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Titolo:
Crustal structure of the northern Reykjanes Ridge and Reykjanes Peninsula,southwest Iceland
Autore:
Weir, NRW; White, RS; Brandsdottir, B; Einarsson, P; Shimamura, H; Shiobara, H;
Indirizzi:
Univ Cambridge, Bullard Labs, Cambridge CB3 0EZ, England Univ Cambridge Cambridge England CB3 0EZ abs, Cambridge CB3 0EZ, England Univ Iceland, Inst Sci, IS-107 Reykjavik, Iceland Univ Iceland ReykjavikIceland IS-107 nst Sci, IS-107 Reykjavik, Iceland Hokkaido Univ, Inst Seismol & Volcanol, Sapporo, Hokkaido 0600810, Japan Hokkaido Univ Sapporo Hokkaido Japan 0600810 oro, Hokkaido 0600810, Japan Univ Tokyo, Earthquake Res Ctr, Bunkyo Ku, Tokyo 1130032, Japan Univ Tokyo Tokyo Japan 1130032 Res Ctr, Bunkyo Ku, Tokyo 1130032, Japan
Titolo Testata:
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
fascicolo: B4, volume: 106, anno: 2001,
pagine: 6347 - 6368
SICI:
0148-0227(20010410)106:B4<6347:CSOTNR>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
MID-ATLANTIC RIDGE; SLOW-SPREADING RIDGE; VELOCITY STRUCTURE; PLATE BOUNDARY; OCEANIC-CRUST; MANTLE PLUME; BATHYMETRY; ZONE; TEMPERATURE; EARTHQUAKES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
74
Recensione:
Indirizzi per estratti:
Indirizzo: Weir, NRW Univ Cambridge, Bullard Labs, Madingley Rd, Cambridge CB3 0EZ, England Univ Cambridge Madingley Rd Cambridge England CB3 0EZ , England
Citazione:
N.R.W. Weir et al., "Crustal structure of the northern Reykjanes Ridge and Reykjanes Peninsula,southwest Iceland", J GEO R-SOL, 106(B4), 2001, pp. 6347-6368

Abstract

Results from the Reykjanes-Iceland Seismic Experiment (RISE) show that thethickness of zero-age crust decreases from 21 km in southwest Iceland to 11 km at 62 degrees 40 'N on the Reykjanes Ridge. This implies a decrease inmantle potential temperature of similar to 130 degreesC, with increasing distance from the center of the Iceland mantle plume, along this 250 km transect of the plate boundary. The crust thins off-axis at 63 degreesN, from 12.7 km thick at 0 Ma to 9.8 km at 5 Ma, most likely due to a similar to 40 degreesC change in asthenospheric mantle temperature between these times. This provides evidence for the passage of a pulse of hotter asthenospheric mantle material beneath the present spreading center. A reflective body, thetop of which lies at 9-11 km depth, is identified in the lower crust just west of the tip of the Reykjanes Peninsula. Synthetic seismogram modeling of the wide-angle reflections from this body suggests that it corresponds toa zone of high-velocity (greater than or equal to7.5 km s(-1)), high-magnesium rocks in the lower crust. The P to S wave velocity ratio beneath the peninsula is 1.78, implying that crustal temperatures are below the solidus. Gravity modeling shows the RISE models to be consistent with the observed gravity field. Mantle densities are lower beneath the ridge axis than beneath older crust, consistent with lithospheric cooling with age.

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Documento generato il 05/04/20 alle ore 17:14:13