scholarly journals Past Ice-Sheet Behaviour: Retreat Scenarios and Changing Controls in the Ross Sea, Antarctica

2016 ◽  
Author(s):  
Anna Ruth Halberstadt ◽  
Lauren M. Simkins ◽  
Sarah L. Greenwood ◽  
John B. Anderson
Keyword(s):  
Drainage Basin ◽  
Ross Sea ◽  
Ice Sheet ◽  
Small Scale ◽  
Swath Bathymetry ◽  
Geomorphic Features ◽  
Ice Sheet Dynamics ◽  
Lift Off ◽  
Glacial Landforms ◽  
Western Ross Sea

Abstract. Studying the history of ice-sheet behaviour in Antarctica's largest drainage basin, the Ross Sea, can improve our understanding of patterns, timing, and controls on marine-based ice-sheet dynamics, and provide constraints on numerical ice-sheet models. Newly collected high-resolution multibeam swath bathymetry data, combined with two decades of legacy multibeam and seismic data, are used to map glacial landforms and reconstruct paleodrainage. Last Glacial Maximum grounded ice reached the continental shelf edge in the eastern but not western Ross Sea. Recessional geomorphic features in the western Ross Sea indicate virtually continuous retreat of the ice sheet in contact with the bed. In the eastern Ross Sea, well-preserved linear features and a lack of small-scale recessional landforms record rapid lift-off of grounded ice from the bed. Physiography exerted a first-order control on ice behaviour, while seafloor geology played an important subsidiary role. Previously published grounding-line retreat scenarios are based on terrestrial observations; however, this study uses Ross Sea-wide geomorphology to constrain marine deglaciation. Our analysis of retreat patterns suggests that: (1) a large embayment formed in the eastern Ross Sea; (2) retreat was complex and asynchronous between troughs; and (3) the eastern Ross Sea largely deglaciated prior to the western Ross Sea.

scholarly journals Past ice-sheet behaviour: retreat scenarios and changing controls in the Ross Sea, Antarctica

2016 ◽  
Vol 10 (3) ◽  
pp. 1003-1020 ◽  
Author(s):  
Anna Ruth W. Halberstadt ◽  
Lauren M. Simkins ◽  
Sarah L. Greenwood ◽  
John B. Anderson
Keyword(s):  
High Resolution ◽  
Continental Shelf ◽  
Drainage Basin ◽  
Ross Sea ◽  
Numerical Models ◽  
Ice Sheet ◽  
Small Scale ◽  
Antarctic Ice Sheet ◽  
Grounding Line ◽  
Western Ross Sea

Abstract. Studying the history of ice-sheet behaviour in the Ross Sea, Antarctica's largest drainage basin can improve our understanding of patterns and controls on marine-based ice-sheet dynamics and provide constraints for numerical ice-sheet models. Newly collected high-resolution multibeam bathymetry data, combined with two decades of legacy multibeam and seismic data, are used to map glacial landforms and reconstruct palaeo ice-sheet drainage. During the Last Glacial Maximum, grounded ice reached the continental shelf edge in the eastern but not western Ross Sea. Recessional geomorphic features in the western Ross Sea indicate virtually continuous back-stepping of the ice-sheet grounding line. In the eastern Ross Sea, well-preserved linear features and a lack of small-scale recessional landforms signify rapid lift-off of grounded ice from the bed. Physiography exerted a first-order control on regional ice behaviour, while sea floor geology played an important subsidiary role. Previously published deglacial scenarios for Ross Sea are based on low-spatial-resolution marine data or terrestrial observations; however, this study uses high-resolution basin-wide geomorphology to constrain grounding-line retreat on the continental shelf. Our analysis of retreat patterns suggests that (1) retreat from the western Ross Sea was complex due to strong physiographic controls on ice-sheet drainage; (2) retreat was asynchronous across the Ross Sea and between troughs; (3) the eastern Ross Sea largely deglaciated prior to the western Ross Sea following the formation of a large grounding-line embayment over Whales Deep; and (4) our glacial geomorphic reconstruction converges with recent numerical models that call for significant and complex East Antarctic ice sheet and West Antarctic ice sheet contributions to the ice flow in the Ross Sea.

scholarly journals The Cordilleran Ice Sheet: One Hundred and Fifty Years of Exploration and Discovery

2007 ◽  
Vol 45 (3) ◽  
pp. 269-280 ◽  
Author(s):  
Lionel E. Jackson, ◽  
John J. Clague
Keyword(s):  
World War Ii ◽  
Research Effort ◽  
Ice Sheet ◽  
Early Period ◽  
Transitional Period ◽  
Marine Geology ◽  
Ice Sheet Dynamics ◽  
Cordilleran Ice Sheet ◽  
Regional Fluctuations ◽  
Glacial Landforms

ABSTRACT Present concepts about the Cordilleran Ice Sheet are the product of observations and ideas of several generations of earth scientists. The limits of glaciation in the Cordillera were established in the last half of the nineteenth century by explorers and naturalists, notably G. M. Dawson, R. G. McConnell, and T. C. Chamberlin. By the turn of the century, the gross configuration of the Cordilleran Ice Sheet had been determined, but the causes of glaciation and ice-sheet dynamics remained poorly understood. This early period of exploration and discovery was followed by a transitional period, from about 1900 to 1950, during which a variety of glacial landforms and deposits were explained (e.g., Channeled Scablands of Washington; "white silts" of southern British Columbia), and conceptual models of the growth and decay of the ice sheet were proposed. Shortly after World War II, there was a dramatic increase in research into all aspects of glaciation in the Canadian Cordillera which has continued unabated to the present. Part of the research effort during this period has been directed at resolving the Cordilleran Ice Sheet in both time and space. Local and regional fluctuations of the ice sheet have been reconstructed through stratigraphie and sedimentological studies, supported by radiocarbon and other dating techniques. Compilations of late Pleistocene ice-flow directions have shown that the Cordilleran Ice Sheet was a mass of coalescent glaciers flowing in a complex fashion from many montane source areas. During the postwar period, research has also begun or advanced significantly in several other disciplines, notably glaciology, process sedimen-tology, geomorphology, paleoecology, and marine geology. Attempts are now being made to quantitatively model the Cordilleran Ice Sheet using computers and the geological database assembled by past generations of earth scientists.

Regional-scale abrupt Mid-Holocene ice sheet thinning in the western Ross Sea, Antarctica

Geology ◽  
2020 ◽  
Author(s):  
R.S. Jones ◽  
R.J. Whitmore ◽  
A.N. Mackintosh ◽  
K.P. Norton ◽  
S.R. Eaves ◽  
...  
Keyword(s):  
Ross Sea ◽  
Numerical Models ◽  
Regional Scale ◽  
Ice Sheet ◽  
Outlet Glacier ◽  
Bed Topography ◽  
Geological Past ◽  
External Driver ◽  
Regional Sea Level ◽  
Western Ross Sea

Outlet glaciers drain the majority of ice flow in the Antarctic ice sheet. Theory and numerical models indicate that local bed topography can play a key role in modulating outlet glacier response to climate warming, potentially resulting in delayed, asynchronous, or enhanced retreat. However, the period of modern observations is too short to assess whether local or regional controls dominate ice sheet response on time scales that are critical for understanding ice sheet mass loss over this century and beyond. The recent geological past allows for insight into such centennial-scale ice sheet behavior. We present a cosmogenic surface-exposure chronology from Mawson Glacier, adjacent to a region of the Ross Sea that underwent dynamic marine-based ice sheet retreat following the Last Glacial Maximum. Our data record at least 220 m of abrupt ice thinning between 7.5 and 4.5 ka, followed by more gradual thinning until the last millennium. The timing, rates, and magnitudes of thinning at Mawson Glacier are remarkably similar to that documented 100 km to the south at Mackay Glacier. Together, both outlet glaciers demonstrate that abrupt deglaciation occurred across a broad region in the Mid-Holocene. This happened despite the complex bed topography of the western Ross Sea and implies an overarching external driver of retreat. When compared to regional sea-level and ocean-temperature changes, our data indicate that ocean warming most likely drove grounding-line retreat and ice drawdown, which then accelerated as a result of marine ice sheet instability.

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.

scholarly journals Supplemental Material: Regional-scale abrupt Mid-Holocene ice sheet thinning in the western Ross Sea, Antarctica

2020 ◽  
Author(s):  
Richard S. Jones ◽  
et al.
Keyword(s):  
Ross Sea ◽  
Regional Scale ◽  
Ice Sheet ◽  
Sample Information ◽  
Western Ross Sea

Supplemental table of sample information and detailed description of methods.<br>

scholarly journals Ice-Sheet Surface Elevation and Changes Observable by Satellite Radar Altimetry

1979 ◽  
Vol 24 (90) ◽  
pp. 491-493 ◽  
Author(s):  
H. Jay Zwally ◽  
R. L. Brooks ◽  
H. Ray Stanley ◽  
W. J. Campbell
Keyword(s):  
Drainage Basin ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
The State ◽  
Surface Elevation ◽  
Radar Altimeter ◽  
Major Question ◽  
The Status ◽  
Satellite Radar ◽  
Ice Sheet Dynamics

Abstract A major question in ice-sheet dynamics is the state of balance between the net mass input and ice flow. Since an imbalance produces a change in surface elevation, the state of balance can be studied by monitoring the elevation, and this has been accomplished by surface-leveling techniques in a few locations. Due to the requirement for accurate and repetitive measurements over large areas, it is not practical to determine the status of balance of an entire ice sheet or even a major drainage basin by conventional techniques. Now, recent results from satellite-borne radar altimeter measurements over the Greenland ice sheet demonstrate the feasibility of accurately measuring and monitoring the topography of large ice masses. The application of this new technique offers the possibility of making a meaningful mass-balance determination and for detecting actual or potential ice-sheet surges.

Multi-proxy analysis of Late Quaternary ODYSSEA Contourite Depositional System (Ross Sea, Antarctica) and the depositional record of contour current and cold, dense waters

2020 ◽  
Author(s):  
Michele Rebesco ◽  
Renata Giulia Lucchi ◽  
Andrea Caburlotto ◽  
Stefano Miserocchi ◽  
Leonardo Langone ◽  
...  
Keyword(s):  
Ross Sea ◽  
Late Quaternary ◽  
Ice Sheet ◽  
Current Strength ◽  
Global Ocean ◽  
General Assembly ◽  
Geophysical Research ◽  
Dense Water ◽  
Depositional System ◽  
Ice Sheet Dynamics

&lt;p&gt;The Ross Ice Shelf is the Antarctic region that over the last deglaciation experienced the greatest change in areal ice cover. Today, cold, dense and saline water masses (brines) produced in the Ross Sea polynya, flow from the shelf to the deep ocean providing a significant contribution to the propelling of the global ocean circulation regulating the climate. In particular, the Hillary Canyon in the Eastern Ross Sea is the main conduit through which brines descend the slope to reach the deeper ocean and is thus one of the greatest regions of cold, dense water export in the world.&lt;/p&gt;&lt;p&gt;A Contourite Depositional System (the ODYSSEA CDS) on the western flank of the Hillary Canyon is inferred to have been generated through several hundred-thousand years by along-slope, contour currents that transported and accumulated the sediments brought down the Hillary Canyon by means of brines. A multi-proxy investigation was conducted on the shallowest part of the ODYSSEA CDS depositional sequences, which we expect to contain i) the record of the brine formation, ii) the indication on contour current strength through time, and iii) their interplay and modulation associated to climate change.&lt;/p&gt;&lt;p&gt;Six gravity cores, collected in both the proximal and distal area of the ODYSSEA CDS, were studied through multi-proxy analyses including sediment physical properties (texture, structures, water content, wet bulk density), compositional characteristics (XRF, geochemistry and detrital apatite, zircon, and rutile U-Pb on ice-rafted debris) (Lucchi et al., 2019; Neofitu et al., 2020) and microfossil content (planktonic and benthic foraminifera, calcareous nannofossils and diatoms). An age model has been reconstructed combining palaeomagnetic record, biostratigraphic content, tephrochronology and AMS radiocarbon dating on planktonic foraminifera tests.&lt;/p&gt;&lt;p&gt;Inferred variations in dense water formation, contour current strength and &lt;strong&gt;ice sheet dynamics &lt;/strong&gt;are discussed in the light of our data interpretation.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Lucchi, R.G., Caburlotto, A., Miserocchi, S., Liu, Y., Morigi, C., Persico, D., Villa, G., Langone, L., Colizza, E., Macr&amp;#236;, P., Sagnotti, L., Conte, R., Rebesco, M., 2019. The depositional record of the Odyssea drift (Ross Sea, Antarctica). Geophysical Research Abstracts, Vol. 21, EGU2019-10409-1, 2019. EGU General Assembly, Vienna (Austria), 7&amp;#8211;12, April, 2019 (POSTER).&lt;/p&gt;&lt;p&gt;Neofitu, R., Mark, C., Rebesco, M., Lucchi, R.G., Douss, N., Morigi, C., Kelley, S., Daly, J.S., 2020. Tracking Late Quaternary ice sheet dynamics by multi-proxy detrital mineral U-Pb analysis: A case study from the Odyssea contourite, Ross Sea, Antarctica. Geophysical Research Abstracts. EGU General Assembly, Vienna (Austria), 3&amp;#8211;8, May, 2020 (POSTER for session CL1.11).&lt;/p&gt;

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