Variable history of Quaternary ice-sheet advance across the Beaufort Sea margin, Arctic Ocean

Batchelor, Christine; Dowdeswell, Julian A.; Pietras, Jeffrey T.

doi:10.1130/g33669.1

Cited by 26 publications

(12 citation statements)

References 11 publications

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“…In contrast, the Amundsen Gulf Ice Stream is thought to have operated throughout deglaciation, and was spatially more stable than both the M'Clure Strait Ice Stream to the north and the Mackenzie Trough Ice Stream to the west Brown, 2012). It is evidenced both by terrestrial landform record on the mainland and on Victoria Island (Sharpe, 1988;Stokes et al, 2006;Kleman and Glasser, 2007;Storrar and Stokes, 2007;Stokes et al, 2009;Brown et al, 2011;Brown, 2012), and by erosion and distinctly streamlined morphology of the seabed in Amundsen Gulf (Supplementary data; Batchelor et al, 2013b).…”

Section: Canadian Arctic Archipelagomentioning

confidence: 86%

Ice streams in the Laurentide Ice Sheet: Identification, characteristics and comparison to modern ice sheets

Margold

Stokes

Clark

2015

Earth-Science Reviews

211

222

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This paper presents a comprehensive review and synthesis of ice streams in the Laurentide Ice Sheet (LIS) based on a new mapping inventory that includes previously hypothesised ice streams and includes a concerted effort to search for others from across the entire ice sheet bed. The inventory includes 117 ice streams, which have been identified based on a variety of evidence including their bedform imprint, large-scale geomorphology/ topography, till properties, and ice rafted debris in ocean sediment records. Despite uncertainty in identifying ice streams in hard bedrock areas, it is unlikely that any major ice streams have been missed. During the Last Glacial Maximum, Laurentide ice streams formed a drainage pattern that bears close resemblance to the present day velocity patterns in modern ice sheets. Large ice streams had extensive onset zones and were fed by multiple tributaries and, where ice drained through regions of high relief, the spacing of ice streams shows a degree of spatial self-organisation which has hitherto not been recognised. Topography exerted a primary control on the location of ice streams, but there were large areas along the western and southern margin of the ice sheet where the bed was composed of weaker sedimentary bedrock, and where networks of ice streams switched direction repeatedly and probably over short time scales. As the ice sheet retreated onto its low relief interior, several ice streams show no correspondence with topography or underlying geology, perhaps facilitated by localised build-up of pressurised subglacial meltwater. They differed from most other ice stream tracks in having much lower length-to-width ratios and have no modern analogues. There have been very few attempts to date the initiation and cessation of ice streams, but it is clear that ice streams switched on and off during deglaciation, rather than maintaining the same trajectory as the ice margin retreated. We provide a first order estimate of changes in ice stream activity during deglaciation and show that around 30% of the margin was drained by ice streams at the LGM (similar to that for present day Antarctic ice sheets), but this decreases to 15% and 12% at 12 cal ka BP and 10 cal ka BP, respectively. The extent to which these changes in the ice stream drainage network represent a simple and predictable readjustment to a changing mass balance driven by climate, or internal ice dynamical feedbacks unrelated to climate (or both) is largely unknown and represents a key area for future work to address.

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Section: Canadian Arctic Archipelagomentioning

confidence: 86%

Ice streams in the Laurentide Ice Sheet: Identification, characteristics and comparison to modern ice sheets

Margold

Stokes

Clark

2015

Earth-Science Reviews

211

222

View full text Add to dashboard Cite

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“…The Amundsen Gulf and M'Clure Strait ice-streams were fed by major drainage basins of the Laurentide Ice Sheet, and they supplied significant quantities of ice and sediment to the Arctic Ocean during much of the Quaternary. In contrast, there is evidence for only two Quaternary ice-stream advances through the Mackenzie Trough which was situated at the extreme northwest ice-sheet margin and was likely fed by a smaller drainage basin (Batchelor et al 2013).…”

Section: Initial Velocity Vmentioning

confidence: 90%

“…These observations are consistent with the variable history of Laurentide Ice Sheet advance across the Beaufort-Mackenzie and Banks Islands margins. Batchelor et al (2013Batchelor et al ( , 2014 provide seismic stratigraphic evidence for at least eight Quaternary ice-stream advances through the Amundsen Gulf Trough to the shelf break, where a trough-mouth fan with a minimum volume of 10 000 km 3 is present on the adjacent slope. A similar history of ice-stream advance was focussed through the M'Clure Strait Trough, resulting in deposition of an even larger trough-mouth fan of about 60 000 km 3 (Batchelor et al 2014).…”

Section: Initial Velocity Vmentioning

confidence: 99%

Seismic velocities within the sedimentary succession of the Canada Basin and southern Alpha-Mendeleev Ridge, Arctic Ocean: evidence for accelerated porosity reduction?

Shimeld¹,

Li²,

Chian³

et al. 2015

Geophysical Journal International

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S U M M A R YThe Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity-depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km 2 . The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity-depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity-depth profiles for each seismic trace. A thickness of 12-13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity-depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares favourably with borehole data for Miocene turbidites in the eastern Gulf of Mexico. The station-specific results also indicate that Quaternary sediments coarsen towards the Beaufort-Mackenzie and Banks Island margins in a manner that is consistent with the variable history of Laurentide Ice Sheet advance documented for these margins. Lithological factors do not fully account for the elevated velocity-depth trends that are associated with the southwestern Canada Basin and the Alpha-Mendeleev magnetic domain. Accelerated porosity reduction due to elevated palaeo-heat flow is inferred for these regions, which may be related to the underlying crustal types or possibly volcanic

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“…To determine the seismic facies that exist in our data set, we first identify packages between the glacial erosion surfaces that display different acoustic properties as has been done in previous studies [ Carlson , ; Sexton et al ., ; Cai et al ., ; Powell and Cooper , ; Batchelor et al ., ]. By examining the continuity and brightness of seismic reflectors within these packages, we were able to identify five distinct seismic facies: Cs, Dl, Ch, Dh, and Cl.…”

Section: Methodsmentioning

confidence: 98%

Imaging evidence for Hubbard Glacier advances and retreats since the last glacial maximum in Yakutat and Disenchantment Bays, Alaska

Zurbuchen

Gulick

Walton

et al. 2015

Geochem Geophys Geosyst

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High-resolution 2-D multichannel seismic data, collected during the 2012 UTIG-USGS National Earthquake Hazards Reduction Program survey of Disenchantment and Yakutat Bays in southeast Alaska, provide insight into their glacial history. These data show evidence of two unconformities, appearing in the form of channels, and are interpreted to be advance pathways for Hubbard Glacier. The youngest observable channel, thought to have culminated near the main phase of the Little Ice Age (LIA), is imaged in Disenchantment Bay and ends at a terminal moraine near Blizhni Point. An older channel, thought to be from an advance that culminated in the early phase of the LIA, extends from Disenchantment Bay into the northeastern edge of Yakutat Bay, turning southward at Knight Island and terminating on the southeastern edge of Yakutat Bay. Our interpretation is that Hubbard Glacier has repeatedly advanced around the east side of Yakutat Bay in Knight Island Channel, possibly due to the presence of Malaspina Glacier cutting off access to central Yakutat Bay during times of mutual advance. We observe two distinct erosional surfaces and retreat sequences of Hubbard Glacier in Yakutat Bay, supporting the hypothesis that minor glacial advances in fjords do not erode all prior sediment accumulations. Interpretation of chaotic seismic facies between these two unconformities suggests that Hubbard Glacier exhibits rapid retreats and that Disenchantment Bay is subject to numerous episodes of outburst flooding and morainal bank collapse. These findings also suggest that tidewater glaciers preferentially reoccupy the same channels in bay and marine settings during advances.

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Variable history of Quaternary ice-sheet advance across the Beaufort Sea margin, Arctic Ocean

Cited by 26 publications

References 11 publications

Ice streams in the Laurentide Ice Sheet: Identification, characteristics and comparison to modern ice sheets

Ice streams in the Laurentide Ice Sheet: Identification, characteristics and comparison to modern ice sheets

Seismic velocities within the sedimentary succession of the Canada Basin and southern Alpha-Mendeleev Ridge, Arctic Ocean: evidence for accelerated porosity reduction?

Imaging evidence for Hubbard Glacier advances and retreats since the last glacial maximum in Yakutat and Disenchantment Bays, Alaska

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