Opin vísindi

Browsing by Subject "Jarðmöttull"

Browsing by Subject "Jarðmöttull"

Sort by: Order: Results:

  • Bjarnason, Ingi Þorleifur (Hið íslenska náttúrufræðifélag, 1997)
    Heitur reitur er landsvæði sem einkennist af mikilli eldvirkni og jarðhita og stendur hátt yfir umhverfið. Ísland er einn af stærstu heitu reitum jarðar og gnæfir 2-4 km yfir venjulega hæð Norður-Atlantshafshryggjarins sem gengur í gegnum landið. Markmið ...
  • Wolfe, Cecily J.; Bjarnason, Ingi Þorleifur; VanDecar, John C.; Solomon, Sean C. (Wiley-Blackwell, 2002)
    Earlier inversions of body wave delay-time data recorded during the ICEMELT portable broadband experiment imaged a cylindrical plume-like low-velocity anomaly extending to at least 400 km depth beneath Iceland, but the depth extent of the anomaly ...
  • Darbyshire, Fiona A.; Bjarnason, Ingi Þorleifur; White, Robert S.; Flóvenz, Ólafur G. (Oxford University Press (OUP), 1998-12)
    The crustal structure of central Iceland is modelled using data from a 310 km long refraction profile shot during summer 1995. The profile traversed Iceland from the Skagi Peninsula on the north coast (surface rocks of age 8.5–0.8 Myr) to the southeast ...
  • Wilcock, William S. D.; Webb, Spahr C.; Bjarnason, Ingi Þorleifur (The Seismological Society of America, 1999)
    The mantle electromagnetic and tomography (MELT) experiment on the east Pacific rise near 17°S was the first large teleseismic experiment on a midocean ridge. During the six-month deployment, no compressional arrivals were well recorded above 0.5 ...
  • Nikkola, Paavo (Faculty of Science, University of Helsinki; Faculty of Earth Sciences, University of Iceland, 2020-03-20)
    This thesis provides insights into the petrogenesis of Iceland basalts via three subprojects. The first uses olivine macrocrysts as a proxy for mantle melting conditions below Iceland, the second utilizes petrological thermobarometry to resolve the ...
  • Shen, Yang; Solomon, Sean C.; Bjarnason, Ingi Þorleifur; Purdy, G. M. (American Geophysical Union (AGU), 1996-12-01)
    P‐to‐S conversions from the two primary discontinuities near 410 and 660 km depth (P410s and P660s phases) are evident in particle motions and receiver functions of teleseismic body waves recorded by broadband seismic stations in Iceland. The average ...
  • Bjarnason, Ingi Þorleifur (Iceland Glaciological Society and Geoscience Society of IcelandJöklarannsóknafélags Íslands og Jarðfræðafélags Íslands, 2008)
    Is Iceland a hotspot, with ridge-centered plume? In Iceland vigorous volcanism has built up a plateau 3.0 km higher than at a normal mid-ocean ridge with 3 to 4 times thicker crust than average oceanic crust. This volcanism can be associated with ...
  • Bjarnason, Ingi Þorleifur; Schmeling, Harro (Oxford University Press (OUP), 2009-07)
    1-D models were calculated for the velocity of shear waves, polarized vertically (SV) and horizontally (SH) from dispersed Rayleigh and Love surface waves. These had been recorded in Iceland by the ICEMELT broad-band seismic network, with about half ...
  • Reply 
    Bjarnason, Ingi Þorleifur; Menke, William; Flóvenz, Ólafur G. (American Geophysical Union, 1994-09-10)
    The central question discussed by Gudmundsson [this issue] can be succinctly stated: "Is the temperature of the shallowest upper mantle of Iceland at the peridotite solidus" (nominally, 1200°C). The traditional view, as developed by numerous authors ...
  • Shen, Yang; Solomon, Sean C.; Bjarnason, Ingi Þorleifur; Wolfe, Cecily J. (Springer Nature, 1998-09)
    Iceland, one of the most thoroughly investigated hotspots1,2,3, is generally accepted to be the manifestation of an upwelling mantle plume4. Yet whether the plume originates from the lower mantle or from a convective instability at a thermal boundary ...
  • Shen, Yang; Solomon, Sean C.; Bjarnason, Ingi Þorleifur; Nolet, Guust; Morgan, W.Jason; Allen, Richard M.; Vogfjörð, Kristín; Jakobsdóttir, Steinunn; Stefánsson, Ragnar; Julian, B.R.; Foulger, G.R. (Elsevier BV, 2002-04)
    Shear waves converted from compressional waves at mantle discontinuities near 410- and 660-km depth recorded by two broadband seismic experiments in Iceland reveal that the center of an area of anomalously thin mantle transition zone lies at least 100 ...
  • Bjarnason, Ingi Þorleifur; Silver, Paul G.; Rümpker, Georg; Solomon, Sean C. (Wiley-Blackwell, 2002-12)
    We report on observations of upper mantle anisotropy from the splitting of teleseismic shear waves (SKS, SKKS, and PKS) recorded by the ICEMELT broadband seismometer network in Iceland. In a ridge-centered hot spot locale, mantle anisotropy may be ...
  • Nikkola, Paavo; Guðfinnsson, Guðmundur; Bali, Eniko; Rämö, O. Tapani; Fusswinkel, Tobias; Thordarson, Thorvaldur (Springer Science and Business Media LLC, 2019-05)
    We present new high-precision major and trace element data on olivine macrocrysts from various volcano-tectonic settings in Iceland and use these data as a proxy for mantle mode and melting conditions. Within individual sampling sites examined (seven ...
  • Kreutzmann, A.; Schmeling, Harro; Junge, A.; Ruedas, T.; Marquart, G.; Bjarnason, Ingi Þorleifur (Oxford University Press (OUP), 2004-12)
    The dynamic and melting processes of a ridge-centred plume have been investigated in a companion paper by Ruedas et al. (hereafter referred to as Paper I) in a set of 3-D numerical fluid dynamic models with varying plume excess temperatures and melt ...
  • Mundl-Petermeier, A.; Walker, R.J.; Jackson, M.G.; Blichert-Toft, J.; Kurz, M.D.; Halldórsson, Sæmundur Ari (Elsevier BV, 2019-10-20)
    Studies of short-lived radiogenic isotope systems and noble gas isotopic compositions of plume-derived rocks suggest the existence of primordial domains in Earth's present-day mantle. Tungsten-182 anomalies together with high 3He/4He in Phanerozoic ...
  • Bjarnason, Ingi Þorleifur; Menke, William; Flóvenz, Ólafur G.; Caress, David (American Geophysical Union (AGU), 1993-04-10)
    The 170 km South Iceland Seismic Tomography (SIST) profile extends from the west and across the Mid‐Atlantic Ridge spreading center in the Western Volcanic Zone and continues obliquely through the transform zone (the South Iceland Seismic Zone) to the ...
  • Thordarson, Thorvaldur; Garcia, Michael O. (Frontiers Media SA, 2018-09-04)
    The origin of rejuvenated volcanism on mantle plume related oceanic islands remains controversial. One commonly cited model is decompressional melting related to plate flexure from the rapid loading of the lithosphere by the formation of a shield ...
  • Neave, David A.; Hartley, Margaret E.; Maclennan, John; Edmonds, Marie; Thordarson, Thorvaldur (Elsevier BV, 2017-05)
    Melt inclusions formed during the early stages of magmatic evolution trap primitive melt compositions and enable the volatile contents of primary melts and the mantle to be estimated. However, the syn-and post-entrapment behaviour of volatiles in ...