Fragmentation of the Farallon Plate by Pivoting Subduction

Menard, H. W.

doi:10.1086/649658

Cited by 149 publications

(99 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Larter and Barker [1] suggest that the Phoenix plate may be an example of 'pivoting subduction' [23]: they hypothesise a larger slab pull force in the northeast of the plate, where the subducting lithosphere was much older than in the southwest, that created a couple to rotate it about a point to the southwest. Those authors calculated a stage pole for the interval C6A^C5C (V21^16.5 Ma) that is indeed in such a position (Fig.…”

Section: Discussionmentioning

confidence: 99%

Tectonic evolution of the Antarctic–Phoenix plate system since 15 Ma

Eagles

2004

Earth and Planetary Science Letters

View full text Add to dashboard Cite

Joint inversion of magnetic isochron and fracture zone data from the extinct Antarctic^Phoenix spreading system in SW Drake Passage yields seven new finite reconstruction poles. The inversion results are very well constrained for such a short length of plate boundary. Although this is partly because the finite poles are located close to the reconstructed region, the optimum use of fracture zone identifications from satellite-derived free-air gravity data is also important^as the stability of stage poles throughout the short intervals in the model affirms. The model results describe a well-organised spreading system since magnetic anomaly chron C5AD (V15 Ma) in which the Phoenix plate rotated about stage poles nearby to the southwest. Stage pole locations are broadly consistent with a hypothesis of pivoting subduction as the driving force of Phoenix plate movement, and there is some evidence in the progression of stage poles for late stage movement of the subduction pivot in response to the changing azimuth of the subduction zone at which the Phoenix plate was being consumed. The model kinematics alone provide no unequivocal support for previous interpretations of disruption of the subducted part of the Phoenix plate. The very latest stages of spreading saw falling spreading rates between magnetic anomaly chrons C4 (V8.1 Ma) and C2A (V3.3 Ma) when the Antarctic^Phoenix Ridge became extinct. This is consistent with an increase in shear stress across the plate bounding Shackleton Fracture Zone due to a plate reorganisation in the neighbouring Scotia Sea following the cessation of spreading on the West Scotia Ridge. ß

show abstract

Section: Discussionmentioning

confidence: 99%

Tectonic evolution of the Antarctic–Phoenix plate system since 15 Ma

Eagles

2004

Earth and Planetary Science Letters

View full text Add to dashboard Cite

show abstract

“…The overriding plate appears to be in an overall state of extension rather than compression (SINGH and PARDO, 1993), which is counterintuitive when considering the compressive forces associated with the subduction collision and the traction of an underplated slab (DE FRANCO et al, 2007;KEPPIE, 2009;MORAN-ZENTENO et al, 2007;NIETO-SAMANIEGO et al, 2006). The trans-Mexican Volcanic Belt has embayments along the landward projection of the Rivera, Orozoco, and Clipperton fracture zones suggesting that the Cocos plate is being further divided into smaller plates by tearing of the slab (BLATTER et al, 2007;MENARD, 1978). The breakup of the Cocos plate allows the smaller fragments to rollback faster and results in the along trench dip variation (BILLEN, 2008).…”

Section: Current State Of Subduction In Central Mexicomentioning

confidence: 99%

An Evaluation of Proposed Mechanisms of Slab Flattening in Central Mexico

Skinner

Clayton

2010

Pure Appl. Geophys.

View full text Add to dashboard Cite

Abstract-Central Mexico is the site of an enigmatic zone of flat subduction. The general geometry of the subducting slab has been known for some time and is characterized by a horizontal zone bounded on either side by two moderately dipping sections. We systematically evaluate proposed hypotheses for shallow subduction in Mexico based on the spatial and temporal evidence, and we find no simple or obvious explanation for the shallow subduction in Mexico. We are unable to locate an oceanic lithosphere impactor, or the conjugate of an impactor, that is most often called upon to explain shallow subduction zones as in South America, Japan, and Laramide deformation in the US. The only bathymetric feature that is of the right age and in the correct position on the conjugate plate is a set of unnamed seamounts that are too small to have a significant effect on the buoyancy of the slab. The only candidate that we cannot dismiss is a change in the dynamics of subduction through a change in wedge viscosity, possibly caused by water brought in by the slab.

show abstract

“…On the earth, oceanic lithosphere with seafloor as young as 10 m.y. is subducted [Menard, 1978], yet such lithosphere is certainly less negatively buoyant than unsubducted oceanic lithosphere 150 m.y. old.…”

Section: Venus Heat Flowmentioning

confidence: 99%

Mechanisms for lithospheric heat transport on Venus: Implications for tectonic style and volcanism

Solomon¹,

Head²

1982

J. Geophys. Res.

153

View full text Add to dashboard Cite

The tectonic and volcanic characteristics of the surface of Venus are poorly known, but these characteristics must be closely related to the mechanism by which Venus rids itself of internal heat. On the other solid planets and satellites of the solar system, lithospheric heat [ransport is dominated by one of three mechanisms: (1) plate recycling, (2) lithospheric conduction, and (3) hot spot volcanism. We evaluate each mechanism as a candidate for the dominant mode of lithospheric heat transfer on Venus, and we explore the implications of each mechanism for the interpretation of Venus surface features. Despite claims made to the contrary in the literature, plate recycling on Venus cannot be excluded on the basis of either theoretical arguments or present observations on topography and radar backscatter. Landforms resulting from plate convergence and divergence on Venus would differ substantially from those on the earth because of the high surface temperature and the absence of oceans on Venus, the lack of free or hydrated water in subducted material, the possibility that subduction would more commonly be accompanied by lithospheric delamination, and the rapid spreading rates that would be required if plate recycling removes a significant fraction of the internal heat. If plate recycling occurs on Venus, the rolling plains and lowlands provinces would be approximate analogs to terrestrial ocean basins in terms of age, igneous rock type, and formative process; highlands on Venus would be roughly analogous to terrestrial continents. The hypothesis that lithospheric conduction dominates shallow heat transfer on Venus leads to the prediction that the lithosphere is thin. If Venus has a global heat loss per mass equal to that for earth, then temperatures marking the base of the thermal lithosphere on earth would be reached on Venus at an average depth of about 40 km. Unless the mantle convective planform can maintain lithospheric regions of persistently low heat flow or unless the present atmospheric greenhouse on Venus is geologically recent, then such a lithospheric thickness leads to the conclusion that the topographic features contributing to the 13 km of relief on the planet must be geologically young. The hypothesis that hot spot volcanism dominates lithospheric heat transfer on Venus leads to the prediction that the surface must be covered with numerous active volcanic sources. In particular, if a typical Venus hot spot has a volcanic flux equal to the average flux for the Hawaiian hot spot for the last 40 m.y., then 10 '• such hot spots are necessary to remove the Venus internal heat by volcanism. Such a number would produce enough volcanic material to resurface the entire planet to a depth of 1 km every 2 m.y.; few areas of the planet would escape resurfacing for geologically long periods of time. We find that none of the mechanisms for lithospheric heat transfer on Venus can be excluded as unimportant at present; it is likely that, as on earth, a combination of mechanisms operates on Venus. The strongest con...

show abstract

Fragmentation of the Farallon Plate by Pivoting Subduction

Cited by 149 publications

References 20 publications

Tectonic evolution of the Antarctic–Phoenix plate system since 15 Ma

Tectonic evolution of the Antarctic–Phoenix plate system since 15 Ma

An Evaluation of Proposed Mechanisms of Slab Flattening in Central Mexico

Mechanisms for lithospheric heat transport on Venus: Implications for tectonic style and volcanism

Contact Info

Product

Resources

About