Jökull - 01.01.2017, Page 26

Holocene lavas in Bárðardalur, NE-Iceland
Figure 3. Bárðardalur val-
ley and the region north
of Vatnajökull: (a) Bárð-
ardalshraun lava following
the Skjálfandafljót river to-
wards the north. (b) Patch
of the Kinnarhraun lava
northwest of lake Svartár-
vatn. (c) The Bárðardals-
hraun lava with the Trölla-
dyngja shield volcano in the
background. – Ljósmyndir
af hraunum í Bárðardal og
norðan Vatnajökuls.
plagioclase macrocrysts, is presented in a compan-
ion paper. The rock samples include newly collected
samples (B15–1 to B15–16) and a single archive sam-
ple (NAL664) from the sample collection of the In-
stitute of Earth Sciences, University of Iceland. Our
sample selection includes different parts of the large
Kinnarhraun and Bárðardalshraun lava flows (Fig-
ure 3), the prehistoric Útbruni and Kvíahraun lavas,
as well as the historical Frambruni lava. The sam-
ples were taken from interiors of larger blocks to
minimize surface weathering effects. The samples
are generally relatively fresh and unaltered. How-
ever, for some of the lava flows, especially Kinnar-
hraun and Bárðardalshraun lavas, fresh samples were
rare and most samples have somewhat prominent al-
teration features, such as visible signs of oxidation
(e.g., sample B15–10). Archive samples from base-
ment rocks and nunataks of the Bárðarbunga cen-
tral volcano, and the region north of Vatnajökull (i.e.,
Dyngjuháls, Urðarháls, Gígöldur, and Hrímalda) were
also included in this study. Additional sample details
can be found in Svavarsdóttir (2017).
ANALYTICAL TECHNIQUES
Inductively Coupled Plasma Optical Emission-
Spectroscopy (ICP-OES)
Major, minor and selected trace element analyses
were acquired for all samples of this study (Table 1).
The analyses were carried out with an ICP-OES in-
strument (SPECTRO-CIROS) at the Institute of Earth
JÖKULL No. 67, 2017 21