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

Halberstadt, Anna Ruth W.; Simkins, Lauren M.; Greenwood, Sarah L.; Anderson, John B.

doi:10.5194/tc-10-1003-2016

Cited by 121 publications

(191 citation statements)

References 107 publications

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“…Vulnerability of WAIS to future warming can be assessed by investigating how it has responded to different climate regimes in the past. Unfortunately, geologic evidence of the past size and extent of Antarctic ice sheets is spatially sparse, tends to have large chronological uncertainty, and is sometimes 10 contradictory (Whitehouse et al, 2012;Anderson et al, 2014;Bentley et al, 2014;Clark and Tarasov, 2014;Halberstadt et al, 2016;McKay et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…The Ross Embayment is the largest drainage of WAIS, both in terms of area and mass loss (Halberstadt et al, 2016). The glacial history of WAIS in the Ross Sea has been speculated about since Captain James Ross first mapped its edge in 1841-1842, followed by the first geologic studies of the region during the Discovery, Nimrod, and Terra Nova expeditions (Scott, 1907;15 David et al, 1910-11;Debenham, 1921).…”

Section: Introductionmentioning

confidence: 99%

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An 83 000 year old ice core from Roosevelt Island, Ross Sea, Antarctica

Lee¹,

Brook²,

Bertler³

et al. 2018

Preprint

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Abstract. In 2013, an ice core was recovered from Roosevelt Island in the Ross Sea, Antarctica, as part of the Roosevelt Island Climate Evolution (RICE) project. Roosevelt Island is located between two submarine troughs carved by paleo-ice-streams.The RICE ice core provides new important information about the past configuration of the West Antarctic Ice Sheet and its retreat during the most recent deglaciation. In this work, we present the RICE17 chronology and discuss preliminary observations from the new records of methane, the isotopic composition of atmospheric molecular oxygen (δ 18O atm ), the isotopic 5 composition of atmospheric molecular nitrogen (δ 15 N-N 2 ), and total air content (TAC). RICE17 is a composite chronology combining annual layer interpretations, gas synchronization, and firn modeling strategies in different sections of the core. An automated matching algorithm is developed for synchronizing the high-resolution section of the RICE gas records (60-720 m, 1971 CE to 30 ka) to corresponding records from the WAIS Divide ice core, while deeper sections are manually matched. Ice age for the top 343 m (2635 yr BP, before 1950 C.E.) is derived from annual layer interpretations and described in the accom-10 panying paper by Winstrup et al. (2017). For deeper sections, the RICE17 ice age scale is based on the gas age constraints and the ice age-gas age offset estimated by a firn densification model. Novel aspects of this work include: 1) stratigraphic matching of centennial-scale variations in methane for pre-anthropogenic time periods, a strategy which will be applicable for developing precise chronologies for future ice cores, 2) the observation of centennial-scale variability in methane throughout the Holocene which suggests that similar variations during the late pre-15 industrial period need not be anthropogenic, and 3) the observation of continuous climate records dating back to ∼65 ka which provide evidence that the Roosevelt Island Ice Dome was a constant feature throughout the last glacial period.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An 83 000 year old ice core from Roosevelt Island, Ross Sea, Antarctica

Lee¹,

Brook²,

Bertler³

et al. 2018

Preprint

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“…Lateral drag increases as the width narrows, which may lead to ice stabilization that could result in transverse features, based on the amount of sediment flux and duration of the stillstand (Howat and Domack, 2003;Dowdeswell and Vasquez, 2013). Transverse-to-flow features in the Ross Sea and Weddell Sea (Halberstadt et al, 2016;Campo et al, 2017) are larger than the GZW and moraines identified in this study and are the result of a much larger ice flow system. Therefore, width may play a major role in confined flow, e.g.…”

Section: Geometry Of Baysmentioning

confidence: 59%

“…4, 5). The geometry of these transverse ridges is similar to much larger GZW in the Ross Sea (Halberstadt et al, 2016) and the Weddell Sea (Campo et al, 2017). The size of the GZW has been correlated with the length of ice stability (Alley et al, 2007;Dowdeswell and Vasquez, 2013;Batchelor and Dowdeswell, 2015), a larger GZW imply a longer period of ice stability.…”

Section: Ice-marginal Landforms Large Transverse Ridges: Grounding Zomentioning

confidence: 66%

Seafloor geomorphology of western Antarctic Peninsula bays: a signature of ice flow behaviour

Munoz

Wellner

2018

The Cryosphere

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Abstract. Glacial geomorphology is used in Antarctica to reconstruct ice advance during the Last Glacial Maximum and subsequent retreat across the continental shelf. Analogous geomorphic assemblages are found in glaciated fjords and are used to interpret the glacial history and glacial dynamics in those areas. In addition, understanding the distribution of submarine landforms in bays and the local controls exerted on ice flow can help improve numerical models by providing constraints through these drainage areas. We present multibeam swath bathymetry from several bays in the South Shetland Islands and the western Antarctic Peninsula. The submarine landforms are described and interpreted in detail. A schematic model was developed showing the features found in the bays: from glacial lineations and moraines in the inner bay to grounding zone wedges and drumlinoid features in the middle bay and streamlined features and meltwater channels in the outer bay areas. In addition, we analysed local variables in the bays and observed the following: (1) the number of landforms found in the bays scales to the size of the bay, but the geometry of the bays dictates the types of features that form; specifically, we observe a correlation between the bay width and the number of transverse features present in the bays. (2) The smaller seafloor features are present only in the smaller glacial systems, indicating that short-lived atmospheric and oceanographic fluctuations, responsible for the formation of these landforms, are only recorded in these smaller systems. (3) Meltwater channels are abundant on the seafloor, but some are subglacial, carved in bedrock, and some are modern erosional features, carved on soft sediment. Lastly, based on geomorphological evidence, we propose the features found in some of the proximal bay areas were formed during a recent glacial advance, likely the Little Ice Age.

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“…Topographical base map from USGS (1967) coastal ice morphology, surface gradients and surface elevations were probably broadly similar to today (e.g. Denton and Hughes 2002; Anderson et al 2014;Halberstadt et al 2016). Exposure of the bedrock ridges at Harrow Peaks took place only a few thousand years prior to the timing of grounding line retreating to the south of Wood Bay.…”

Section: Environmental Implicationsmentioning

confidence: 99%

A tuff cone erupted under frozen-bed ice (northern Victoria Land, Antarctica): linking glaciovolcanic and cosmogenic nuclide data for ice sheet reconstructions

et al. 2017

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The remains of a small volcanic centre are preserved on a thin bedrock ridge at Harrow Peaks, northern Victoria Land, Antarctica. The outcrop is interpreted as a monogenetic tuff cone relict formed by a hydrovolcanic (phreatomagmatic) eruption of mafic magma at 642 ± 20 ka (by 40 Ar-39 Ar), corresponding to the peak of the Marine Isotope Stage 16 (MIS16) glacial. Although extensively dissected and strewn with glacial erratics, the outcrop shows no evidence for erosion by ice. From interpretation of the lithofacies and eruptive mechanisms, the weight of the evidence suggests that eruptions took place under a cold-based (frozen-bed) ice sheet. This is the first time that a tuff cone erupted under cold ice has been described. The most distinctive feature of the lithofacies is the dominance of massive lapilli tuff rich in fine ash matrix and abraded lapilli. The lack of stratification is probably due to repeated eruption through a conduit blasted through the ice covering the vent. The ice thickness is uncertain but it might have been as little as 100 m and the preserved tephra accumulated mainly as a crater (or ice conduit) infill. The remainder of the tuff cone edifice was probably deposited supraglacially and underwent destruction by ice advection and, particularly, collapse during a younger interglacial. Dating using 10 Be cosmogenic exposure of granitoid basement erratics indicates that the erratics are unrelated to the eruptive period. The 10 Be ages suggest that the volcanic outcrop was most recently exposed by ice decay at c. 20.8 ± 0.8 ka (MIS2) and the associated ice was thicker than at 642 ka and probably polythermal rather than cold-based, which is normally assumed for the period.

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

Cited by 121 publications

References 107 publications

An 83 000 year old ice core from Roosevelt Island, Ross Sea, Antarctica

An 83 000 year old ice core from Roosevelt Island, Ross Sea, Antarctica

Seafloor geomorphology of western Antarctic Peninsula bays: a signature of ice flow behaviour

A tuff cone erupted under frozen-bed ice (northern Victoria Land, Antarctica): linking glaciovolcanic and cosmogenic nuclide data for ice sheet reconstructions

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