# Folding of a finite length power law layer

## Détails

ID Serval

serval:BIB_4E50F220A5A1

Type

**Article**: article d'un périodique ou d'un magazine.

Collection

Publications

Institution

Titre

Folding of a finite length power law layer

Périodique

Journal of Geophysical Research - Solid Earth

ISSN-L

0148-0227

Statut éditorial

Publié

Date de publication

2004

Peer-reviewed

Oui

Volume

109

Pages

B03407

Langue

anglais

Résumé

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.

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.

Open Access

Oui

Création de la notice

09/10/2012 19:50

Dernière modification de la notice

20/08/2019 14:03