DOI: 10.1016/j.quascirev.2018.03.013
Scopus记录号: 2-s2.0-85049047452
论文题名: Reconciling records of ice streaming and ice margin retreat to produce a palaeogeographic reconstruction of the deglaciation of the Laurentide Ice Sheet
作者: Margold M. ; Stokes C.R. ; Clark C.D.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2018
卷: 189 起始页码: 1
结束页码: 30
语种: 英语
英文关键词: Deglaciation
; Geomorphology
; Glacial
; Glaciation
; Ice stream
; Last Glacial Maximum
; Late Glacial
; Laurentide Ice Sheet
; North America
; Pleistocene
Scopus关键词: Drainage
; Flotation
; Geomorphology
; Glacial geology
; Glaciers
; Deglaciations
; Glacial
; Glaciation
; Ice streams
; Last Glacial Maximum
; Late Glacial
; Laurentide ice sheets
; North America
; Pleistocene
; Ice
; deglaciation
; drainage network
; geomorphology
; ice flow
; ice margin
; ice sheet
; ice stream
; Last Glacial Maximum
; Laurentide Ice Sheet
; marine environment
; mass balance
; meltwater
; paleogeography
; Pleistocene
; spatiotemporal analysis
; Younger Dryas
; Arctic Ocean
; Atlantic Coast [Canada]
; Atlantic Coast [North America]
; Baffin Bay [Arctic Ocean]
; Beaufort Sea
; Canada
; Canadian Shield
; Hudson Bay
; North America
英文摘要: This paper reconstructs the deglaciation of the Laurentide Ice Sheet (LIS; including the Innuitian Ice Sheet) from the Last Glacial Maximum (LGM), with a particular focus on the spatial and temporal variations in ice streaming and the associated changes in flow patterns and ice divides. We build on a recent inventory of Laurentide ice streams and use an existing ice margin chronology to produce the first detailed transient reconstruction of the ice stream drainage network in the LIS, which we depict in a series of palaeogeographic maps. Results show that the drainage network at the LGM was similar to modern-day Antarctica. The majority of the ice streams were marine terminating and topographically-controlled and many of these continued to function late into the deglaciation, until the ice sheet lost its marine margin. Ice streams with a terrestrial ice margin in the west and south were more transient and ice flow directions changed with the build-up, peak-phase and collapse of the Cordilleran-Laurentide ice saddle. The south-eastern marine margin in Atlantic Canada started to retreat relatively early and some of the ice streams in this region switched off at or shortly after the LGM. In contrast, the ice streams draining towards the north-western and north-eastern marine margins in the Beaufort Sea and in Baffin Bay appear to have remained stable throughout most of the Late Glacial, and some of them continued to function until after the Younger Dryas (YD). The YD influenced the dynamics of the deglaciation, but there remains uncertainty about the response of the ice sheet in several sectors. We tentatively ascribe the switching-on of some major ice streams during this period (e.g. M'Clintock Channel Ice Stream at the north-west margin), but for other large ice streams whose timing partially overlaps with the YD, the drivers are less clear and ice-dynamical processes, rather than effects of climate and surface mass balance are viewed as more likely drivers. Retreat rates markedly increased after the YD and the ice sheet became limited to the Canadian Shield. This hard-bed substrate brought a change in the character of ice streaming, which became less frequent but generated much broader terrestrial ice streams. The final collapse of the ice sheet saw a series of small ephemeral ice streams that resulted from the rapidly changing ice sheet geometry in and around Hudson Bay. Our reconstruction indicates that the LIS underwent a transition from a topographically-controlled ice drainage network at the LGM to an ice drainage network characterised by less frequent, broad ice streams during the later stages of deglaciation. These deglacial ice streams are mostly interpreted as a reaction to localised ice-dynamical forcing (flotation and calving of the ice front in glacial lakes and transgressing sea; basal de-coupling due to large amount of meltwater reaching the bed, debuttressing due to rapid changes in ice sheet geometry) rather than as conveyors of excess mass from the accumulation area of the ice sheet. At an ice sheet scale, the ice stream drainage network became less widespread and less efficient with the decreasing size of the deglaciating ice sheet, the final elimination of which was mostly driven by surface melt. © 2018 The Authors Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/112197
Appears in Collections: 气候减缓与适应
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作者单位: Durham University, Department of Geography, Lower Mountjoy, South Road, Durham, DH1 3LE, United Kingdom; Stockholm University, Department of Physical Geography, Stockholm, 106 91, Sweden; University of Sheffield, Department of Geography, Western Bank, Sheffield, S10 2TN, United Kingdom
Recommended Citation:
Margold M.,Stokes C.R.,Clark C.D.. Reconciling records of ice streaming and ice margin retreat to produce a palaeogeographic reconstruction of the deglaciation of the Laurentide Ice Sheet[J]. Quaternary Science Reviews,2018-01-01,189