First results from the Reykjanes Ridge Iceland Seismic Project 1977

Angenheister, G.; Gebrande, H.; Miller, Heinz; Weigel, W.; Goldflam, P.; Jacoby, W. R.; Pálmason, Guðmundur; Björnsson, Sveinbjörn; Einarsson, Páll; Zverev, S. M.; Loncarevic, B. D.; Solomon, Sean C.

doi:10.1038/279056a0

Cited by 15 publications

(12 citation statements)

References 11 publications

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“…They provide evidence that crust generated within the last several million years varies from 8 to 10 km thick. A, Angenheister et al [1980]; B, Smallwood and White [1998]; C, Bunch and Kennett [1980]. in the region of wet melting (i.e., deeper than the depth to the dry solidus), where the competing effects on viscosity from grain boundary sliding and dehydration are likely to be of similar magnitude.…”

Section: Buoyancy and Viscositymentioning

confidence: 90%

From rift to drift: Mantle melting during continental breakup

Nielsen

Hopper

2004

Geochem Geophys Geosyst

133

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[1] Volcanic rifted margins show a temporal evolution in igneous crustal thickness and thus provide additional insights into mantle dynamics compared to the steady state situation at mid-ocean ridges. Although details between different provinces vary, volcanic rifted margins generally show a short-lived pulse of extreme magmatism that quickly abates to a steady state mid-ocean ridge. The generation of thick igneous crust at volcanic rifted margins requires either melting of hot mantle material to higher degrees than observed at mid-ocean ridges or melting of larger amounts of mantle material than would be the case for plate-driven upwelling. To assess under what conditions buoyantly driven upwelling or small-scale convection at rifting plate boundaries is important, a fluid dynamical model with non-Newtonian viscosity that includes the feedback from melting on the physical properties of the mantle is developed. To generate a pulse of high magmatic production requires a viscosity and density structure that also leads to excessive fluctuations in magmatic productivity or a sustained high productivity that continues long after breakup. A viscosity increase due to dehydration caused by melting effectively suppresses buoyant upwelling above the depth to the dry solidus, thereby restricting shallow flow to plate-driven upwelling. While this stabilizes the time dependence and forces the productivity to values consistent with mid-ocean ridge accretion, it does so at the expense of eliminating the breakup instability. Models that assume an abrupt change in prerift lithospheric thickness suffer from the same deficits. However, including a sublithospheric hot layer leads to a model that can predict the temporal evolution of igneous crustal thickness observed in refraction seismic data from the southeast Greenland volcanic rifted margin.Components: 12,940 words, 15 figures, 1 table.

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Section: Buoyancy and Viscositymentioning

confidence: 90%

From rift to drift: Mantle melting during continental breakup

Nielsen

Hopper

2004

Geochem Geophys Geosyst

133

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“…A thin-crust model was developed and widely accepted during the 1980's and early 1990's (Angenheister et al, 1979;Beblo and Björnsson, 1980;Flóvenz and Gunnarsson, 1991;Flóvenz and Saemundsson, 1993;Gebrande et al, 1980;Mayer et al, 1985;Pálmason, 1986;Saemundsson, 1978). It relied on measurements of electrical resistivity in the crust and mantle, correlated with various seismic data, heat-flow measurements, petrological information, crustal elasticity and theoretical modeling.…”

Section: Crustal Structurementioning

confidence: 99%

“…As discussed by Foulger et al (2005b), a hot and thin crust would imply that the volume of any melting anomaly is small or even insignificant whereas a thick and cold crustal model would require a large melting anomaly. For this reason, numerous studies have been conducted to determine Icelandic crustal structure using different techniques over the years (Allen et al, 2002;Angenheister et al, 1979;Bjarnason et al, 1993;Darbyshire et al, 1998Darbyshire et al, , 2000aDarbyshire et al, , 2000bFoulger, 1999, 2001;Flóvenz and Gunnarsson, 1991;Foulger, 2002;Foulger et al, 2003;Kaban et al, 2002;Kumar et al, 2007;Menke et al, 1996Menke et al, , 1998Staples et al, 1997). As a result, it has been established that the crust under Iceland has oceanic affinity.…”

Section: Introductionmentioning

confidence: 96%

Iceland structure and volcanism: An alternative vision based on the model of volcanic systems

Savry¹,

Cañón‐Tapia²

2014

Tectonophysics

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“…For the present problem, we define the spread function for a single averaging vector, following Refraction profiles collected near the Hengill area [Palmason, 1971] provide good constraints on the laterally averaged P-wave velocity structure (Figure 4). Steep velocity gradients (1 s~ ) are present at shallow depths (0-3 km), low velocity gradients (0.1-0.2 s~ ) occur from 3 to 10 km depth, and a halfspace velocity of 7.0 km/s at 10 km depth is assumed, based on the work of Angenheister et al [1980]. This velocity structure was used by Foulger [1984] in the calculation of the microearthquake hypocentral parameters.…”

Section: Discussionmentioning

confidence: 99%

The tectonics and three-dimensional structure of spreading centers : microearthquake studies and tomographic inversions

Toomey¹

1987

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Two-thirds of the Earth's surface has been formed along a global system of spreading centers that are presently manifested in several different structural forms, including the classic rift valley of the Mid-Atlantic Ridge, the more morphologically subdued East Pacific Rise, and the pronounced en echelon structure of the Reykjanes Peninsula within southwestern Iceland. In this thesis, each of these different spreading centers is investigated with microearthquake studies or tomographic inversion of travel times. Results of these studies are used to constrain the spatial variability of physical properties and processes beneath the axis of spreading and, together with other observations, the temporal characteristics of crustal accretion and rifting.

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First results from the Reykjanes Ridge Iceland Seismic Project 1977

Cited by 15 publications

References 11 publications

From rift to drift: Mantle melting during continental breakup

From rift to drift: Mantle melting during continental breakup

Iceland structure and volcanism: An alternative vision based on the model of volcanic systems

The tectonics and three-dimensional structure of spreading centers : microearthquake studies and tomographic inversions

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