The structure of Cretaceous oceanic crust of the NW Pacific: Constraints on processes at fast spreading centers

Reston, T. J.; Ranero, César R.; Belykh, I.

doi:10.1029/98jb02640

Cited by 33 publications

(44 citation statements)

References 48 publications

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“…However, the mechanics of either of the proposed processes is not understood. We point out that the geometry of crustal re£ectors imaged by seismic studies [49] is intriguingly similar to that of climbing sills, as predicted by theoretical models (Fig. 2), and observed in the ¢eld (Fig.…”

Section: Discussionmentioning

confidence: 63%

“…Reston et al [49] report observations of multiple re£ectors in the Cretaceous oceanic crust in the North-West Paci¢c that dip toward the inferred (paleo) ridge axis at low (20^30³) angles, and suggest that these re£ectors might represent lithological layering, or low-angle detachment faults in the lower and middle crust. However, the mechanics of either of the proposed processes is not understood.…”

Section: Discussionmentioning

confidence: 99%

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On origin of near-axis volcanism and faulting at fast spreading mid-ocean ridges

Fialko

2001

Earth and Planetary Science Letters

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At fast and superfast spreading mid-ocean ridges, such as the East Pacific Rise, a plate boundary is defined by a narrow (tens to hundreds of meters wide) neovolcanic zone within which the bulk of the upper oceanic crust is created. However, detailed near-bottom observations indicate that the volcanic construction may occasionally persist several kilometers off of the ridge axis. It has been proposed that off-axis volcanism manifests tapping of a wide melting region that supplies magma to the ridge axis, or spatial migration of magmatic sources in the crust and upper mantle. We demonstrate that off-axis eruptions may be a natural consequence of variations in magma supply rate even if the ridge axis is stationary in space, and the magma delivery is perfectly focussed at the ridge axis. Theoretical modeling and field observations indicate that off-axis volcanism may result from magma emplacement in sills that propagate toward the surface after their characteristic horizontal size exceeds their emplacement depth. Volcanic construction and faulting due to sill intrusions may contribute to the formation of abyssal hills, arguably the most abundant relief form on Earth. ß

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Section: Discussionmentioning

confidence: 63%

Section: Discussionmentioning

confidence: 99%

On origin of near-axis volcanism and faulting at fast spreading mid-ocean ridges

Fialko

2001

Earth and Planetary Science Letters

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“…Alternatively we may consider this zone as initial oceanic crust. In oceanic crust that formed at fast spreading ridges there are examples of upper crustal reflections at similar depth beneath a distinct top basement reflection [e.g., Ranero et al , 1997; Reston et al , 1999]. The origin of these reflections remains unclear.…”

Section: Discussionmentioning

confidence: 99%

Birth of a volcanic margin off Argentina, South Atlantic

Franke

Ladage

Schnabel

et al. 2010

Geochem Geophys Geosyst

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[1] Based on a dense grid of multichannel reflection seismic lines we study the evolution of a volcanic rifted margin segment off Argentina. The segment under study is located between 44°S and 41°S. We describe in detail the facies of the extrusive basaltic complexes across the margin. These include single and multiple Inner Seaward Dipping Reflectors (SDRs) with varying architecture along the margin, Outer Highs, and Outer SDR wedges. A detailed interpretation of a transitional zone between the Inner and Outer SDR wedges is presented. Multiple Inner SDRs are concentrated at the southern part of the margin segment, while in the north only one steeply dipping wedge is present. The dip of the Inner SDR wedges changes along the margin, and we propose subsidence by loading as main cause. The transitional zone between the Inner and Outer SDR wedges becomes narrower toward the north. By correlating with magnetic data we conclude that the emplacement of the 30-100 km wide multiple Inner SDRs occurred episodically. We propose an injection center which migrated in a seaward direction with proceeding extension as the origin for the multiple Inner SDRs. A scissor-like opening of the margin segment resulted in different amounts of stretching along-strike of the margin segment and is likely the cause for the varying distribution of the extrusive basaltic complexes. The varying extension rates within the margin segment contribute to decreasing volumes of melts generated in a northward direction within this rift segment.Components: 9834 words, 12 figures, 1 table.

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“…To further validate the nature of the intracrustal/mantle reflectivity, we applied an independent processing flow involving dip‐moveout with water or basement root‐mean‐square velocity, F‐K filtering, and poststack time migration. This analysis approach has been used to eliminate contamination from out‐of‐plane seafloor or basement reflections in previous studies of oceanic crust (Calvert, ; Canales et al, ; Kent et al, ; Ranero et al, ; Reston et al, ; supporting information Figure S3). Most of the events present on images obtained through this approach are consistent with those in our PSTM images, confirming that these events are genuine intracrustal/mantle reflections.…”

Section: Methodsmentioning

confidence: 99%

Along‐Trench Structural Variations of the Subducting Juan de Fuca Plate From Multichannel Seismic Reflection Imaging

et al. 2018

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To characterize the along‐strike structural variations of the Juan de Fuca (JdF) Plate as it enters the Cascadia subduction zone, we present prestack time migrated multichannel seismic reflection images of the JdF Plate along a 400‐km‐long trench‐parallel transect extending from 44.3°N to 47.8°N. Beneath the 1.8–3.0‐km‐thick sediment cover, our data reveal basement topographic anomalies associated with a 1.2‐km‐high seamount and in the vicinity of propagator wakes (390–540‐m relief). Weak Moho reflections are imaged beneath the propagator wakes and coincide with reduced Vp in the lower crust and/or uppermost mantle. The inferred locations of propagator wakes in the downgoing plate collocate with some of the boundaries of episodic tremor and slip events. We propose that the structural and hydration heterogeneities associated with these features could lead to anomalous plate interface properties and contribute to episodic tremor and slip segmentation. Intracrustal reflections with apparent dips (20°–30°) consistent with subduction bending normal faults change near 45.8°N, from northward dipping reflections confined to the middle crust in the north to antithetic reflections through the crust in the south, coinciding with a Vp reduction in the lower crust. These observations indicate more extensive faulting deformation and associated hydration of the JdF Plate south of 45.8°N, which likely results from variations of slab dip and resistance to subduction across 46°N. Basement offsets and abrupt depth/amplitude changes in Moho reflections are imaged beneath the four major WNW trending strike‐slip faults that cross the Cascadia deformation front, providing strong evidence of a lower plate origin for these faults.

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The structure of Cretaceous oceanic crust of the NW Pacific: Constraints on processes at fast spreading centers

Cited by 33 publications

References 48 publications

On origin of near-axis volcanism and faulting at fast spreading mid-ocean ridges

On origin of near-axis volcanism and faulting at fast spreading mid-ocean ridges

Birth of a volcanic margin off Argentina, South Atlantic

Along‐Trench Structural Variations of the Subducting Juan de Fuca Plate From Multichannel Seismic Reflection Imaging

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