Evolution of the East Pacific Rise at 16�?19� S since 5 Ma: Bisection of overlapping spreading centers by new, rapidly propagating ridge segments

Cormier, Marie-Hélène; Scheirer, Daniel S.; Macdonald, Ken C.

doi:10.1007/bf00286203

Cited by 47 publications

(58 citation statements)

References 102 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Bird & Naar 1994;Cormier et al 1996); the role of lateral magma transport in the crust and mantle (e.g. Macdonald et al 1984;Fox et al 1995;Batiza 1996); the contribution of small upper mantle melt anomalies to segmentation (e.g.…”

Section: Questions For Future Workmentioning

confidence: 99%

“…Gomez & Briais 2000); how discontinuities evolve and grow, in particular the relationship between second-and third-order offsets at fast and intermediate ridges (e.g. Carbotte & Macdonald 1992;Cormier et al 1996;Canales et al 2002); and what drives the migration of these discontinuities (e.g. Macdonald et al 1984Schouten et al 1987;Tucholke & Schouten 1988;Lonsdale 1989Lonsdale , 1994Cormier 1997).…”

Section: Questions For Future Workmentioning

confidence: 99%

See 1 more Smart Citation

Tectonic and magmatic segmentation of the Global Ocean Ridge System: a synthesis of observations

Carbotte

Smith

Cannat

et al. 2015

View full text Add to dashboard Cite

Mid-ocean ridges display tectonic segmentation defined by discontinuities of the axial zone, and geophysical and geochemical observations suggest segmentation of the underlying magmatic plumbing system. Here, observations of tectonic and magmatic segmentation at ridges spreading from fast to ultraslow rates are reviewed in light of influential concepts of ridge segmentation, including the notion of hierarchical segmentation, spreading cells and centralized v. multiple supply of mantle melts. The observations support the concept of quasi-regularly spaced principal magmatic segments, which are 30-50 km long on average at fast-to slow-spreading ridges and fed by melt accumulations in the shallow asthenosphere. Changes in ridge properties approaching or crossing transform faults are often comparable with those observed at smaller offsets, and even very small discontinuities can be major boundaries in ridge properties. Thus, hierarchical segmentation models that suggest large-scale transform fault-bounded segmentation arises from deeper level processes in the asthenosphere than the finer-scale segmentation are not generally supported. The boundaries between some but not all principal magmatic segments defined by ridge axis geophysical properties coincide with geochemical boundaries reflecting changes in source composition or melting processes. Where geochemical boundaries occur, they can coincide with discontinuities of a wide range of scales.Discovery and interpretations of mid-ocean ridge (MOR) segmentation: historical review

show abstract

Section: Questions For Future Workmentioning

confidence: 99%

Section: Questions For Future Workmentioning

confidence: 99%

Tectonic and magmatic segmentation of the Global Ocean Ridge System: a synthesis of observations

Carbotte

Smith

Cannat

et al. 2015

View full text Add to dashboard Cite

show abstract

“…• S (Lonsdale, 1989;Cormier et al, 1996). However, some sea-surface magnetic anomaly profiles near 17.5…”

Section: Paleomagnetic Intensity and Fine-scale Tectonicsmentioning

confidence: 98%

“…This is the same balance in the eastward and westward spreading rates as our result shows, suggesting that the degree of the asymmetry becomes larger sometime before the Brunhes period and the maximum asymmetric ratio is afterward kept up to the present. Cormier et al (1996) suggests that spreading asymmetry in this area can be entirely explained by the southward migration of overlapping spreading centers (OSCs) that is an effective way to transfer the lithosphere from the Pacific to the Nazca Plates. In other words, an absence of OSCs would produce a symmetric spreading.…”

Section: Paleomagnetic Intensity and Fine-scale Tectonicsmentioning

confidence: 99%

Geomagnetic paleointensity over 1.2 Ma from deep-tow vector magnetic data across the East Pacific Rise

2005

View full text Add to dashboard Cite

Deep-tow vector magnetic data have been acquired across the fast-spreading southern East Pacific Rise 18• S and inverted to magnetization intensity variations. Vector magnetic data are used to determine continuous magnetic intensity within intervals of constant polarity over the Matuyama and Brunhes periods up to the Cobb Mountain event at 1.19 Ma. A comparison of our deep-tow vector data and a sediment core-derived geomagnetic paleointensity timescale suggests that the short-wavelength magnetic anomaly signal is indeed of geomagnetic origin and can be used to date the seafloor with a high resolution. The crustal age determined from our date reveals a highly asymmetric spreading rate for the recent period (since 0.3 Ma).

show abstract

“…Since 1 Ma, the Pacific plate has been spreading slightly faster than the Nazca plate north of 17ø15'S, at a half-rate of 75 mm/yr versus 65 mm/yr. The asymmetry reverses just south of 17ø15'S, so that the Nazca Plate is spreading eastward at a half-rate of 80 mm/yr, roughly 20 mm/yr faster than the Pacific plate half-rate [Cormier et al, 1996; D. Wilson, personal communication, 1997]. Bathymetric mapping reveals that the seafloor on the Pacific plate subsides at a slower rate than predicted by the global average of lithospheric cooling with crustal age, implying hotter mantle and thinner lithosphere on the west flank [Cochran, 1986;Scheirer et al, 1998].…”

Section: Overview Of the Epr From 15 ø To 20øsmentioning

confidence: 99%

Distribution of isolated volcanoes on the flanks of the East Pacific Rise, 15.3°S–20°S

White¹,

Macdonald²,

Scheirer³

et al. 1998

J. Geophys. Res.

Self Cite

View full text Add to dashboard Cite

Abstract. Volcanic constructions, not associated with seamount (or volcano) chains, are abundant on the flanks of the East Pacific Rise (EPR) but are rare along the axial high. The distribution of isolated volcanoes, based on multibeam bathymetric maps, is approximately symmetric about the EPR axis. This symmetry contrasts with the asymmetries in the distribution of volcano chains (more abundant on the west flank), the seafloor subsidence rates (slower on the west flank), and the distribution of plate-motion-parallel gravity lineaments (more prominent on the west flank). Most of the isolated volcanoes complete their growth within -14 km of the axis on crust younger than 0.2 Ma, while seamount chain volcanoes continue to be active on older crust. Volcanic edifices within 6 km of the ridge axis are primarily found adjacent to axial discontinuities, suggesting a more sporadic magma supply and stronger lithosphere able to support volcanic constructions near axial discontinuities. The volume of isolated near-axis volcanoes correlates with ridge axis cross-sectional area, suggesting a link between the magma budget of the ridge and the eruption of near-axis volcanoes. Within the study area, off-axis volcanic edifices cover at least 6% of the seafloor and contribute more than 0.2% to the volume of the crust. The inferred width of the zone where isolated volcanoes initially form increases with spreading rate for the Mid-Atlantic Ridge (<4 km), northern EPR (<20 km), and southern EPR (<28 km), so that isolated volcanoes form primarily on lithosphere younger than 0.2 Ma (< 4-6 km brittle thickness), independent of spreading rate. This suggests some form of lithospheric control on the eruption of isolated off-axis volcanoes due to brittle thickness, increased normal stresses across cracks impeding dike injection, or thermal stresses within the newly forming lithosphere.

show abstract

Evolution of the East Pacific Rise at 16�?19� S since 5 Ma: Bisection of overlapping spreading centers by new, rapidly propagating ridge segments

Cited by 47 publications

References 102 publications

Tectonic and magmatic segmentation of the Global Ocean Ridge System: a synthesis of observations

Tectonic and magmatic segmentation of the Global Ocean Ridge System: a synthesis of observations

Geomagnetic paleointensity over 1.2 Ma from deep-tow vector magnetic data across the East Pacific Rise

Distribution of isolated volcanoes on the flanks of the East Pacific Rise, 15.3°S–20°S

Contact Info

Product

Resources

About