Ice Dynamics and Thermal Regime of Taylor Glacier, South Victoria Land, Antarctica

Robinson, P. H.

doi:10.3189/s0022143000005888

Cited by 33 publications

(62 citation statements)

References 17 publications

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“…If this low exposure age is typical of debris carried by the glacier, then 3 He production during glacial transport is minimal relative to the ages of the moraines in Arena Valley. This seems reasonable because current Taylor Glacier velocities are on the order of 1-15 m yr-' (Robinson, 1984) and cliffs surrounding Finger Mountain (at maximum -10 km away) probably supply most of the debris deposited in Arena Valley (Fig. 1), which suggests a maximum 10,000-yr travel time.…”

Section: Exposure Ages and Age Distributionmentioning

confidence: 99%

“…Prior exposure to cosmic rays is a more difficult issue to resolve. Most of the debris carried by Taylor Glacier probably originally fell on the surface of the glacier from surrounding cliffs; the glacier, at least now, is cold-based west of Arena Valley (Robinson, 1984) and presumably does not incorporate much bedrock debris into basal layers. A sandstone sample collected from the surface of the glacier near the mouth of Arena Valley had an exposure age of 9000 t 3000 yr (Table 1, sample KBA89-91).…”

Section: Exposure Ages and Age Distributionmentioning

confidence: 99%

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Surface exposure geochronology using cosmogenic nuclides : applications in Antarctic glacial geology

Brook¹

1993

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Cosmogenic 3 He, 2 6 A1, and 10 Be have been measured in a variety of Antarctic glacial deposits in the McMurdo Sound-Dry Valleys region. The goals of this project were to provide age constraints for Antarctic glacial events, to investigate production mechanisms of 3 He, 10Be, and 2 6 A1 in terrestrial rocks, to constrain the importance of loss of 3 He from quartz due to diffusion, and to refine methods of exposure-age dating.Moraines deposited in Arena Valley by the Taylor Glacier, an outlet glacier of the East Antarctic Ice Sheet, have exposure ages from -120 kyr to 2 myr. 1 0 Be and 3 He ages of 122 + 29 and 134 ± 54 kyr, respectively, for the Taylor II moraine are consistent with deposition during isotope stage 5e (-120 kyr) and with aerial expansions of the East Antarctic Ice Sheet during interglacial periods. Mean 1 0 Be exposure ages for older moraines in the valley are 362 + 26 kyr (Taylor III), 1.1 ± 0.1 myr (Taylor IVa) and 1.9 ± 0.1 myr (Taylor IVb). Because these older moraines were deposited at most -200 m above the Taylor II limit their ages suggest that major ice sheet advances during the last 2 myr have been broadly similar in magnitude to changes during the last glacial-interglacial cycle. 10 Be ages for stratigraphically older drift deposited by the Taylor Glacier allow extension of this conclusion to -3 myr.1 0 Be measurements in high altitude, pre-Pleistocene glacial deposits in the Dry Valleys preclude rapid uplift of the Transantarctic Mountains (400-1000 m/myr) suggested by controversial biostratigraphic studies of Sirius Group tills. Comparison of measured 10Be concentrations in Sirius Group deposits with those predicted with a model of the effects of uplift on 1 0 Be production suggests minimal uplift of the Transantarctic Mountains over the last 3 myr.3 He, 1 0 Be and 2 6 A1 ages for the "late Wisconsin" Ross Sea Drift, a glacial drift deposited on the coast of McMurdo Sound by the Ross Sea Ice Sheet, range from 8-106 kyr. The age range suggests that this deposit does not, as previous studies suggested, represent a single ice advance in response to lowered sea level at the last glacial maximum. The age range may reflect several ice sheet advances during the last glacial period.Paired measurements of 3 He and 1 0 Be in a number of quartz sandstones from the Dry Valleys region show that cosmogenic 3 He is not completely retained on time scales of greater than 200 kyr. The 3 He and 1 0 Be data, combined with measurements of 3 He concentrations in quartz as a function of grain size, suggest effective 3 He diffusion coefficients in quartz from ~10 -19 to 10-17 cm 2 s -1. These values are one to three orders of magnitude greater than previous experimental determinations extrapolated to low temperature. The data also suggest that 3 He diffusion rates in quartz do not follow simple volume diffusion trends and are probably sample dependent.Crushing quartz grains in vacuo releases variable concentrations of 3 He and 4 He and releases helium with surprisingly high isotopic compositions, u...

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Section: Exposure Ages and Age Distributionmentioning

confidence: 99%

Section: Exposure Ages and Age Distributionmentioning

confidence: 99%

Surface exposure geochronology using cosmogenic nuclides : applications in Antarctic glacial geology

Brook¹

1993

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“…Excavations at the ice edge have revealed that the margin of the ice cap is frozen to the underlying block field and that no debris is entrained in the basal ice layers (Whalley and others, 1981). Estimates of basal ice temperatures using a simple column model (Budd and others, 1971) for the accumulation area and a modification of the Robin model for the ablation area (Robinson, 1984) suggest that the entire ice cap is cold-based. In summer, permafrost exists at a depth of 0.6--{).7 m beneath the surface of nearby ice-free block fields.…”

Section: Study Areamentioning

confidence: 99%

δD-δ¹⁸O Relationships and the Thermal History of Basal Ice Near the margins of two Glaciers in Lyngen, North Norway

et al. 1988

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ABSTRACT. When plotted on a SD-SISO diagram, the isotope values of basal ice formed by refreezing of melt water beneath the cold-based margin of a corrie glacier lie on a straight line with a slope of 5.5. This freezing slope differs from a slope of 7.2 for the basal ice layer of the cold-based ice cap, Balgesvarri, which has not undergone refreezing. The latter slope is similar to that of 7.7 for the local precipitation . Co-isotope measurements from the two glaciers support the associatIOn of subglacial debris entrainment with refreezing processes.

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“…In the Antarctic, because most confluence areas are well above the equilibrium line (although we note that ablation does occur; for example on Taylor Glacier where the maximum ablation is estimated to be −0.44 ma −1 w.e. at the snout; Robinson, 1984), the surface topography is not affected by differential ablation so these features can persist for many tens of kilometres downice. Examples of confluence areas where this process can be expected to operate are regions downstream of nunataks and smaller tributaries feeding sideways into fast-flowing ice streams.…”

Section: Discussionmentioning

confidence: 99%

Longitudinal surface structures (flowstripes) on Antarctic glaciers

Glasser

Gudmundsson

2012

The Cryosphere

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Abstract. Longitudinal surface structures ("flowstripes") are common on many glaciers but their origin and significance are poorly understood. In this paper we present observations of the development of these longitudinal structures from four different Antarctic glacier systems; the Lambert Glacier/Amery Ice Shelf area, the Taylor and Ferrar Glaciers in the Ross Sea sector, Crane and Jorum Glaciers (ice-shelf tributary glaciers) on the Antarctic Peninsula, and the onset zone of a tributary to the Recovery Glacier Ice Stream in the Filchner Ice Shelf area. Mapping from optical satellite images demonstrates that longitudinal surface structures develop in two main situations: (1) as relatively wide flow stripes within glacier flow units and (2) as relatively narrow flow stripes where there is convergent flow around nunataks or at glacier confluence zones. Our observations indicate that the confluence features are narrower, sharper, and more clearly defined features. They are characterised by linear troughs or depressions on the ice surface and are much more common than the former type. Longitudinal surface structures within glacier flow units have previously been explained as the surface expression of localised bed perturbations but a universal explanation for those forming at glacier confluences is lacking. Here we propose that these features are formed at zones of ice acceleration and extensional flow at glacier confluences. We provide a schematic model for the development of longitudinal surface structures based on extensional flow that can explain their ridge and trough morphology as well as their down-ice persistence.

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Ice Dynamics and Thermal Regime of Taylor Glacier, South Victoria Land, Antarctica

Cited by 33 publications

References 17 publications

Surface exposure geochronology using cosmogenic nuclides : applications in Antarctic glacial geology

Surface exposure geochronology using cosmogenic nuclides : applications in Antarctic glacial geology

δD-δ¹⁸O Relationships and the Thermal History of Basal Ice Near the margins of two Glaciers in Lyngen, North Norway

Longitudinal surface structures (flowstripes) on Antarctic glaciers

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Ice Dynamics and Thermal Regime of Taylor Glacier, South Victoria Land, Antarctica

Cited by 33 publications

References 17 publications

Surface exposure geochronology using cosmogenic nuclides : applications in Antarctic glacial geology

Surface exposure geochronology using cosmogenic nuclides : applications in Antarctic glacial geology

δD-δ18O Relationships and the Thermal History of Basal Ice Near the margins of two Glaciers in Lyngen, North Norway

Longitudinal surface structures (flowstripes) on Antarctic glaciers

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Product

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δD-δ¹⁸O Relationships and the Thermal History of Basal Ice Near the margins of two Glaciers in Lyngen, North Norway