Modelling subglacial erosion and englacial sediment transport of the North American ice sheets

Hildes, D. H.

doi:10.14288/1.0052346

Cited by 2 publications

(10 citation statements)

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“…We plan on providing sediment cover and bed elevation anomaly during interglacials for a range of parameterizations and welcome reasonable suggestions for additional outputs. between Boulton and Hallet style erosion whereas Hildes (2001) uses only Hallet. Hildes (2001) input a map of substrate lithology and track the distribution of clast lithology within a given cell, calculating the relative hardness of substrate and abrasive.…”

Section: Discussionmentioning

confidence: 99%

“…Abrasion is switched off when clast hardness is lower than the substrate, whereas Melanson (2012) neglects the clastsubstrate hardness differential. Hildes (2001) also uses lithology dependent quarrying rate factors, although the accuracy of this is questionable as quarrying primarily relies on the density of pre-existing joints and weaknesses in the substrate (Hooyer et al, 2012;Iverson, 2012). Joint and fracture density is not easily quantified at the relevant scales and is highly variable within the dimension of a grid cell (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…The sediment model (Melanson, 2012) applied in the Glacial Systems Model (GSM) is designed after that of Hildes (2001).…”

Section: Model Of Glacial Sedimentationmentioning

confidence: 99%

“…Both employ separate descriptions of abrasion and quarrying for the sediment production part, although Melanson (2012) provides an optional empirical sediment production as well as a choice between Boulton and Hallet style abrasion whereas Hildes (2001) uses only Hallet. Hildes (2001) tracks relative hardness of substrate and abrasive, abrasion ceases when the latter is less than the former, whereas Melanson (2012) assumes the abrading particle is always harder than the substrate.…”

Section: Model Of Glacial Sedimentationmentioning

confidence: 99%

“…h sed is the sediment layer thickness and h⋆ sed is a characteristic thickness for shielding (shielding factor). This shielding factor is taken by Hildes (2001) to represent the areal fraction of the rough bed within a given cell which is covered by sediment. Hildes (2001) calculates this as…”

Section: B1 Abrasion Lawmentioning

confidence: 99%

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North American Pleistocene Glacial Erosion and Thin Pliocene Regolith Thickness Inferred from Data-Constrained Fully Coupled Ice-Climate-Sediment modelling

Drew,

Tarasov

2024

Preprint

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Abstract. Beyond the impact of glacial isostatic adjustment, landscape evolution is typically neglected at large scale when considering the basal boundary condition for ice sheet and climate modelling over past glacial cycles. Erosion and changing sediment loads impact bed elevation, land/sea mask, and basal drag. To date, how the above affects past ice sheet evolution is unclear. Constraining the role that Pliocene regolith may have played in Pleistocene glacial cycle variability requires bounds on the amount of regolith preceding those glacial cycles. However, quantitative bounds on regolith thickness at the spatial scale of the glaciated regions of North America are currently absent in the literature. To address the above, we present an updated sediment production and transport model with dynamically calculated soft sediment mask, isostatic adjustment to dynamical sediment load and bedrock erosion, and a new subglacial hydrology model coupled to the Glacial Systems Model. The coupled model is capable of multi-million year integrations driven only by greenhouse gas concentration and insolation. The model passes a set of verification tests and conserves mass. We assess parametric sensitivity of sediment transport rates. We compare the final sediment solutions in an ensemble of whole-Pleistocene simulations for a range of initial (Pliocene) regolith thicknesses against multiple estimates for present day drift thickness distribution, Quaternary sediment volume in the Atlantic Ocean, and erosion depth estimates. Consistency of modelling and data constraints requires a Pliocene regolith thickness of less than 50 m.

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Section: Discussionmentioning

confidence: 99%