Piston-core based biostratigraphic constraints on Pleistocene oscillations of the West Antarctic Ice Sheet in western Ross Sea between North Basin and AND-1B drill site

Bart, Philip J.; Sjunneskog, Charlotte; Chow, J. M.

doi:10.1016/j.margeo.2011.09.005

Cited by 27 publications

(14 citation statements)

References 28 publications

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“…In contrast, Sites U1521 and U1522 provide intervals of more continuous sedimentation (albeit with some periods of erosion during large glaciations) because they are in paleobathymetric depressions that provided the accommodation space needed for preservation after ice expansion . These sites are also farther out on the continental shelf, near the paleoshelf break ( Figure F7), and are therefore less likely to be frequently overridden by grounded ice (Pollard and DeConto, 2009;Bart et al, 2011). More continuous records of oceanographic change were recovered at Sites U1523-U1525, providing high-latitude information on late Neogene and Quaternary ocean and atmospheric temperatures, meltwater input, and bottom water production.…”

Section: Reconstruct Ice-proximal Atmospheric and Oceanic Temperaturesmentioning

confidence: 99%

“…Seismic facies above RSU2 are indicative of till sheets bound by erosional unconformities in an aggrading shelf margin caused by shelf-wide advances of the WAIS (Figure F7) (Alonso et al, 1992;Brancolini et al, 1995;Bart et al, 2011). Unlike other sectors of the Antarctic, the eastern Ross Sea trough mouth contains thick (~2000 m) sedimentary sequences on the shelf and upper continental slope that may contain a detailed WAIS history.…”

Section: Magmatic Intrusionsmentioning

confidence: 99%

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Ross Sea West Antarctic Ice Sheet History

McKay¹,

Santis²,

Kulhanek³

et al. 2019

Proceedings of the International Ocean Discovery Program

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The marine-based West Antarctic Ice Sheet (WAIS) is currently locally retreating because of shifting wind-driven oceanic currents that transport warm waters toward the ice margin, resulting in ice shelf thinning and accelerated mass loss. Previous results from geologic drilling on Antarctica's continental margins show significant variability in ice sheet extent during the late Neogene and Quaternary. Climate and ice sheet models indicate a fundamental role for oceanic heat in controlling ice sheet variability over at least the past 20 My. Although evidence for past ice sheet variability is available from ice-proximal marine settings, sedimentary sequences from the continental shelf and rise are required to evaluate the extent of past ice sheet variability and the associated forcings and feedbacks. International Ocean Discovery Program Expedition 374 drilled a latitudinal and depth transect of five sites from the outer continental shelf to rise in the central Ross Sea to resolve Neogene and Quaternary relationships between climatic and oceanic change and WAIS evolution. The Ross Sea was targeted because numerical ice sheet models indicate that this sector of Antarctica responds sensitively to changes in ocean heat flux. Expedition 374 was designed for optimal data-model integration to enable an improved understanding of Antarctic Ice Sheet (AIS) mass balance during warmer-than-present climates (e.g., the Pleistocene "super interglacials," the mid-Pliocene, and the Miocene Climatic Optimum). The principal goals of Expedition 374 were to • Evaluate the contribution of West Antarctica to far-field ice volume and sea level estimates;• Reconstruct ice-proximal oceanic and atmospheric temperatures to quantify past polar amplification; • Assess the role of oceanic forcing (e.g., temperature and sea level) on AIS variability; • Identify the sensitivity of the AIS to Earth's orbital configuration under a variety of climate boundary conditions; and • Reconstruct Ross Sea paleobathymetry to examine relationships between seafloor geometry, ice sheet variability, and global climate.To achieve these objectives, postcruise studies will• Use data and models to reconcile intervals of maximum Neogene and Quaternary ice advance and retreat with far-field records of eustatic sea level; • Reconstruct past changes in oceanic and atmospheric temperatures using a multiproxy approach; • Reconstruct Neogene and Quaternary sea ice margin fluctuations and correlate these records to existing inner continental shelf records; • Examine relationships among WAIS variability, Earth's orbital configuration, oceanic temperature and circulation, and atmospheric pCO 2 ; and • Constrain the timing of Ross Sea continental shelf overdeepening and assess its impact on Neogene and Quaternary ice dynamics.Expedition 374 departed from Lyttelton, New Zealand, in January 2018 and returned in March 2018. We recovered 1292.70 m of R.M. McKay et al. Expedition 374 summary IODP Proceedings 2 V o l u m e 3 7 4

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Section: Reconstruct Ice-proximal Atmospheric and Oceanic Temperaturesmentioning

confidence: 99%

Section: Magmatic Intrusionsmentioning

confidence: 99%

Ross Sea West Antarctic Ice Sheet History

McKay¹,

Santis²,

Kulhanek³

et al. 2019

Proceedings of the International Ocean Discovery Program

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“…The geometry and size of these systems are rather atypical of a subglacial domain: The systems bifurcate from a point (rather than a line/area) source and are both larger and considerably less intricate than the nearby Wright Valley Labyrinth channels attributed to massive subglacial fl oods in the mid-Miocene . Furthermore, albeit large in size, we question their potential for preservation given repeated grounding and retreat of Ross Sea ice throughout the PliocenePleistocene (Alonso et al, 1992;Naish et al, 2007Naish et al, , 2009McKay et al, 2009;Bart et al, 2011). We also rule out formation in a single episode of ice-dammed lake drainage from the "upstream" Taylor Valley, where proglacial lakes have been reconstructed (Stuiver et al, 1981;Denton et al, 1989;Hall et al, 2000;Wagner et al, 2006).…”

Section: Channelsmentioning

confidence: 99%

Ice-flow switching and East/West Antarctic Ice Sheet roles in glaciation of the western Ross Sea

Greenwood

Gyllencreutz

Jakobsson

et al. 2012

Geological Society of America Bulletin

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The long-term behavior of the East and West Antarctic Ice Sheets, and their respective responses to forcing provide essential context for assessment of modern dynamic changes in ice-fl ow regimes and ice-sheet and shelf margins. The western Ross Sea discharges ice from both the East and West Antarctic Ice Sheets, and the paleoglacial record from this region is therefore valuable in unraveling their long-term behavior. New, high-resolution multibeam bathymetric data reveal snapshots of well-preserved glacial landforms on the seafl oor around Ross Island and McMurdo Sound. Glacial lineations, grounding zone wedges, draped recessional moraines, and meltwater channels record a series of different ice-fl ow events in the region, contradictions between which require major phases of ice-fl ow reorganization. From the glacial geomorphology, we reconstruct a four-stage model of ice-fl ow evolution for the last glacial cycle, consisting of: (1) northeastward fl ow into the Ross Sea from McMurdo Sound; (2) westward fl ow from the Ross Sea, around Ross Island, and onto the Victoria Land coast and coastal seafl oor trough; (3) a deglacial phase of ice-sheet thinning, minor shifts in fl ow, and grounding line retreat into McMurdo Sound; and (4) grounding line pinning on Ross Island during regional retreat, uncoupling of a remnant Ross Island ice cap, and local oscillation of Victoria Land outlet glaciers. We fi nd that East Antarctic Ice Sheet ice discharge had a strong infl uence on ice-fl ow geometry in this part of the Ross Sea during the last glacial stage, but that it was not necessarily in phase with the behavior of the West Antarctic Ice Sheet. It is similarly evident that the ice streams that drained the Ross Sea over the continental shelf at the Last Glacial Maximum did not all operate synchronously, and exerted different drawdown power at different times. Finally, we conclude that Ross Island acts as an important pinning point in the Ross Sea ice-sheet-shelf system, stabilizing grounding line retreat and encouraging lasting ice-shelf development.

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“…Several previous investigations of WAIS retreat have focused on western and central Ross Sea troughs (i.e., Drygalski, Joides, Pennell, and Glomar Challenger Basins, see Figure 1a) (e.g., Bart et al, 2011;Bart & Owolana, 2012;Howat & Domack, 2003;Licht et al, 1999;Shipp et al, 1999;Tolotti et al, 2013). Fewer studies have focused on eastern Ross Sea troughs (e.g., Whales Deep and Little America Basins).…”

Section: Multistep Retreat Of Grounded Ice From the Whales Deep Basinmentioning

confidence: 99%

Post‐LGM Grounding‐Line Positions of the Bindschadler Paleo Ice Stream in the Ross Sea Embayment, Antarctica

2017

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The West Antarctic Ice Sheet (WAIS) retreated more than 1,000 km since last grounding at the Ross Sea outer continental shelf. Here we show an interpretation of former grounding line positions from a new large‐area multibeam survey and a regional grid of chirp cross‐sectional data from the Whales Deep Basin in eastern Ross Sea. The basin is a paleo‐glacial trough that was occupied by the Bindschadler Ice Stream when grounded ice advanced to the shelf edge during the Last Glacial Maximum. These new geophysical data provide unambiguous evidence that the WAIS occupied at least seven grounding line positions within 60 km of the shelf edge. Four of seven grounding zone wedges (GZWs) are partly exposed over large areas of the trough. The overlapping stratal arrangement created a large‐volume compound GZW. Some of the groundings involved local readvance of the grounding line. Subsequent to these seven outer continental shelf groundings, the ice sheet retreated more than 200 km towards Roosevelt Island on the middle continental shelf. The major retreat across the middle continental shelf is recorded by small‐scale moraine ridges that mantle the top of GZW7, and these are suggestive of relatively continuous grounding line recession. The results indicate that retreat was considerably more complex than was possible to reconstruct with reconnaissance‐level data. The added details are important to climate models, which must first be able to reproduce the recent retreat pattern in all of its complexities to improve confidence in model predictions of the system's future response.

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Piston-core based biostratigraphic constraints on Pleistocene oscillations of the West Antarctic Ice Sheet in western Ross Sea between North Basin and AND-1B drill site

Cited by 27 publications

References 28 publications

Ross Sea West Antarctic Ice Sheet History

Ross Sea West Antarctic Ice Sheet History

Ice-flow switching and East/West Antarctic Ice Sheet roles in glaciation of the western Ross Sea

Post‐LGM Grounding‐Line Positions of the Bindschadler Paleo Ice Stream in the Ross Sea Embayment, Antarctica

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