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

Jones, Richard S.; Whitmore, Ross; Mackintosh, Andrew; Norton, Kevin; Eaves, Shaun; Stutz, Jamey; Christl, Marcus

doi:10.1130/g48347.1

Cited by 15 publications

(17 citation statements)

References 31 publications

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“…The model used in this study (Úa) is available from Gudmundsson (2019; https://doi.org/10.5281/zenodo.3706624), while the geological data used are archived at ICE-D (http://antarctica.ice-d.org/) and described in Jones et al (2015) and Jones et al (2020). The model output can be made available upon request.…”

Section: Data Availability Statementmentioning

confidence: 99%

“…(gray crosses; Hall & Denton, 2004; Licht et al., 1996), as well as east of Ross Island and north of the Drygalski Ice Tongue in Terra Nova Bay (Baroni & Hall, 2004; McKay et al., 2016). Onshore, ice thinning is recorded at Mackay Glacier (Jones et al., 2015), with elevation transects at Gondola Ridge (red triangle) and Low Ridge (blue diamond), and at Mawson Glacier (Jones et al., 2020), with elevation transects at Bruce Point (purple circle) and Mt Murray (orange square). The red boundary represents the 2‐D ice‐flow model domain that we used in this study to investigate grounding‐line migration and upstream ice thickness change.…”

Section: Introductionmentioning

confidence: 99%

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Ocean‐Driven and Topography‐Controlled Nonlinear Glacier Retreat During the Holocene: Southwestern Ross Sea, Antarctica

Jones

Gudmundsson

Mackintosh

et al. 2021

Geophysical Research Letters

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Recent ice sheet mass loss in Antarctica has been attributed to an influx of warm ocean waters, which drove grounding‐line retreat and ice thinning. Episodic retreat and rapid thinning also occurred in the southwestern Ross Sea during the Holocene, which today accommodates cold ocean waters. We applied finite element ice‐flow modeling to investigate the roles of ocean temperature and bed topography in the deglaciation of this region. First, our experiments demonstrate that bed topography controlled the spatial pattern of grounding‐line retreat. Topographic pinning points limited the rate of ice loss until retreat progressed beyond a bathymetric threshold. Second, ocean thermal forcing determined the timing of this ice loss. Enhanced ocean‐driven melt is required during the Early‐to‐Mid Holocene to replicate geological records of deglaciation, possibly indicating that warm ocean waters were once present in this region. On multi‐centennial timescales, ocean temperature drove, while bed topography controlled, nonlinear rates of ice mass loss.

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Section: Data Availability Statementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ocean‐Driven and Topography‐Controlled Nonlinear Glacier Retreat During the Holocene: Southwestern Ross Sea, Antarctica

Jones

Gudmundsson

Mackintosh

et al. 2021

Geophysical Research Letters

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“…Clasts from the head of the Skelton Glacier drainage basin likely record multiple episodes of exposure during interglacials and burial below ice during glacial periods from the Pliocene to Pleistocene, which is compatible with increased ice thickness during MIS 8 (Jones et al, 2017). At lower elevations along Skelton Glacier, most samples record ice-thinning fol- (Jouzel et al, 2007). (c) Exposure ages (± 1σ error) of Ross Sea drift (yellow circles) and older pre-LGM deposits (orange circles), and the Upper Discovery deposit (purple).…”

Section: Upper Discovery Deposit: Maximum Glaciation Of Mcmurdo Soundmentioning

confidence: 95%

“…(a) Marine Isotope Stage boundaries showing interglacial (light red) and glacial (light blue) periods, and global mean sea level (Spratt and Lisiecki, 2016) -dashed blue lines show minimum global sea level during the LGM and MIS 8. (b) Temperature difference from modern in the EPICA Dome C ice core in East Antarctica(Jouzel et al, 2007). (c) Exposure ages (± 1σ error) of Ross Sea drift (yellow circles) and older pre-LGM deposits (orange circles), and the Upper Discovery deposit (purple).…”

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confidence: 99%

Cosmogenic nuclide exposure age scatter records glacial history and processes in McMurdo Sound, Antarctica

et al. 2021

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Abstract. The preservation of cosmogenic nuclides that accumulated during periods of prior exposure but were not subsequently removed by erosion or radioactive decay complicates interpretation of exposure, erosion, and burial ages used for a variety of geomorphological applications. In glacial settings, cold-based, non-erosive glacier ice may fail to remove inventories of inherited nuclides in glacially transported material. As a result, individual exposure ages can vary widely across a single landform (e.g., moraine) and exceed the expected or true depositional age. The surface processes that contribute to inheritance remain poorly understood, thus limiting interpretations of cosmogenic nuclide datasets in glacial environments. Here, we present a compilation of new and previously published exposure ages of multiple lithologies in local Last Glacial Maximum (LGM) and older Pleistocene glacial sediments in the McMurdo Sound region of Antarctica. Unlike most Antarctic exposure chronologies, we are able to compare exposure ages of local LGM sediments directly against an independent radiocarbon chronology of fossil algae from the same sedimentary unit that brackets the age of the local LGM between 12.3 and 19.6 ka. Cosmogenic exposure ages vary by lithology, suggesting that bedrock source and surface processes prior to, during, and after glacial entrainment explain scatter. 10Be exposure ages of quartz in granite, sourced from the base of the stratigraphic section in the Transantarctic Mountains, are scattered but young, suggesting that clasts entrained by sub-glacial plucking can generate reasonable apparent exposure ages. 3He exposure ages of pyroxene in Ferrar Dolerite, which crops out above outlet glaciers in the Transantarctic Mountains, are older, which suggests that clasts initially exposed on cliff faces and glacially entrained by rock fall carry inherited nuclides. 3He exposure ages of olivine in basalt from local volcanic bedrock in the McMurdo Sound region contain many excessively old ages but also have a bimodal distribution with peak probabilities that slightly pre-date and post-date the local LGM; this suggests that glacial clasts from local bedrock record local landscape exposure. With the magnitude and geological processes contributing to age scatter in mind, we examine exposure ages of older glacial sediments deposited by the most extensive ice sheet to inundate McMurdo Sound during the Pleistocene. These results underscore how surface processes operating in the Transantarctic Mountains are expressed in the cosmogenic nuclide inventories held in Antarctic glacial sediments.

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“…7). There is some evidence for discharge of Antarctic ice during the early Holocene (Small et al, 2019;Jones et al, 2021), which has the potential to contribute to the cool conditions inferred from the composite Southern Alps moraine record (Fig. 7).…”

Section: Climatic Drivers Of Observed Glacier Trendsmentioning

confidence: 99%

Local summer insolation and greenhouse gas forcing drove warming and glacier retreat in New Zealand during the Holocene

Dowling

Eaves

Norton

et al. 2021

Quaternary Science Reviews

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Geological climate archives from the Holocene Epoch provide baseline information concerning natural climate variability. Temperate mountain glacier extent is sensitive to summer air temperature, thus geological records of past glacier length changes are a useful proxy for this climatic variable. Here we present a new cosmogenic 10 Be chronology of glacier length changes at Dart Glacier in the Southern Alps, New Zealand. Prominent moraines deposited 321 ± 44 yr ago (n ¼ 11) and 7.8 ± 0.3 ka (n ¼ 5) show glaciers during the Little Ice Age were less extensive than during the early Holocene. This pattern of net Holocene glacier retreat is consistent with emerging data from other catchments in New Zealand and across the southern mid-latitudes. Using the physical framework of a transient global climate model simulation, we suggest that cool summers in the early Holocene were promoted by the local summer insolation minimum, together with low atmospheric greenhouse gas concentrations, causing an early Holocene austral glacial maximum. An insolation-driven reduction in seasonality at southern midlatitudes may reconcile differences between early Holocene temperature reconstructions where climate proxies have different seasonal sensitivities. We suggest that rising greenhouse gas concentrations after 7 ka caused regional-scale glacier retreat and appear to be the dominant driver of multimillennial summer temperature trends in the southern mid-latitudes during the present interglacial.

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

Cited by 15 publications

References 31 publications

Ocean‐Driven and Topography‐Controlled Nonlinear Glacier Retreat During the Holocene: Southwestern Ross Sea, Antarctica

Ocean‐Driven and Topography‐Controlled Nonlinear Glacier Retreat During the Holocene: Southwestern Ross Sea, Antarctica

Cosmogenic nuclide exposure age scatter records glacial history and processes in McMurdo Sound, Antarctica

Local summer insolation and greenhouse gas forcing drove warming and glacier retreat in New Zealand during the Holocene

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