Growth, Erosion and Material Transfer in Accretionary Wedges: A Quantitative Analysis Based on Analog Modeling and the Implications for the Evolution of Convergent Margins.

Gutscher, Marc-Andre (1996) Growth, Erosion and Material Transfer in Accretionary Wedges: A Quantitative Analysis Based on Analog Modeling and the Implications for the Evolution of Convergent Margins. (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, XI, 114 pp.

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Abstract

The shallow ( < 2 km depth) structure of convergent margins can be observed at an instant in time by use of modern geophysical techniques, but the tectonic history and kinematics at depth can only be reconstructed by "forward" modeling. A quantitative analysis of the deformation processes and material transfer in thrust wedges is performed using sand as an analog material. Basal friction and material Input (vs. subducted sediment Output) were varied systematically. The influence of these two and other parameters (e.g. initial slope, backstop strength) on the stress and strain fields and on the relative fraction of frontally accreted, underplated and subducted sediment, was investigated. Basal friction and relative Input were shown to most strongly control the tectonic evolution. Low basal friction produces long thin wedges, by continuous frontal imbricate thrusting. Substantial basal erosion can occur simultaneously during wedge growth. This is true in all cases; 1 > 0, 1 = 0 and 1 < 0, whereby the net growth or erosion of the thrust wedge varies accordingly. Generally, the erosional experiments (1 < 0) build steeper wedges than the accretionary ones (1 > 0). Accretionary, low basal friction experiments grow in self-similar fashion, at the "critical taper", in good agreement with Mohr-Coulomb wedge theory. (...)

Document Type: Thesis (PhD/ Doctoral thesis)
Thesis Advisor: von Huene, Roland and Malavielle, J.
Keywords: Evolution, material transfer, analog modeling, convergent margins
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Date Deposited: 18 Nov 2021 07:51
Last Modified: 18 Nov 2021 07:51
URI: https://oceanrep.geomar.de/id/eprint/54395

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