Fjords as temporary sediment traps: History of glacial erosion and deposition in Muir Inlet, Glacier Bay National Park, southeastern Alaska

Cowan, Ellen A.; Seramur, Keith C.; Powell, Ross D.; Willems, B. A.; Gulick, Sean P. S.; Jaeger, John

doi:10.1130/b26595.1

Cited by 42 publications

(62 citation statements)

References 43 publications

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“…During Columbia Glacier's 30 a rapid retreat, the sediment flux from the glacier averaged at least 1.1 ± 0.3 × 10 7 m 3 a −1 , which is the same order of magnitude as the sediment fluxes estimated from other major temperate Alaskan glaciers (e.g. Hallet and others, 1996;Hunter and others, 1996;Seramur and others, 1997;Cowan and others, 2010). At the broadest temporal scale, the constraints on the sediment flux provided by the terminus positions and the bathymetric measurements suggest that the glacier delivered approximately five times more sediment to the fjord during the 1998-2011 period than in the 1980-1997 period.…”

Section: Implications For the Formation And Evolution Of Fjord Sedimementioning

confidence: 55%

“…The filling of about three quarters of the outer basin long after the glacier had retreated across this area, challenges the common assumption that sediment derived from a glacier only fills the most proximal basin (e.g. Cowan and Powell, 1991;Cowan and others, 2010), and suggests that sediment is transported efficiently throughout the fjord, including passing over significant sills (exceeding tens of meters in height). Fig.…”

Section: Implications For the Formation And Evolution Of Fjord Sedimementioning

confidence: 98%

“…Syvitski, 1989;Koppes and Hallet, 2002;Berger and others, 2008;Cowan and others, 2010;Willems and others, 2011). Our ability to interpret past Earth conditions from these sediment records relies on reliably connecting fjord sediment deposits to the glacial and climatic conditions under which they formed, and to changes in these conditions.…”

Section: Introductionmentioning

confidence: 96%

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Observations and modeling of fjord sedimentation during the 30 year retreat of Columbia Glacier, AK

et al. 2016

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ABSTRACT. To explore links between glacier dynamics, sediment yields and the accumulation of glacial sediments in a temperate setting, we use extensive glaciological observations for Columbia Glacier, Alaska, and new oceanographic data from the fjord exposed during its retreat. High-resolution seismic data indicate that 3.2 × 10 8 m 3 of sediment has accumulated in Columbia Fjord over the past three decades, which corresponds to ∼5 mm a −1 of erosion averaged over the glaciated area. We develop a general model to infer the sediment-flux history from the glacier that is compatible with the observed retreat history, and the thickness and architecture of the fjord sediment deposits. Results reveal a fivefold increase in sediment flux from 1997 to 2000, which is not correlated with concurrent changes in ice flux or retreat rate. We suggest the flux increase resulted from an increase in the sediment transport capacity of the subglacial hydraulic system due to the retreat-related steepening of the glacier surface over a known subglacial deep basin. Because variations in subglacial sediment storage can impact glacial sediment flux, in addition to changes in climate, erosion rate and glacier dynamics, the interpretation of climatic changes based on the sediment record is more complex than generally assumed.

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Section: Implications For the Formation And Evolution Of Fjord Sedimementioning

confidence: 55%

Section: Implications For the Formation And Evolution Of Fjord Sedimementioning

confidence: 98%

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Observations and modeling of fjord sedimentation during the 30 year retreat of Columbia Glacier, AK

et al. 2016

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“…11a). In the relatively mild settings of, for example, SE Alaskan, British Columbian and Patagonian fjords, where much sediment is delivered through annual ice-and snow-melt and sedimentation rates are high at centimetres or more per year (Powell & Molnia 1989;Seramur et al 1997;Cowan et al 2010), turbidity currents are often activated by strong spring runoff, high sediment loads and deltafront failure (e.g. Hughes Clark 2016).…”

Section: Other Submarine Landforms On High-latitude Marginsmentioning

confidence: 99%

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

Dowdeswell

Canals

Jakobsson

et al. 2016

Memoirs

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Glacimarine processes affect about 20% of the global ocean today, and this area expanded considerably under cyclical full-glacial conditions during the Quaternary (Fig. 1) . Many of the submarine landforms produced at the base and margin of past ice sheets remain well preserved on the seafloor in fjords and on high-latitude continental shelves after the retreat of the ice that produced them. These glacial landforms, protected from subaerial erosion and beneath wave-base and tidal currents in water that is often hundreds of metres deep, are gradually buried by both hemipelagic and glacimarine sedimentation; they may be preserved over long periods in the geological record if palaeocontinental shelves are not reworked by subsequent glacier advances or bottom currents ). This means that, first, submarine glacial landforms can be observed at or close to the modern seafloor after retreat of the last great ice sheets from their most recent Quaternary maximum about 18-20 000 years ago using swath-bathymetric mapping systems and, secondly, buried glacial landforms may also be identified and examined within glacial-sedimentary sequences from Quaternary and earlier ice ages using seismic-reflection methods.The development of multibeam echo sounding over the past two decades, coupled with high-accuracy GPS positioning, has allowed morphological mapping of the seafloor at an unprecedented level of detail. In this paper, the variety of submarine glacial landforms observed in modern, Quaternary and more ancient sediments is described. Landforms produced subglacially, those formed at and beyond marine ice-sheet margins, together with the slope processes and bottom currents likely to result in their reworking, are considered along with the sediment volumes of these landforms and the time they take to develop. This is followed by discussion of the significance of submarine glacial landforms and landform-assemblages for reconstruction of the form and flow of past ice sheets, including the former extent and flow direction of ice sheets, whether they are flowing fast as ice streams or slowly in inter-ice stream areas, the nature and rate of ice-sheet deglaciation, conditions at past ice-sheet beds, and inferences on the characteristics of the basal hydrological system and past climatic conditions.

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“…(Seramur et al, 1997), evacuating ice from Adams Inlet by about 1940 c.e. (Price, 1965), and reaching the upper parts of Muir Inlet by about 1990 (Cowen et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Tree Ring—Dated Glacial History for the First Millennium c.e., Casement Glacier and Adams Inlet, Glacier Bay, Alaska, U.S.A.

Horton

Wiles

Lawson

et al. 2016

Arctic, Antarctic, and Alpine Research

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Fjords as temporary sediment traps: History of glacial erosion and deposition in Muir Inlet, Glacier Bay National Park, southeastern Alaska

Cited by 42 publications

References 43 publications

Observations and modeling of fjord sedimentation during the 30 year retreat of Columbia Glacier, AK

Observations and modeling of fjord sedimentation during the 30 year retreat of Columbia Glacier, AK

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

Tree Ring—Dated Glacial History for the First Millennium c.e., Casement Glacier and Adams Inlet, Glacier Bay, Alaska, U.S.A.

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