- Title
- Initiation of subduction along oceanic transform faults: Insights from three-dimensional analogue modeling experiments
- Creator
- Boutelier, David; Beckett, David
- Relation
- Frontiers in Earth Science Vol. 6, no. 204
- Publisher Link
- http://dx.doi.org/10.3389/feart.2018.00204
- Publisher
- Frontiers Research Foundation
- Resource Type
- journal article
- Date
- 2018
- Description
- Three-dimensional analog experiments are employed to explore how self-sustaining subduction may initiate along an oceanic transform fault. The models include a realistic spatial distribution of plate thickness, strength, and buoyancy of the lithosphere near an oceanic transform fault characteristic of the spreading rate. Convergence is imposed across the transform fault and strain in the model lithosphere is quantified using a surface Particle Imaging Velocimetry system. A force sensor is employed to defined when a self-sustaining subduction regime is generated. Cylindrical experiments reveal that subduction polarity is controlled by the buoyancy gradient and the strengths of the plates. With no inclined weak zones, imposed orthogonal compression results in the nucleation of a new fault in the weakest plate leading to the young and positively buoyant plate subducting. However, with an inclined weak zone, the buoyancy contrast controls subduction polarity with the most negatively buoyant plate subducting and a self-sustaining subduction regime obtained after ~300 km of imposed shortening. This situation is obtained when including an inverted triangular weak zone on top of the transform fault associated with the serpentinization of the crust and mantle. In non-cylindrical experiments, taking into account the change along strike of plate strength and buoyancy, the capacity of the transform fault to generate a self-sustaining subduction regime is greatly reduced. Subduction initiates simultaneously with opposite polarity at the two extremities of the transform segment and, at depth, a lithospheric tear is produced that separates the two subducting slabs. In the center of the transform fault, the lack of buoyancy or strength contrast between the two plates leads to multiple thrusts with variable polarities, overlapping each other, and each accommodating too little shortening to become the new plate boundary. This indicates that additional mechanical work is required in the center of the transform fault which prevents the establishment of a self-sustaining subduction regime.
- Subject
- analog modeling; subduction; subduction initiation; oceanic fault; serpentinization; buoyancy; lithosphere
- Identifier
- http://hdl.handle.net/1959.13/1412082
- Identifier
- uon:36426
- Identifier
- ISSN:2296-6463
- Rights
- © 2018 Boutelier and Beckett. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
- Language
- eng
- Full Text
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