Deformation from the convergence of oceanic lithosphere into Yap trench and its implications for early-stage subduction

Lee, Sang-Mook

doi:10.1016/j.jog.2003.10.003

Cited by 58 publications

(43 citation statements)

References 33 publications

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“…Metamorphic rocks in the greenschist phase together with the positive gravity anomaly suggest active uplift. Finally, the Yap Trench is perfectly aligned with the extinct spreading center on the East Philippine basin and associated fracture zones ( Figure 2b) and supports the hypothesis that new trenches form at preexisting structures [Lee, 2004].…”

Section: Early Stage Systemssupporting

confidence: 76%

“…There are some incipient margins, all forced, that are so young we do not know if they are going to develop into fully fledged subduction zones, including the Gorringe Bank (N. Atlantic), the Owen Ridge (Arabian Sea) [ Massell et al , 2000], the Mussau Trench on the eastern boundary of the Caroline plate [ Hegarty et al , 1982], and the Yap Trench on the western boundary of the Caroline plate [ Lee , 2004].…”

Section: Observational Record Of Subduction Initiationmentioning

confidence: 99%

“…The Yap Trench (Y, Figure 2b) south of the Marianas may be an example of early stage subduction [ Lee , 2004]. Although seismically active this system does not have a Benioff zone but has a trench and island arc; the lack of sediments within the trench suggest active subduction today [ Fujiwara et al , 2000; Lee , 2004]. The Yap is distinctly different from well developed subduction zones with its short trench‐arc distance (∼50 km) and narrow trench (∼50 km) [ Lee , 2004].…”

Section: Observational Record Of Subduction Initiationmentioning

confidence: 99%

“…Although seismically active this system does not have a Benioff zone but has a trench and island arc; the lack of sediments within the trench suggest active subduction today [ Fujiwara et al , 2000; Lee , 2004]. The Yap is distinctly different from well developed subduction zones with its short trench‐arc distance (∼50 km) and narrow trench (∼50 km) [ Lee , 2004]. Moreover, neither the island arc nor the inner trench wall are volcanically active, rather they are composed of metamorphic rocks, including ultramafic schists [ Hawkins and Batiza , 1977].…”

Section: Observational Record Of Subduction Initiationmentioning

confidence: 99%

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Evolving force balance during incipient subduction

Gurnis

Hall

Lavier

2004

Geochem Geophys Geosyst

399

552

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[1] Nearly half of all active subduction zones initiated during the Cenozoic. All subduction zones associated with active back arc extension have initiated since the Eocene, hinting that back arc extension may be intimately associated with an interval (several tens of Myr) following subduction initiation. That such a large proportion of subduction zones are young indicates that subduction initiation is a continuous process in which the net resisting force associated with forming a new subduction zone can be overcome during the normal evolution of plates. Subduction initiation is known to have occurred in a variety of tectonic settings: old fracture zones, transform faults, and extinct spreading centers and through polarity reversal behind active subduction zones. Although occurring within different tectonic settings, four known subduction initiation events (Izu-Bonin-Mariana (IBM) along a fracture zone, Tonga-Kermadec along an extinct subduction boundary, New Hebrides within a back arc, and Puysegur-Fiordland along a spreading center) were typified by rapid uplift within the forearc followed by sudden subsidence. Other constraints corroborate the compressive nature of IBM and Tonga-Kermadec during initiation. Using an explicit finite element method within a two-dimensional domain, we explore the evolving force balance during initiation in which elastic flexure, viscous flow, plastic failure, and heat transport are all considered. In order to tie theory with observation, known tectonic settings of subduction initiation are used as initial and boundary conditions. We systematically explore incipient compression of a homogeneous plate, a former spreading center, and a fracture zone. The force balance is typified by a rapid growth in resisting force as the plate begins bending, reaching a maximum value dependent on plate thickness, but typically ranging from 2 to 3 Â 10 12 N/m for cases that become self-sustaining. This is followed by a drop in stress once a shear zone extends through the plate. The formation of a throughgoing fault is associated with rapid uplift on the hanging wall and subsidence on the footwall. Cumulative convergence, not the rate of convergence, is the dominant control on the force balance. Viscous tractions influence the force balance only if the viscosity of the asthenosphere is >10 20 Pa s, and then only after plate failure. Following plate failure, buoyancy of the oceanic crust leads to a linear increase with crustal thickness in the work required to initiate subduction. The total work done is also influenced by the rate of lithospheric failure. A self-sustaining subduction zone does not form from a homogeneous plate. A ridge placed under compression localizes subduction initiation, but the resisting ridge push force is not nearly as large as the force required to bend the subducting plate. The large initial bending resistance can be entirely eliminated in ridge models, explaining the propensity for new subduction zones to form through polarity reversals. A fracture zone (FZ) placed in comp...

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Section: Early Stage Systemssupporting

confidence: 76%

Section: Observational Record Of Subduction Initiationmentioning

confidence: 99%

Section: Observational Record Of Subduction Initiationmentioning

confidence: 99%

Section: Observational Record Of Subduction Initiationmentioning

confidence: 99%

See 2 more Smart Citations

Evolving force balance during incipient subduction

Gurnis

Hall

Lavier

2004

Geochem Geophys Geosyst

399

552

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“…The Yap Trench is one of the deepest trenches on Earth, with a deepest water depth of 8527 m [20]. The subduction processes, magmatism, and tectonic activity of the Yap Trench have been studied to investigate the dynamic mechanisms and mantle evolution of the Yap subduction system [20][21][22][23][24][25][26][27]. The results have shown that the Yap Trench has some features in common with other subduction zones in the western Pacific, such as a trench-arc-basin system and a great axial depth [22,23].…”

Section: Geological Settingmentioning

confidence: 99%

Ancient Melt Depletion and Metasomatic History of the Subduction Zone Mantle: Osmium Isotope Evidence of Peridotites from the Yap Trench, Western Pacific

Chen

Tang

et al. 2019

Minerals

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Highly depleted peridotites from the Yap Trench in the western Pacific Ocean have been studied for Re-Os elements and Re-Os isotopes. These peridotites have a low Re-Os content and variable 187Os/188Os ratios (0.12043–0.14867). The highest 187Os/188Os ratio is far higher than that of the primitive upper mantle and the lowest 187Os/188Os ratio is comparable to the most unradiogenic 187Os/188Os ratio (0.11933) discovered in subduction zone peridotites. The suprachondritic 187Os/188Os ratios of the Yap Trench peridotites results from modification of the mantle wedge by slab-derived fluid and melt. This is consistent with the observation that high 187Os/188Os ratios generally occur in oceanic peridotites with low Os content (<2 ppb) since Os may be reduced during late processes such as fluid alteration and melt refertilization. The sub-chondritic 187Os/188Os ratios of the Yap Trench peridotites correspond to a Re depletion age of 0.24–1.16 billion years, which means that these peridotites represent old mantle residue of ancient melting events. This ancient melting, combined with probable back-arc melting and forearc melting during subduction initiation, indicates that the Yap Trench mantle has a complex evolutionary history. The amount of old mantle residue in the oceanic asthenosphere was underestimated because the 187Os/188Os ratio in mantle peridotites is elevated during late processes. Therefore, old depleted mantle fragments may contribute substantially to the chemical heterogeneity of the oceanic mantle.

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Formation mechanism of the moniliform seamounts outside the West Melanesian Trench

Zhang

Tian

et al. 2017

Geological Journal

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Our study on the seamounts in the southeast Caroline Plate reveals a formation of a special kind of seamounts in the oceanic basin. These moniliform seamounts link up like the reason of hotspots, but the tectonic factors lead to their formation. The differential motions of the Caroline, North Bismarck, and Pacific plates resulted in the shear stress field by the West Melanesian Trench. The R and R′ faults can be distinguished obviously by seafloor topography. The evolution history of these seamounts can be subdivided into two stages as follows. (a) The R′ faults developed firstly as normal faults to generate ridges on these faults as the release of the underlying sediments. (b) The R faults appeared as shear faults and cut off the ridge from the older R′ faults. These faults can be very deep fractures, which cut through the lithosphere and produced a NW‐trending negative anomaly in isostatic gravity anomaly. As the pressure is released by the R faults, the sediments releasing under the R faults accumulated into these seamounts. The other sections of the R faults performed like a valley because of the leakage of sediments along the faults. Sediments would also release along the R faults to generate ridges when no seamount occurs on the faults.

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Deformation from the convergence of oceanic lithosphere into Yap trench and its implications for early-stage subduction

Cited by 58 publications

References 33 publications

Evolving force balance during incipient subduction

Evolving force balance during incipient subduction

Ancient Melt Depletion and Metasomatic History of the Subduction Zone Mantle: Osmium Isotope Evidence of Peridotites from the Yap Trench, Western Pacific

Formation mechanism of the moniliform seamounts outside the West Melanesian Trench

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