Subglacial bed form morphology controlled by ice speed and sediment thickness

Subglacial bed forms (drumlins, ribbed moraines, and megascale glacial lineations) are enigmatic repetitive flow-parallel and flow-transverse landforms common in glaciated landscapes. Their evolution and morphology are a potentially powerful constraint for ice sheet modeling, but there is little consensus on bed form dynamics or formative mechanisms. Here we explore shallow sediment bed form dynamics via a simple model that iterates (i) down-flow till flux, (ii) pressure gradient-driven till flux, and (iii) entrainment and deposition of sediment. Under various boundary conditions, replicas of subglacial bed forms readily emerge. Bed form dynamics mirror those in subaqueous and aeolian domains. Transitions between ribbed moraines and elongate flow-parallel bed forms are associated with increasing ice speeds and declining sediment thickness. These simulations provide quantitative flux estimates and suggest that widely observed transitions in shallow sediment subglacial bed forms (e.g., ribbed moraines to drumlinoids to megascale glacial lineations) are manifestations of subtle variations in ice velocity and sediment thickness.

Dowling, Thomas P FLund University,Lunds universitet,Kvartärgeologi,Geologiska institutionen,Naturvetenskapliga fakulteten,Quaternary Sciences,Department of Geology,Faculty of Science(Swepub:lu)geol-tdi (författare)
Stokes, Chris R.Durham University (författare)
Hugenholtz, Chris H.University of Calgary (författare)
University of CalgaryKvartärgeologi (creator_code:org_t)

Av författaren/redakt...: Barchyn, Thomas ...; Dowling, Thomas ...; Stokes, Chris R.; Hugenholtz, Chri ...

Om ämnet

NATURVETENSKAP: NATURVETENSKAP; och Geovetenskap och ...; och Multidisciplinär ...

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.