
Iceland
Keck 2007 group:
left to right: Mike Bernstein (Amherst College), Kamilla Fellah (College of
Wooster), Dan Hadley (Augustana College)
Paul Olin (Washington State Univ.), Brennan Jordan (Univ. of South Dakota),
Caitlyn Perlman (Colgate University)
Beth Drewes (DePauw University), Lynne Stewart (Oberlin College). Not
shown: Bob Wiebe (Franklin & Marshall College)
Director: Brennan Jordan
(The University of South Dakota)
Bob Wiebe
(Franklin and Marshall College)
TA: Paul Olin (Washington State University)
Overview:
Six students representing the Keck
Consortium joined the project faculty on a month-long research
expedition to the Westfjords of northwestern Iceland. The project followed
up on the 2003 and 2004
Iceland Keck projects, by focusing on the Arnes central volcano which falls in
between the two previously studied sites. The Mid-Atlantic Ridge is exposed above sea
level
at Iceland (Fig. 1) due to the
interaction
of the ridge with a hotspot (generally interpreted as a mantle
plume).
Plate motion causes the ridge to migrate westward off of the
hotspot.
The ridge periodically ‘jumps’ to recenter on the hotspot, abandoning
the
old ridge. The last
ridge-segment
to be abandoned goes through the Skagi area and Snæfellsnes
Peninsula;
it was active from 15 to 7 Ma (Fig.
2). The Arnes central volcano formed on the now abandoned rift about
11 million years ago, in between the times of activity at the previous Keck
project sites (Westfjords ~14 Ma, and Skagi 8.6-7.0 Ma. All three
projects focused on the areas around Tertiary central volcanoes
where diverse arrays of compositions (basalt to rhyolite) could be
studied. Our studies included mapping and sampling in the field
and petrography and
geochemistry (XRF and ICP-MS) back in the lab. During the 2007-2008
academic year the students and faculty of the project will collaborate to
interpret the geochemistry and petrography of these rocks to document the
processes of magma genesis in the Arnes central volcano and to compare and
contrast these results with the 2003 and 2004 study areas. We will then
consider the implications for variation in petrologic processes on the rift
through time and the implications for models of rifting and mantle plume
activity in Iceland.