Simplified model of oblique subduction. The oblique subduction motion is composed of motion vectors that are parallel and orthogonal to plate boundary.[1] The obliquity of plate convergence is compensated by the relative motion between forearc sliver and the remaining overriding plate.[1] In this way, the relative motion between the overriding plate and the subducting plate is almost perpendicular to the plate boundary.[1] Adapted from Westbrook, 2005.[1]
Oblique subduction is a form of subduction (i.e. a tectonic process involving the convergence of two plates where the denser plate descends into Earth's interior)[2] for which the convergence direction differs from 90° to the plate boundary.[3] Most convergent boundaries involve oblique subduction,[3] particularly in the Ring of Fire including the Ryukyu, Aleutian, Central America and Chile subduction zones.[4] In general, the obliquity angle is between 15° and 30°.[5] Subduction zones with high obliquity angles include Sunda trench (ca. 60°) and Ryukyu arc (ca. 50°).[5]
Obliquity in plate convergence causes differences in dipping angle and subduction velocity along the plate boundary.[6][7] Tectonic processes including slab roll-back, trench retreat (i.e. a tectonic response to the process of slab roll-back that moves the trench seaward)[8] and slab fold (i.e. buckling of subducting slab due to phase transition)[9] may also occur.[6][7]
Moreover, collision of two plates leads to strike slip deformation of the forearc, thus forming a series of features including forearc slivers and strike slip fault systems that are sub-parallel to ocean trenches.[10] In addition, oblique subduction is associated with the closure of ancient ocean, tsunami and block rotations in several regions.[11][12][13]
^ abcdWestbrook, G. K. (2005-01-01), "TECTONICS | Convergent Plate Boundaries and Accretionary Wedges", in Selley, Richard C.; Cocks, L. Robin M.; Plimer, Ian R. (eds.), Encyclopedia of Geology, Oxford: Elsevier, pp. 307–317, doi:10.1016/b0-12-369396-9/00456-1, ISBN 978-0-12-369396-9, retrieved 2021-11-11
^Introduction to Mineralogy and Petrology. 2020. doi:10.1016/c2019-0-00625-5. ISBN 9780128205853. S2CID 242138731.
^ abBalázs, Attila; Faccenna, Claudio; Ueda, Kosuke; Funiciello, Francesca; Boutoux, Alexandre; Blanc, Eric J. -P.; Gerya, Taras (2021-09-01). "Oblique subduction and mantle flow control on upper plate deformation: 3D geodynamic modeling". Earth and Planetary Science Letters. 569: 117056. Bibcode:2021E&PSL.56917056B. doi:10.1016/j.epsl.2021.117056. hdl:20.500.11850/491584. ISSN 0012-821X.
^Kimura, Gaku (1986-05-01). "Oblique subduction and collision: Forearc tectonics of the Kuril arc". Geology. 14 (5): 404–407. Bibcode:1986Geo....14..404K. doi:10.1130/0091-7613(1986)14<404:OSACFT>2.0.CO;2. hdl:10126/4513. ISSN 0091-7613.
^ abArgus, Donald F.; Gordon, Richard G.; DeMets, Charles (November 2011). "Geologically current motion of 56 plates relative to the no-net-rotation reference frame: NNR-MORVEL56". Geochemistry, Geophysics, Geosystems. 12 (11): n/a. Bibcode:2011GGG....1211001A. doi:10.1029/2011GC003751.
^ abCerpa, Nestor G.; Araya, Rodolfo; Gerbault, Muriel; Hassani, Riad (2015). "Relationship between slab dip and topography segmentation in an oblique subduction zone: Insights from numerical modeling". Geophysical Research Letters. 42 (14): 5786–5795. Bibcode:2015GeoRL..42.5786C. doi:10.1002/2015GL064047. ISSN 1944-8007. S2CID 128791885.
^ abBalázs, Attila; Faccenna, Claudio; Ueda, Kosuke; Funiciello, Francesca; Boutoux, Alexandre; Blanc, Eric J. -P.; Gerya, Taras (2021-09-01). "Oblique subduction and mantle flow control on upper plate deformation: 3D geodynamic modeling". Earth and Planetary Science Letters. 569: 117056. Bibcode:2021E&PSL.56917056B. doi:10.1016/j.epsl.2021.117056. hdl:20.500.11850/491584. ISSN 0012-821X.
^Niu, Yaoling (2018-05-01). "Geological understanding of plate tectonics: Basic concepts, illustrations, examples and new perspectives". Global Tectonics and Metallogeny. 10: 23–46. doi:10.1127/gtm/2014/0009.
^Billen, Magali I. (2020). "Deep slab seismicity limited by rate of deformation in the transition zone". Science Advances. 6 (22): eaaz7692. Bibcode:2020SciA....6.7692B. doi:10.1126/sciadv.aaz7692. PMC 7385466. PMID 32766442.
^Fitch, Thomas J. (1972-08-10). "Plate convergence, transcurrent faults, and internal deformation adjacent to Southeast Asia and the western Pacific". Journal of Geophysical Research. 77 (23): 4432–4460. Bibcode:1972JGR....77.4432F. doi:10.1029/JB077i023p04432. hdl:2060/19720023718.
^Cite error: The named reference :23 was invoked but never defined (see the help page).
^Wallace, Laura M.; Beavan, John; McCaffrey, Robert; Darby, Desmond (2004). "Subduction zone coupling and tectonic block rotations in the North Island, New Zealand". Journal of Geophysical Research: Solid Earth. 109 (B12). Bibcode:2004JGRB..10912406W. doi:10.1029/2004JB003241. ISSN 2156-2202.
^Cite error: The named reference :16 was invoked but never defined (see the help page).
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