Jökull - 01.01.2017, Síða 32

Holocene lavas in Bárðardalur, NE-Iceland
Figure 4. MgO vs. K2O (wt%): (a) Bárðarbunga basement rocks and other eruptive units north of Vatnajökull
and (b) the Bárðardalur region. Y vs. Zr (ppm): (c) Bárðarbunga basement rocks and other eruptive units north
of Vatnajökull and (d) the Bárðardalur region. Grey points denote published data from Bárðarbunga and the
NRZ (Jakobsson, 1979; Nicholson et al., 1991; Stracke et al., 2003; Halldórsson et al., 2008; Óladóttir, 2009;
Hartley, 2012; Manning and Thirlwall, 2014; Halldórsson, unpublished). Error bars are smaller than or identical
to the size of the symbols. WR: whole rock; GR: groundmass. – MgO á móti K2O (þunga%): (a) berggrun-
nur Bárðarbungu og aðrar goseiningar norðan Vatnajökuls og (b) hraun Bárðardals. Y á móti Zr (ppm): (c)
berggrunnur Bárðarbungu og aðrar goseiningar norðan Vatnajökuls og (d) hraun Bárðardals. Áður birt gögn
frá Norðurgosbeltinu og Bárðarbungu eru merkt með gráum punktum.
Radiogenic Isotope Characteristics
Bárðarbunga and eruptive units north of Vatnajökull
Sr-Nd-Hf isotopic ratios of samples from Bárðar-
bunga basement rocks, Dyngjuháls and Gígöldur (Ta-
ble 2 and Figure 5a, c and e) are in good agreement
with published data for Bárðarbunga and the NVZ, but
differ from most other rift and flank zones, which gen-
erally extend to more radiogenic values (e.g. Thirlwall
et al., 2004; Peate et al., 2010).
Strontium isotope ratios of basement rocks from
the Bárðarbunga central volcano and Dyngjuháls fall
JÖKULL No. 67, 2017 27