Details
| Original language | English |
|---|---|
| Pages (from-to) | 1769-1791 |
| Number of pages | 23 |
| Journal | TECTONICS |
| Volume | 34 |
| Issue number | 9 |
| Publication status | Published - 1 Sept 2015 |
Abstract
Subduction of aseismic oceanic ridges causes considerable uplift and deformation of the upper plate and may lead, for example, to the indentation of the forearc, the formation of marine terraces, or distinct fault patterns in the upper plate. Depending on the orientation of the ridge relative to the plate convergence direction, the ridge may either be stationary or migrate along the margin. Here we use three-dimensional numerical models to investigate the tectonic evolution of forearcs affected by ridge subduction. In different experiments, we distinguish between migrating/non-migrating ridges and accretive/erosive margins, respectively. Our results reveal that displacement and strain fields above migrating and non-migrating ridges are asymmetric with respect to the ridge axis unless both ridge and plate convergence direction are perpendicular to the trench. As the asymmetric deformation pattern shifts along the margin through time, uplift caused by the underthrusting ridge is followed by subsidence when the ridge crest passed by, and regions initially experiencing shortening may subsequently undergo extension and vice versa. If the forearc comprises an accretionary prism, the ridge-induced reentrant is larger than those in models with erosive forearcs and strain localizes in the frontal part of the wedge. Additional models with a setup adjusted to the Cocos and Gagua Ridges provide constraints on the onset of their subduction at the Central American and Ryukyu margins at ~2Ma and 1Ma, respectively. Displacement and strain fields from a model for the Nazca Ridge collision zone show good agreement with geological data from marine terraces and Quaternary faulting.
Keywords
- 3D finite-element modeling, Cocos Ridge, forearc deformation, Gagua Ridge, Nazca Ridge, oblique aseismic ridge subduction
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geophysics
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
Sustainable Development Goals
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In: TECTONICS, Vol. 34, No. 9, 01.09.2015, p. 1769-1791.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Deformation of erosive and accretive forearcs during subduction of migrating and non-migrating aseismic ridges
T2 - Results from 3-D finite element models and application to the Central American, Peruvian, and Ryukyu margins
AU - Zeumann, Stefanie
AU - Hampel, Andrea
PY - 2015/9/1
Y1 - 2015/9/1
N2 - Subduction of aseismic oceanic ridges causes considerable uplift and deformation of the upper plate and may lead, for example, to the indentation of the forearc, the formation of marine terraces, or distinct fault patterns in the upper plate. Depending on the orientation of the ridge relative to the plate convergence direction, the ridge may either be stationary or migrate along the margin. Here we use three-dimensional numerical models to investigate the tectonic evolution of forearcs affected by ridge subduction. In different experiments, we distinguish between migrating/non-migrating ridges and accretive/erosive margins, respectively. Our results reveal that displacement and strain fields above migrating and non-migrating ridges are asymmetric with respect to the ridge axis unless both ridge and plate convergence direction are perpendicular to the trench. As the asymmetric deformation pattern shifts along the margin through time, uplift caused by the underthrusting ridge is followed by subsidence when the ridge crest passed by, and regions initially experiencing shortening may subsequently undergo extension and vice versa. If the forearc comprises an accretionary prism, the ridge-induced reentrant is larger than those in models with erosive forearcs and strain localizes in the frontal part of the wedge. Additional models with a setup adjusted to the Cocos and Gagua Ridges provide constraints on the onset of their subduction at the Central American and Ryukyu margins at ~2Ma and 1Ma, respectively. Displacement and strain fields from a model for the Nazca Ridge collision zone show good agreement with geological data from marine terraces and Quaternary faulting.
AB - Subduction of aseismic oceanic ridges causes considerable uplift and deformation of the upper plate and may lead, for example, to the indentation of the forearc, the formation of marine terraces, or distinct fault patterns in the upper plate. Depending on the orientation of the ridge relative to the plate convergence direction, the ridge may either be stationary or migrate along the margin. Here we use three-dimensional numerical models to investigate the tectonic evolution of forearcs affected by ridge subduction. In different experiments, we distinguish between migrating/non-migrating ridges and accretive/erosive margins, respectively. Our results reveal that displacement and strain fields above migrating and non-migrating ridges are asymmetric with respect to the ridge axis unless both ridge and plate convergence direction are perpendicular to the trench. As the asymmetric deformation pattern shifts along the margin through time, uplift caused by the underthrusting ridge is followed by subsidence when the ridge crest passed by, and regions initially experiencing shortening may subsequently undergo extension and vice versa. If the forearc comprises an accretionary prism, the ridge-induced reentrant is larger than those in models with erosive forearcs and strain localizes in the frontal part of the wedge. Additional models with a setup adjusted to the Cocos and Gagua Ridges provide constraints on the onset of their subduction at the Central American and Ryukyu margins at ~2Ma and 1Ma, respectively. Displacement and strain fields from a model for the Nazca Ridge collision zone show good agreement with geological data from marine terraces and Quaternary faulting.
KW - 3D finite-element modeling
KW - Cocos Ridge
KW - forearc deformation
KW - Gagua Ridge
KW - Nazca Ridge
KW - oblique aseismic ridge subduction
UR - http://www.scopus.com/inward/record.url?scp=84945473936&partnerID=8YFLogxK
U2 - 10.1002/2015TC003867
DO - 10.1002/2015TC003867
M3 - Article
AN - SCOPUS:84945473936
VL - 34
SP - 1769
EP - 1791
JO - TECTONICS
JF - TECTONICS
SN - 0278-7407
IS - 9
ER -