Folding in a Cooling Crust with Elasto-visco-plastic Rheology: An Example from Venus

Details Folding in a Cooling Crust with Elasto-visco-plastic Rheology: An Example from Venus Folding in a Cooling Crust with Elasto-visco-plastic Rheology: An Example from Venus

Dec 2001

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001agufm.t41b0865g&link_type=abstract

American Geophysical Union, Fall Meeting 2001, abstract #T41B-0865

Mathematics

Logic

3210 Modeling, 5475 Tectonics (8149), 6295 Venus, 8005 Folds And Folding, 8159 Rheology: Crust And Lithosphere

Scientific paper

We investigate the effects of simultaneous shortening and cooling on fold wavelengths in a crust with elasto-visco-plastic (EVP) rheology, in order to better understand the interplay between rates of shortening and cooling on the anelastic response of the crust. We apply our techniques to Venusian crustal plateaus, which show ubiquitous, low-amplitude folds with a continuous range of wavelengths from < 100 m to > 30 km. Previous studies have proposed that these folds (and other characteristic crustal plateau structures) originated during crustal plateau formation by interaction of large mantle plumes with the surface during a time of globally thin lithosphere [1]. In this scenario, a plume arriving at the lithosphere erases existing structures and produces a mechanically homogeneous surface by heating and/or melting the crust. Subsequent cooling results in a surface layer that is capable of recording strains and that thickens with time. We investigate the conditions under which folds matching those observed in Venusian crustal plateaus are created in a finite element model simulating concurrent shortening and cooling, as motivated by the tectonic scenario in [1]. Our models are novel because a) the EVP rheology more accurately represents the actual crust than viscous or viscoelastic models; and b) other models generally specify a priori a folding layer thickness and geometry, with material properties different from those of the surrounding rock, and this pre-determines the resulting fold wavelength(s). By contrast, our models incorporate spatially uniform material properties but temperature-dependent rheology [2], so that the strength profile through the crust evolves with cooling. This allows the thermal and stress conditions to determine the instantaneous effective folding layer thickness at each time step, which in turn determines surface fold wavelengths. We investigate conditions under which short wavelength folds are initiated when the effective folding layer is very thin, and the fold wavelength increases with cooling and the resultant increase in layer thickness. This progression requires a rather specific set of conditions, and most notably may place constraints on the shortening rate, surface temperature, and thermal gradient during folding. [1] Phillips, R.J. and V.L. Hansen 1998. Geological evolution of Venus: A geodynamical and magmatic framework. Science, 279,1492-1497. [2] Mackwell, S.J., M.E. Zimmerman and D.L. Kohlstedt 1998. High-temperature deformation of dry diabase with application to tectonics on Venus. JGR 103, 975-984.

Affiliated with

Also associated with

No associations

Rating

Folding in a Cooling Crust with Elasto-visco-plastic Rheology: An Example from Venus does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Folding in a Cooling Crust with Elasto-visco-plastic Rheology: An Example from Venus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Folding in a Cooling Crust with Elasto-visco-plastic Rheology: An Example from Venus will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1239959