Jökull - 01.01.2015, Qupperneq 26

Sigmarsson and Halldórsson
ÁGRIP
Eldstöðvakerfi eru grunneining í gosbeltum Íslands.
Megineldstöð og sprungurein, eða hvort um sig, geta
talist eldstöðvakerfi. Rekhrinunni 2014 í Bárðar-
bungu-Veiðivatnakerfinu lauk með sprungugosi í
rein sem hefur verið talin til eldstöðvakerfis Öskju.
Samsetning basaltsins sem upp kom er hins vegar
mjög svipuð þeirri sem einkennir Veiðivatnareinina.
Samsætumælingar Sr og Nd í þremur sýnum frá gos-
inu í Holuhrauni gefa sömu hlutföll 87Sr/86Sr og
143Nd/144Nd og mælst hafa í nútíma gosbergi Bárðar-
bungu-Veiðivatnakerfisins. Ólík hlutföll mælast í
hraunum Öskjukerfisins og einnig í Þjórsárhrauni og
tveim gömlum hraunum á jöðrum Veiðivatnareinar-
innar. Ólík samsætuhlutföll í gosefnum aðliggjandi
eldstöðvakerfa koma að notum við að finna hvaðan
goseiningar eru ættaðar, sem er grundvöllur fyrir mati
á gostíðni og kvikuframleiðni hvers eldstöðvarkerfis.
REFERENCES
Chekol, T. A., K. Kobayashi, T. Yokoyama, C. Sakaguchi
and E. Nakamura 2011. Timescales of magma differ-
entiation from basalt to andesite beneath Hekla Vol-
cano, Iceland: Constraints from U-series disequilib-
ria in lavas from the last quarter-millennium flows.
Geochim. Cosmochim. Acta 75, 256–283.
Einarsson, P. and H. Björnsson 1990. Volcanoes be-
neath Vatnajökull, Iceland: Evidence from radio echo-
sounding, earthquakes and jökulhlaups. Jökull 40,
147–168.
Einarsson, P. and K. Saemundsson 1987. Earthquake epi-
centers 1982–1985 and volcanic systems in Iceland
(map), in Í Hlutarins Eðli: Festschrift for Þorbjörn
Sigurgeirsson, Th. Sigfússon (ed.), Reykjavík, Menn-
ingarsjóður.
Furman, T., F. Frey and K. H. Park 1995. The scale of
source heterogeneity beneath the Eastern neovolcanic
zone, Iceland. J. Geol. Soc. 152, 997–1002.
Halldórsson, S. A., N. Óskarsson, K. Grönvold, G.
Sigurðsson, G. Sverrisdóttir and S. Steinþórsson
2008. Isotopic-heterogeneity of the Thjorsa lava-
implications for mantle sources and crustal processes
within the Eastern Rift Zone, Iceland. Chem. Geol.
255, 305–316.
Hartley, M. E. and Th. Thordarson 2013. The 1874–
1876 volcano-tectonic episode at Askja, North
Iceland: Lateral flow revisited. G-cubed 14,
doi:10.1002/ggge.20151.
Hémond, C., N. T. Arndt, U. Lichtenstein, A. Hofmann, N.
Oskarsson and S. Steinthórsson 1993. The heteroge-
neous Iceland plume: Nd-Sr-O isotopes and trace ele-
ment constraints. J. Geophys. Res. 98, 15833–15850.
Hjartarson, Á. 2004. Hraunin í Bárðardal. Náttúrufræðing-
urinn 72, 155–163.
Jakobsson, S. P. 1979. Petrology of the recent lavas of
the Eastern Volcanic Zone, Iceland. Acta Naturalia Is-
landica 26, 1–103.
Jónsson, G., L. Kristjánsson and M. Sverrisson 1991.
Magnetic surveys of Iceland. Tectonophys. 189, 229–
247.
Jóhannesson, H., and K. Sæmundsson 1998. Jarðfræðikort
af Íslandi. 1:500 000. Höggun. Náttúrufræðistofnun
Íslands, Reykjavík (1. útgáfa).
Kempton, P.D. et al. 2000. The Iceland plume in space and
time: a Sr-Nd-Pb-Hf study of the North Atlantic rifted
margin. Earth Planet. Sci. Lett. 177, 255–271.
Kokfelt, T. F., K. Hoernle, F. Hauff, J. Fiebig, R. Werner
and D. Garbe-Schönberg 2006. Combined trace ele-
ment and Pb-Nd-Sr-O isotope evidence for recycled
oceanic crust (upper and lower) in the Iceland mantle
plume. J. Petrol. 214, 167–186.
Kokfelt, T. F., K. Hoernle, C. Lundstrom, F. Hauff and
C. van den Bogaard 2009. Time-scales for magmatic
differentiation at the Snaefellsjökull central volcano,
western Iceland: Constraints from U-Th-Pa-Ra dise-
quilibria in post-glacial lavas. Geochim. Cosmochim.
Acta 73, 1120–1144.
Konter, J. G. and L. P. Storm 2014. High precision
87Sr/86Sr measurements by MC-ICP-MS, simultane-
ously solving for Kr interferences and mass-based
fractionation. Chem. Geol. 385, 26–34.
Koornneef, J. M., A. Stracke, B. Bourdon, M. A. Meier,
K. P. Jochum, B. Stoll and K. Grönvold 2012. Melting
of a two-component source beneath Iceland. J. Petrol.
53, 127–157.
Kuritani, T., T. Yokoyama, H. Kitagawa, K. Kobayashi and
E. Nakamura 2011. Geochemical evolution of histor-
ical lavas from Askja volcano, Iceland: Implications
for mechanisms and timescales of magmatic differen-
tiation. Geochim. Cosmochim. Acta 75, 570–587.
Manning, C. J. and M. F. Thirlwall 2014. Isotopic evidence
for interaction between Öræfajökull mantle and the
Eastern Rift Zone, Iceland. Contrib. Mineral. Petrol.
167: 959, doi:10.1007/s00410-013-0959-1.
26 JÖKULL No. 65, 2015