later, largely non-erosive ice margin overrode Worth Point, deforming only the most surficial units in the section and depositing a capping till.The investigation of the Worth Point stratigraphic sequence provides the first detailed description of the internal architecture of a polydeformed hill-hole pair, and as such provides an insight into the formation and evolution of an enigmatic landform. Notably, the stratigraphic sequence documents ice-marginal and subglacial glaciotectonics in permafrost terrain, as well as regional glacial and relative sea level histories. The reinterpreted stratigraphy fundamentally rejects the long-established paleoenvironmental history of Worth Point that assumed a simple 'layer-cake' stratigraphy including the type-site for an organically rich, preglacial interval (Worth Point Fm). © 2013 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60324
Appears in Collections: 过去全球变化的重建
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作者单位: University of Alberta, Edmonton, AB T6G 2R3, Canada; Durham University, Durham City, County Durham, England DH1 3LE, United Kingdom
Recommended Citation:
Vaughan J.M.,England J.H.,Evans D.J.A.. Glaciotectonic deformation and reinterpretation of the Worth Point stratigraphic sequence: Banks Island, NT, Canada[J]. Quaternary Science Reviews,2014-01-01,91