Jökull - 01.01.2012, Blaðsíða 3

Glaciology and volcanology on the centenary of Sigurður
Þórarinsson’s birth: a special issue
The year 2012 marks the centenary of the birth of the
late Sigurður Þórarinsson, the first professor of geol-
ogy at the University of Iceland. His legacy is widely
recognized in the international geoscientific commu-
nity and the highest award of the International Associ-
ation of Volcanology and Chemistry of the Earth’s In-
terior (IAVCEI), the Thorarinsson Medal, is awarded
to scientists for outstanding contributions to volcanol-
ogy. Sigurður’s influence on Icelandic geoscientists
was immense both through his university teaching
and scientific collaborations. Although his research
spanned a broad range of geosciences, including e.g.
physical geography, geomorphology, periglacial fea-
tures, and studies of interglacial sediments and tec-
tonic earthquakes, his main fields of research were
glaciology and volcanology in a broad context. Sig-
urður was president of the Iceland Glaciological So-
ciety from 1969 till his death, leader of most of its
annual expeditions to Vatnajökull from 1953, and co-
editor and frequent contributor to its scientific journal
Jökull. This special issue of Jökull is dedicated to Sig-
urður’s contribution to geosciences and long-lasting
influence on research in glaciology and volcanology
in Iceland.
This special issue contains an overview of Sig-
urður Þórarinsson’s life and scientific career by Sig-
urður Steinþórsson, ten peer-reviewed papers on dif-
ferent aspects of glaciology, glacial geomorphology
and volcanology, Sigurður’s principal research fields
and three society documentaries by two of Sigurður’s
travel companions.
Sigurður developed tephrochronology, an off-
spring of volcanology, as a tool for studying erup-
tion history and as a dating method which he ap-
plied widely on archaeological problems and explo-
ration of environmental processes, such as soil erosion
and glacier fluctuations. This is reflected by papers
dealing with tephrochronology and, thus, expanding
its foundation laid by Sigurður in 1944. Óladóttir et
al. show how terrestrial tephra layers record eruption
mechanism and frequency, depth of magma storage,
and the behaviour of volcanic systems, all of which
are relevant for assessments and predictions of future
volcanic activity. Dugmore and Newton discuss how
analyses of poorly-identified, un-provenanced and re-
mobilised tephras can advance understanding of geo-
morphological processes and human-environment in-
teraction and identify shifts in landscape stability and
land use. Guðmundsdóttir et al. review the Holocene
marine tephrochronology on the shelf around Iceland,
correlate it to the terrestrial record, and discuss the
potentials in using marine tephrochronology for dat-
ing purposes, estimations of ocean reservoir age, and
reconstructions of the past activity of Icelandic volca-
noes. Finally, Wastegård and Boygle provide a brief
overview on the distal tephrochronology of Scandi-
navia where 16 tephra layers have been identified in
lakes and bogs in Sweden, at least 13 of which origi-
nate from Icelandic volcanoes.
Following are six papers dealing with glaciol-
ogy and glacial geomorphology that relate to Sig-
urður Þórarinsson’s interest in the history, behaviour,
and surges of Icelandic glaciers. Pálsson et al. dis-
cuss mass and volume changes of the Langjökull ice
cap from 1890 to 2009 and its sensitivity to climate
change. Guðmundsson et al. describe the volume
loss of the Kotárjökull glacier since the Little Ice
Age and contrasting responses of the lower and up-
per parts of the glacier to the 20th century climate
warming. Recent and Late Holocene changes of the
Sólheimajökull glacier are discussed by Schomacker
et al., who suggest a major advance around 1.9 ka BP
JÖKULL No. 62, 2012 1