Open AccessFolding of a finite length power law layer
Author(s) -
Schmid Daniel W.,
Podladchikov Yuri Y.,
Marques Fernando O.
Publication year - 2004
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2003jb002421
Subject(s) - viscosity , aspect ratio (aeronautics) , power law , finite element method , mechanics , folding (dsp implementation) , materials science , physics , thermodynamics , mathematics , composite material , engineering , statistics , electrical engineering
Folding of an isolated finite length power law layer embedded in a Newtonian viscous matrix is investigated and compared to conventional folding experiments where the layer is of infinite length or in direct contact with lateral boundaries. The approach employed is a combination of the complex potential method for the basic state and the thin plate approximation for the linear stability analysis and is verified by finite element models. The resulting theory reveals that the aspect ratio of a layer has a first‐order influence on the development of folds. The aspect ratio competes with the effective viscosity contrast for dominant influence on the folding process. If the aspect ratio is substantially larger than the effective viscosity contrast, the conventional theories are applicable. In other situations, where the aspect ratio is smaller than the effective viscosity contrast, substantial corrections must be taken into account, which lead to a new folding mode that is mainly characterized by decreasing growth rates with increasing effective viscosity contrast (relative to the far‐field shortening rate). This new folding mode helps explain the absence of large wavelength to thickness ratio folds in nature, which may be due to the limitations of aspect ratios rather than large effective viscosity contrasts.