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The role of lateral strength contrasts in orogenesis: A 2D numerical study.
- Source :
-
Tectonophysics . Oct2018, Vol. 746, p549-561. 13p. - Publication Year :
- 2018
-
Abstract
- Abstract In this paper we present a series of thermo-mechanical experiments on continent-continent collision zones to investigate the role of lateral strength contrasts in terms of collision dynamics and orogen geometries. Our results show that differences in crustal rheology, may lead to a variety of different patterns of deformation and crustal geometries. Upper plate indentation forms a sequence of foreland propagating thrust units made of brittle upper crust on the lower plate. The strong deformation of the lower plate stands in stark contrast to the undeformed upper plate. In contrast, subduction of strong lithosphere beneath a weak upper plate forms a complex pattern of deformation. Deformation initiates on the lower plate and forms an antiformal stack made of brittle upper crust, before it indents the upper plate. Hence, deformation is present on both, the lower and upper plate, despite differences in initial strength. The outcome of this study has direct implications to natural collision zones, where differences in strength between the upper and lower plate exist. For example, along strike variability of upper vs. lower plate shortening in the Alps are likely to be controlled by contrasts in crustal strength. Furthermore, we suggest that the antiformal stack in the axial zone of the Pyrenees might indicate a strong lower plate at the onset of collision. Our results may therefore provide important constraints for the rheological state of continents during collision. Graphical abstract Image 1 Highlights • We study influences of crustal strength contrasts on continent-continent collision. • Crustal deformation always migrates from the stronger into the weaker plate with time. • Large-scale mountain geometries are controlled by crustal strength variations. [ABSTRACT FROM AUTHOR]
- Subjects :
- *OROGENY
*CRUST of the earth
*NEWTONIAN fluids
*NUMERICAL analysis
*RHEOLOGY
Subjects
Details
- Language :
- English
- ISSN :
- 00401951
- Volume :
- 746
- Database :
- Academic Search Index
- Journal :
- Tectonophysics
- Publication Type :
- Academic Journal
- Accession number :
- 133169845
- Full Text :
- https://doi.org/10.1016/j.tecto.2017.08.010