DMCA
Is plane-strain a valid assumption in noncylindrical fault-cored folds (2007)
| Venue: | Journal of Structural Geology |
| Citations: | 3 - 1 self |
BibTeX
@ARTICLE{Shackleton07isplane-strain,
author = {J. Ryan Shackleton and Michele L. Cooke},
title = {Is plane-strain a valid assumption in noncylindrical fault-cored folds},
journal = {Journal of Structural Geology},
year = {2007}
}
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Abstract
Many algorithms assume plane strain to construct, model and restore fault-cored folds. Using mechanical models that allow heterogeneous transport in three dimensions, we explore the distribution and magnitude of out-of-plane transport in plunging fault-cored anticlines and provide guidelines of where plane strain should and should not be applied. We developed a new technique of incrementing infinitesimal elastic strains to produce folds with aspect ratios similar to natural folds. Map views of displacement vectors show that in general, out-of-plane displacement is localized near the lateral fold tips. Cross-sections show that out-of-plane transport is depth dependent with out-of-plane displacement increasing toward the surface. Flexural slip surfaces compartmentalize out-of-plane transport within distinct mechanical units, with the maximum out-of-plane displacement near the tops of mechanical units. Two-dimensional models with additional frictionally slipping bed contacts suggest that freely slipping contacts can approximate the deformation of many frictionally slipping contacts. We show that out-of-plane transport is significant in the simplest non-cylindrical folds, and suggest that complex non-cylindrical structures should not be modeled using plane strain exclusively. We also show that flexural slip surfaces exert a significant control on the magnitude and structural position of out-of-plane transport in our models.
Keyphrases
out-of-plane transport valid assumption plane strain noncylindrical fault-cored fold out-of-plane displacement flexural slip surface fault-cored fold complex non-cylindrical structure lateral fold tip infinitesimal elastic strain distinct mechanical unit map view mechanical model two-dimensional model significant control mechanical unit natural fold structural position maximum out-of-plane displacement many algorithm displacement vector aspect ratio non-cylindrical fold fault-cored anticlines heterogeneous transport bed contact new technique
