Measuring multiple cosmogenic nuclides in glacial cobbles sheds light on Greenland Ice Sheet processes

Corbett, Lee B.; Bierman, Paul R.; Neumann, Thomas; Graly, Joseph A.; Shakun, Jeremy D.; Goehring, Brent M.; Hidy, Alan J.; Caffee, Marc W.

doi:10.1016/j.epsl.2020.116673

Cited by 6 publications

(3 citation statements)

References 45 publications

(78 reference statements)

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“…In western Greenland, Strunk et al (2017) use the lack of inherited 10 Be in some surficial bedrock samples to suggest that >50 m Myr -1 of denudation must have taken place during the Pleistocene. Finally, Corbett et al (2021) posit that cobbles emerging directly from the GrIS in western Greenland were sourced from deeply eroded interior landscapes that, at minimum, experienced ~20-50 m Myr -1 erosion over the Pleistocene.…”

Section: Modeled Orbital-and Centennial-scale Erosion Ratesmentioning

confidence: 99%

Centennial- and orbital-scale erosion beneath the Greenland Ice Sheet

Balter-Kennedy¹,

Young²,

Briner³

et al. 2021

Preprint

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Erosion beneath glaciers and ice sheets is a fundamental Earth-surface process dictating landscape development, which in turn influences ice-flow dynamics and the climate sensitivity of ice masses. The rate at which subglacial erosion takes place, however, is notoriously difficult to observe because it occurs beneath modern glaciers in a largely inaccessible environment. Here, we present 1) cosmogenic-nuclide measurements from bedrock surfaces with well constrained exposure and burial histories fronting Jakobshavn Isbræ in western Greenland to constrain centennial-scale erosion rates, and 2) a new method combining cosmogenic nuclide measurements in a shallow bedrock core with cosmogenic-nuclide modelling to constrain orbital-scale erosion rates across the same landscape. Twenty-six 10Be measurements in surficial bedrock constrain the erosion rate during historical times to 0.4–0.8 mm yr-1. Seventeen 10Be measurements in a 4-m-long bedrock core corroborate this centennial-scale erosion rate, and reveal that 10Be concentrations below ~2 m depth are greater than what is predicted by an idealized production-rate depth profile. We utilize this excess 10Be at depth to constrain orbital-scale erosion rates at Jakobshavn Isbræ to 0.1–0.3 mm yr-1. The broad similarity between centennial- and orbital-scale erosion rates suggests that subglacial erosion rates have remained relatively uniform throughout the Pleistocene at Jakobshavn Isbræ.

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Section: Modeled Orbital-and Centennial-scale Erosion Ratesmentioning

confidence: 99%

Centennial- and orbital-scale erosion beneath the Greenland Ice Sheet

Balter-Kennedy¹,

Young²,

Briner³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…In western Greenland, Strunk et al (2017) use the lack of inherited 10 Be in some surficial bedrock samples to suggest that >50 m Myr −1 of denudation must have taken place during the Pleistocene. Finally, Corbett et al (2021) posit that cobbles emerging directly from the GrIS in western Greenland were sourced from deeply eroded interior landscapes that, at minimum, experienced ∼20-50 m Myr −1 erosion over the Pleistocene. Our long-term erosion rate is consistent with these previous estimates, but provides more specificity in that it does not rely on a lack of inheritance (which gives a minimum estimate) but rather on the presence of inherited muon-produced 10 Be that holds direct information about erosion rates on orbital timescales.…”

Section: Comparison To Other Erosion Rate Estimatesmentioning

confidence: 99%

Centennial‐ and Orbital‐Scale Erosion Beneath the Greenland Ice Sheet Near Jakobshavn Isbræ

et al. 2021

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“…Terrestrial archives are rare and discontinuous, including sediment deposits (e.g. Funder and others, 2001; Bennike and others, 2010; Corbett and others, 2021; Larsen and others, 2021), ice-core basal ice layer (BIL) debris and bedrock (e.g. Souchez and others, 1994; Verbeke and others, 2002; Willerslev and others, 2007; Bender and others, 2010; Bierman and others, 2016; Goossens and others, 2016; Schaefer and others, 2016; Yau and others, 2016 a , 2016 b ; Christ and others, 2021).…”

Section: Introductionmentioning

confidence: 99%

Basal debris of the NEEM ice core, Greenland: a window into sub-ice-sheet geology, basal ice processes and ice-sheet oscillations

Blard¹,

Protin²,

Tison³

et al. 2023

J. Glaciol.

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We present new data from the debris-rich basal ice layers of the NEEM ice core (NW Greenland). Using mineralogical observations, SEM imagery, geochemical data from silicates (meteoric 10Be, εNd, 87Sr/86Sr) and organic material (C/N, δ13C), we characterize the source material, succession of previous glaciations and deglaciations and the paleoecological conditions during ice-free episodes. Meteoric 10Be data and grain features indicate that the ice sheet interacted with paleosols and eroded fresh bedrock, leading to mixing in these debris-rich ice layers. Our analysis also identifies four successive stages in NW Greenland: (1) initial preglacial conditions, (2) glacial advance 1, (3) glacial retreat and interglacial conditions and (4) glacial advance 2 (current ice-sheet development). C/N and δ13C data suggest that deglacial environments favored the development of tundra and taiga ecosystems. These two successive glacial fluctuations observed at NEEM are consistent with those identified from the Camp Century core basal sediments over the last 3 Ma. Further inland, GRIP and GISP2 summit sites have remained glaciated more continuously than the western margin, with less intense ice-substratum interactions than those observed at NEEM.

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Measuring multiple cosmogenic nuclides in glacial cobbles sheds light on Greenland Ice Sheet processes

Cited by 6 publications

References 45 publications

Centennial- and orbital-scale erosion beneath the Greenland Ice Sheet

Centennial- and orbital-scale erosion beneath the Greenland Ice Sheet

Centennial‐ and Orbital‐Scale Erosion Beneath the Greenland Ice Sheet Near Jakobshavn Isbræ

Basal debris of the NEEM ice core, Greenland: a window into sub-ice-sheet geology, basal ice processes and ice-sheet oscillations

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