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Crustal structure above the Iceland mantle plume imaged by the ICEMELT refraction profile

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dc.contributor Háskóli Íslands
dc.contributor University of Iceland
dc.contributor.author Darbyshire, Fiona A.
dc.contributor.author Bjarnason, Ingi Þorleifur
dc.contributor.author White, Robert S.
dc.contributor.author Flóvenz, Ólafur G.
dc.date.accessioned 2018-02-13T13:55:30Z
dc.date.available 2018-02-13T13:55:30Z
dc.date.issued 1998-12
dc.identifier.citation Darbyshire, F. A., Bjarnason, I. T., White, R. S., & Flóvenz, Ó. G. (1998). Crustal structure above the Iceland mantle plume imaged by the ICEMELT refraction profile. Geophysical Journal International, 135(3), 1131-1149. doi:10.1046/j.1365-246X.1998.00701.x
dc.identifier.issn 0956-540X
dc.identifier.issn 1365-246X (eISSN)
dc.identifier.uri https://hdl.handle.net/20.500.11815/568
dc.description.abstract 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 coast (surface rocks of age 8.5–3.3 Myr), crossing central Iceland (surface rocks of age 3.3–0 Myr) over the glacier Vatnajökull, below which the locus of the Iceland mantle plume is currently centred. The crustal thickness is 25 km at the north end of the profile, increasing to 38–40 km beneath southern central Iceland. The upper crust is characterized by seismic P-wave velocities from 3.2 to approximately 6.4 km s−1. At the extreme ends of the profile, the upper crust can be modelled by a two-layered structure, within which seismic velocity increases with depth, with a total thickness of 5–6 km. The central highlands of Iceland have a single unit of upper crust, with seismic velocity increasing continuously with depth to almost 10 km below the surface. Below the central volcanoes of northern Vatnajökull, the upper crust is only 3 km thick. The lower-crustal velocity structure is determined from rays that turn at a maximum depth of 24 km below central Iceland, where the seismic velocity is 7.2 km s−1. Below 24 km depth there are no first-arriving turning rays. The Moho is defined by P-and S-wave reflections observed from the shots at the extreme ends of the profile.P- to S-wave velocity ratios give a Poisson's:of 0.26 in the upper crust and 0.27 in the lower crust, indicating that, even directly above the centre of the mantle plume, the crust is well below the solidus temperature.
dc.description.sponsorship We thank Rob Staples for assistance and many helpful discussions. This work is funded by the Natural Environment Research Council (NERC) and National Science Foundation research grants; FD is supported by NERC. Instruments were loaned by the University of Cambridge, the University of Iceland, the NERC Geophysical Equipment Pool, the PASSCAL instrument pool, the Lamont-Doherty Earth Observatory, the Nordic Volcanological Institute, the University of Oregon and St Louis University. We thank Jósef Hólmjárn (shotmaster) and all who assisted in the field: Rob Staples and Mark Muller (Cambridge); Rob Dunn (Oregon); Yang Shen (Woods Hole); Arnar Hjartarson and Ólafur Rognvaldsson (Orkustofnun); Hrappur Magnusson (independent), Randy and Adriana Kuehnel (The Carnegie Institute of Washington, DTM); also Einar Kjartansson (independent) and Bob Busby (PASSCAL). Thanks to the wardens of the mountain huts at Nýidalur and Laugafell, and special thanks to Magnús Óskarsson and his family at the farm Sölvanes for looking after us and allowing us to store equipment at the farm. We thank Clare Enright for invaluable assistance with code and with data processing, and Helgi Torfason for supplying unpublished geological maps. Department of Earth Sciences, Cambridge, contribution number 5208.
dc.format.extent 1131-1149
dc.language.iso en
dc.publisher Oxford University Press (OUP)
dc.relation.ispartofseries Geophysical Journal International;135(3)
dc.rights info:eu-repo/semantics/openAccess
dc.subject Crustal structure
dc.subject Iceland
dc.subject Mantle plume
dc.subject Seismic refraction
dc.subject Jarðskorpa
dc.subject Jarðmöttull
dc.subject Jarðskjálftar
dc.subject Jarðeðlisfræði
dc.title Crustal structure above the Iceland mantle plume imaged by the ICEMELT refraction profile
dc.type info:eu-repo/semantics/article
dc.description.version Peer Reviewed
dc.identifier.journal Geophysical Journal International
dc.identifier.doi 10.1046/j.1365-246X.1998.00701.x
dc.relation.url http://academic.oup.com/gji/article-pdf/135/3/1131/1728951/135-3-1131.pdf
dc.contributor.department Raunvísindastofnun (HÍ)
dc.contributor.department Science Institute (UI)
dc.contributor.school Verkfræði- og náttúruvísindasvið (HÍ)
dc.contributor.school School of Engineering and Natural Sciences (UI)

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