Investigating the complex interface where bedrock transforms to regolith

S. L. Brantley, H. Buss, M. Lebedeva, R. C. Fletcher, L. Ma

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

The interface where bedrock transforms to regolith is not planar but rather has a roughness that varies with the scale of observation. The complexity of this surface is manifested in both element-depth and fragment size-depth distributions and may sometimes be related to the longitudinal profiles of watershed streams. The fractal nature of the bedrock-regolith interface means that the interface has a " thickness" which is >20. m in two ridgetop examples from Pennsylvania and Puerto Rico. Such weathering thicknesses, modeled as a function of one-dimensional fluid flow, are affected by the balance between rates of weathering and erosion. One-dimensional models are consistent with weathering advance rates that vary with equilibrium solubility and porefluid velocities (and not reaction kinetics). However, fluid flow is not strictly downward and one-dimensional. Permeability of regolith changes as particle size and bulk density changes with depth. Thus, both downward and lateral flow occurs especially at reaction fronts where reactions change permeability. The rate of weathering advance is, therefore, affected by the 3-dimensional distribution of reaction zones that affect permeability across the watershed. Quantitative models of such phenomena over a range of spatial and temporal scales are needed.

Original languageEnglish (US)
Pages (from-to)S12-S15
JournalApplied Geochemistry
Volume26
Issue numberSUPPL.
DOIs
StatePublished - Jun 1 2011

Fingerprint

regolith
Weathering
bedrock
transform
weathering
permeability
Watersheds
fluid flow
Flow of fluids
watershed
advance rate
reaction kinetics
Reaction kinetics
Fractals
bulk density
roughness
vertical distribution
Erosion
solubility
Solubility

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Pollution
  • Geochemistry and Petrology

Cite this

Brantley, S. L. ; Buss, H. ; Lebedeva, M. ; Fletcher, R. C. ; Ma, L. / Investigating the complex interface where bedrock transforms to regolith. In: Applied Geochemistry. 2011 ; Vol. 26, No. SUPPL. pp. S12-S15.
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Investigating the complex interface where bedrock transforms to regolith. / Brantley, S. L.; Buss, H.; Lebedeva, M.; Fletcher, R. C.; Ma, L.

In: Applied Geochemistry, Vol. 26, No. SUPPL., 01.06.2011, p. S12-S15.

Research output: Contribution to journalArticle

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