Bedrock surface roughness and the distribution of subglacially precipitated carbonate deposits: Implications for formation at Glacier de Tsanfleuron, Switzerland

Bryn Hubbard*, Alun Hubbard

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Citations (SciVal)

Abstract

Two carbonate deposits are identified on the exposed bedrock surface in the forefield of Glacier de Tsanfleuron, Switzerland: macrocrystalline sparite and microcrystalline micrite. Comparison of the distributions of these forms with lee-side slope facets identified by high-pass filtering of a flow-parallel bedrock profile at a range of frequencies reveals two significant results. First, while the distribution of sparite is consistent with formation in the lee side of subglacial bedrock hummocks, that of micrite is not. This contrasts with previous investigations in which both sparite and micrite have been considered to form by mineral concentration and precipitation during the refreezing of regelation-related basal meltwaters in the lee side of bedrock hummocks. Alternative mechanisms of micrite formation involving carbonate deposition and/or precipitation within subglacial bedrock hollows are proposed. Second, the distribution of sparite is most strongly correlated with the distribution of lee-side slope facets identified by filtering at a frequency equivalent to a hummock wavelength of c. 0-1 m. This correspondence indicates empirically that pressure-related melting and refreezing (regelation) operates most effectively around bedrock hummocks that are shorter than c. 0-1m,

Original languageEnglish
Pages (from-to)261-270
Number of pages10
JournalEarth Surface Processes and Landforms
Volume23
Issue number3
DOIs
Publication statusPublished - Mar 1998

Keywords

  • Bedrock roughness
  • Regelation
  • Subglacial carbonate precipitates

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