Glacial geology and origin of fossiliferous-erratic-bearing moraines, southern McMurdo Sound, Antarctica- an alternative ice sheet hypothesis

2000 ◽  
pp. 19-37 ◽  
Author(s):  
Gary S. Wilson
Keyword(s):  
Ice Sheet ◽  
Glacial Geology ◽  
Mcmurdo Sound

scholarly journals Dynamic, in situ measurement of sea-ice characteristic length

2001 ◽  
Vol 33 ◽  
pp. 339-344 ◽  
Author(s):  
Colin Fox ◽  
Tim G. Haskell ◽  
Hyuck Chung
Keyword(s):  
Sea Ice ◽  
Characteristic Length ◽  
Ice Sheet ◽  
In Situ Measurement ◽  
Effective Characteristic ◽  
Mcmurdo Sound ◽  
Periodic Loading ◽  
Flexural Response ◽  
Measurement Signal

AbstractWe present a method for measuring the characteristic length of sea ice based on fitting to a recently found solution for the flexural response of a floating ice sheet subject to localized periodic loading. Unlike previous techniques, the method enables localized measurements at single frequencies of geophysical interest, and since the measurements may be synchronously demodulated, gives excellent rejection of unwanted measurement signal (e.g. from ocean swell). The loading mechanism is described and we discuss how the effective characteristic length may be determined using a range of localized measurements. The method is used to determine the characteristic length of the sea ice in McMurdo Sound, Antarctica.

II.—The Scandinavian Ice-Sheet and the Baltic Glacier: a Sceptical Commentary

1899 ◽  
Vol 6 (1) ◽  
pp. 4-13
Author(s):  
Henry H. Howorth
Keyword(s):  
Ice Sheet ◽  
Northern Europe ◽  
Glacial Geology ◽  
Scandinavian Ice Sheet ◽  
The Baltic ◽  
Great Focus ◽  
Geological Magazine

If the paper on the recent geology of Sweden which has already appeared in the GEOLOGICAL MAGAZINE is sound in argument (and I have not met anyone yet who has answered it), it follows that the views ordinarily current in regard to the glacial geology of Northern Europe will have to be greatly modified. Scandinavia is confessedly the great focus and centre of the phenomena which have been interpreted as glacial.

The local Last Glacial Maximum in McMurdo Sound, Antarctica: Implications for ice-sheet behavior in the Ross Sea Embayment

2019 ◽  
Vol 132 (1-2) ◽  
pp. 31-47 ◽  
Author(s):  
Andrew J. Christ ◽  
Paul R. Bierman
Keyword(s):  
Last Glacial Maximum ◽  
Ross Sea ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Significant Advance ◽  
Ice Flow ◽  
Mcmurdo Sound ◽  
Last Glacial ◽  
Transantarctic Mountains ◽  
Western Ross Sea

AbstractDuring the Last Glacial Maximum (LGM), a grounded ice sheet filled the Ross Sea Embayment in Antarctica and deposited glacial sediments on volcanic islands and peninsulas in McMurdo Sound and coastal regions of the Transantarctic Mountains. The flow geometry and retreat history of this ice are debated, with contrasting views yielding divergent implications for the interaction between and stability of the East and West Antarctic ice sheets during late Quaternary time. Here, we present terrestrial geomorphologic evidence and reconstruct former ice-marginal environments, ice sheet elevations, and ice-flow directions in McMurdo Sound. Fossil algae in ice-marginal sediments provide a coherent radiocarbon chronology of maximum ice extent and deglaciation. We integrate these data with marine records to reconstruct grounded ice dynamics in McMurdo Sound and the western Ross Sea. The combined data set suggests ice flow toward the Transantarctic Mountains in McMurdo Sound during peak glaciation, with thick, grounded ice at or near its maximum position between 19.6 and 12.3 ka. Persistent grounded ice in McMurdo Sound and across the western Ross Sea after Meltwater Pulse 1a (14.0–14.5 ka) suggests that this sector of Antarctica did not significantly contribute to this rapid sea-level rise event. Our data show no significant advance of locally derived ice from the Transantarctic Mountains into McMurdo Sound during the local LGM.

The glacial geology of northeastern Ellesmere Island, N.W.T., Canada

1978 ◽  
Vol 15 (4) ◽  
pp. 603-617 ◽  
Author(s):  
John England
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ellesmere Island ◽  
Glacial Geology ◽  
Radiocarbon Dates ◽  
Previous Evidence ◽  
Marine Deposits ◽  
Last Glaciation ◽  
Distal Side ◽  
Stratigraphic Boundary

Thirty-five radiocarbon dates associated with former ice sheet margins and raised marine deposits are presented from northeastern Ellesmere Island. Along the southern margin of Hazen Plateau, and in inner Archer Fiord, a prominent morpho-stratigraphic boundary is marked by the Hazen Moraines. These moraines represent a restricted ice advance during the last glaciation and date ca. 8130 ± 200 BP. On the immediate distal side of the Hazen Moraines, eastward for 100 km towards northwestern Greenland, the majority of dates on marine limits show synchronous emergence beginning ca. 7500 BP. This zone of synchronous emergence is considered to represent an ice-free corridor isostatically unloaded between the margins of the receding Greenland and Ellesmere island ice sheets.A more widespread till, above and beyond the Hazen Moraines, extends out of Archer Fiord–Lady Franklin Bay to Robeson and Kennedy channels. This maximum ice advance is considered to predate the last glaciation on the basis of 14C and amino acid dates from ice-marginal deposits; however, alternative interpretations of the data are presented. Previous evidence suggesting an older advance of the Greenland Ice Sheet onto this coastline is confirmed. Several glaciers in the area are presently at their maximum postglacial positions.

Reconciling marine and terrestrial evidence for post LGM ice sheet retreat in southern McMurdo Sound, Antarctica

2017 ◽  
Vol 157 ◽  
pp. 1-13 ◽  
Author(s):  
Jacob T.H. Anderson ◽  
Gary S. Wilson ◽  
David Fink ◽  
Kat Lilly ◽  
Richard H. Levy ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Mcmurdo Sound

scholarly journals Glacial geology of Saalian relief around Midwolda, eastern Groningen, the Netherlands

2018 ◽  
Vol 97 (4) ◽  
pp. 261-282
Author(s):  
Sjoerd J. Kluiving ◽  
Gerard Aalbersberg ◽  
Ronald T. van Balen ◽  
Cornelis Kasse
Keyword(s):  
Structural Geology ◽  
The Netherlands ◽  
Cross Sections ◽  
Deformation Zone ◽  
Flow Direction ◽  
Ice Sheet ◽  
Lateral Heterogeneity ◽  
Glacial Geology ◽  
Ice Flow ◽  
Gravel Content

AbstractDue to canal-digging activities in 2011 and 2014, two small and one large temporary exposure, all ranging from 4 to 5 m in depth, were studied with respect to the sedimentology and structural geology, in the glacial ridge of Midwolda, Groningen, the Netherlands. The lowermost unit consists of clay of Elsterian age and is composed of glaciolacustrine and turbiditic deposits (Peelo Formation). These show synsedimentary deformations due to loading, as well as post-sedimentary Saalian glaciotectonic deformations, consisting of folding, and faulting structures. The overlying Saalian till sequence consists of two main units. The lower unit, with clear features of a subglacial deformation zone (e.g. lateral heterogeneity), has a local origin and strongly resembles the underlying Elsterian clay. Glacial tectonic and morphological observations indicate a primary NE–SW ice-flow direction. The second till layer has a sandy texture and high crystalline gravel content, while glacial-tectonic indicators point to a NW–SE ice-flow direction. The deformation of the till layers has caused a repetition and mixing of till layers, due to the last ice movement. The NW–SE ice movement is supported by the morphology as well as data from erratic gravel counts. Correlation with geological cross-sections strongly suggests regional subsurface control on ice-sheet behaviour.

scholarly journals The Western Barents Sea and the Svalbard archipelago 18 000 years ago – a finite-difference computer model reconstruction

1992 ◽  
Vol 38 (129) ◽  
pp. 295-301
Author(s):  
Elisabeth Isaksson
Keyword(s):  
Steady State ◽  
Finite Difference ◽  
Computer Model ◽  
Barents Sea ◽  
Ice Sheet ◽  
Precipitation Pattern ◽  
Glacial Geology ◽  
Ice Streams ◽  
Svalbard Archipelago ◽  
Marine Areas

AbstractA finite-difference computer model was used to reconstruct a steady-state ice sheet over the western Barents Sea and the Svalbard archipelago at the last glacial maximum 18 000 BP. Flowlines were reconstructed from the ice margin to the ice dome based on information about glacial geology, bedrock topography, basal thermal regime and the present precipitation pattern. The modelling result suggests a 1700 m high marine ice dome east of Spitsbergen and a 1350 m high terrestrial dome over northwest Spitsbergen. Over most of the terrestrial areas, the bed is frozen while in the marine areas the bed is thawed. This is in agreement with both the terrestrial and the marine glacial geology records. The height of the terrestrial dome implies that the ice sheet was thin and left several of the higher mountain peaks as nunataks. Three major ice streams were reconstructed in the most pronounced over-deepened marine channels. This modelling experiment did not allow any major ice streams in the fjords of Spitsbergen during steady-state conditions.

scholarly journals Late Pleistocene interactions of East and West Antarctic Ice-flow Regimes: evidence from the McMurdo Ice Shelf

1996 ◽  
Vol 42 (142) ◽  
pp. 486-500 ◽  
Author(s):  
Thomas B. Kellogg ◽  
Terry Hughes ◽  
Davida E. Kellogg
Keyword(s):  
Ross Sea ◽  
Ice Sheet ◽  
Ice Shelf ◽  
Ice Streams ◽  
Mcmurdo Sound ◽  
Ross Ice Shelf ◽  
West Antarctic ◽  
Grounding Line ◽  
Glacier Ice ◽  
East And West

AbstractWe present new interpretations of deglaciation in McMurdo Sound and the western Ross Sea, with observationally based reconstructions of interactions between East and West Antarctic ice at the last glacial maximum (LGM), 16000, 12000, 8000 and 4000 BP. At the LGM, East Antarctic ice from Mulock Glacier split; one branch turned westward south of Ross Island but the other branch rounded Ross Island before flowing southwest into McMurdo Sound. This flow regime, constrained by an ice saddle north of Ross Island, is consistent with the reconstruction of Stuiver and others (1981a). After the LGM, grounding-line retreat was most rapid in areas with greatest water depth, especially along the Victoria Land coast. By 12000 BP, the ice-now regime in McMurdo Sound changed to through-flowing Mulock Glacier ice, with lesser contributions from Koettlitz, Blue and Ferrar Glaciers, because the former ice saddle north of Ross Island was replaced by a dome. The modern flew regime was established ∼4000 BP. Ice derived from high elevations on the Polar Plateau but now stranded on the McMurdo Ice Shelf, and the pattern of the Transantarctic Mountains erratics support our reconstructions of Mulock Glacier ice rounding Minna Bluff but with all ice from Skelton Glacier ablating south of the bluff. They are inconsistent with Drewry’s (1979) LGM reconstruction that includes Skelton Glacier ice in the McMurdo-Sound through-flow. Drewry’s (1979) model closely approximates our results for 12000-4000 BP. Ice-sheet modeling holds promise for determining whether deglaciation proceeded by grounding-line retreat of an ice sheet that was largely stagnant, because it never approached equilibrium flowline profiles after the Ross Ice Shelf grounded, or of a dynamic ice sheet with flowline profiles kept low by active ice streams that extended northward from present-day outlet glaciers after the Ross Ice Shelf grounded.

Glacial geology of the Torngat Mountains, Labrador

1988 ◽  
Vol 25 (8) ◽  
pp. 1184-1198 ◽  
Author(s):  
Peter U. Clark
Keyword(s):  
Soil Profile ◽  
Late Quaternary ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Glacial Geology ◽  
Coastal Regions ◽  
Radiocarbon Dates ◽  
Areal Distribution ◽  
Profile Development

Two late Quaternary alloformations are identifed throughout the Torngat Mountains by degree of soil profile development in till with a granitic composition, morphologic expression of deposits, and their relative areal distribution. The two alloformations are interpreted to represent two, successively limited glaciations of the Torngat Mountains by the Laurentide Ice Sheet. Deposits of the Shoal Cove Alloformation mantle hillslopes distal to deposits of the younger Saglek Alloformation. Deposits are primarily soliflucted till found around coastal regions. Soils developed in till of the Shoal Cove Alloformation are characterized by well-expressed Bw horizons ≥ 19 cm thick. Deposits of the younger Saglek Alloformation are characterized by prominent, well-preserved moraines, outwash fan surfaces, and ice-marginal channels. Soils described in till are poorly developed, with A horizons directly overlying Cox horizons, or separated from Cox horizons by thin, transitional (AC, CA) horizons or poorly expressed Bw horizons. During deposition of this alloformation, the Laurentide Ice Sheet was confined to major valleys and fiords, leaving large areas of the mountains ice free. Old radiocarbon dates on shells from diamictons on the Iron Strand coast do not provide a unique age for glacial events on the Labrador coast. Age of marine limit on the coast suggests deglaciation from the event depositing the Saglek Alloformation began 9 000 – 10 000 years BP.

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