and seismic interpretation of Kangerlussuaq, West Greenland

swedishstreakMechanics

Feb 22, 2014 (3 years and 3 months ago)

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The
stratigraphic

history and climate evolution based on sediment cores
and seismic interpretation of Kangerlussuaq, West Greenland

Johan
Ploug

Technical

University

of
Denmark, Department
of Civil
Engineering,
Arctic

Technology

Centre

EGU General
Assembly

April 23
-
27 2012

The maps show the
position of the
Kangerlussuaq fjord and
the central inset shows the
fjord specifically. The dots
denote where the three
gravity cores have been
taken. Each core is
between 4 and 5 meters
long, but contain different
segments of sedimentary
mud and sand intervals.
Two cores were taken on
the large laminated feature
near the end of the deep
part of the fjord (to the
left). The last core was
taken in the laminated
sediments about half way
through the deep part, see
the seismic line for exact
positions.


Acknowledgements
:

I
would

like

to
thank

the
Commission

for
Scientific

Research in Greenland (KVUG) for
providing

financial

support
during

the
ship

cruise in 2008. IHS (former SMT) for the
use

of
KINGDOM Suite software. Morten Holtegaard for
Matlab

assistance. DTU Byg for
providing

financial

support for the
PhD

thesis
.


Contact

information:

Johan Ploug

ARTEK, DTU Byg

E
-
mail:
joplo@byg.dtu.dk

In 2008, a research group from University of Aarhus and the Technical
University of Denmark sailed the full extent of Kangerlussuaq while using a
boomer, to shoot seismic profiles of the fjord. In 1991, a multichannel
study was carried out along the same fjord. This grants a unique possibility
to investigate both the sediment thickness on bedrock and some of the
sedimentary structures in the fjord. The sediment thickness will be a means
to determine how much sediment has been provided the fjord since the
LGM and the glacial retreat.

The Kangerlussuaq Fjord
with

the
seismic

line and the
three

cores
. The
Sarfatôq

River
outlet

just
south

of the
first

core





Two cores from the sediment structure depicted in the inset. They contain little shell material, but show a
distinct lamination in the muddy layers, and a distinct
interbedding

with coarser sand intervals. The coarser
material is either slumps from the fjord sides and from the nearby Sarfartôq River.

The core from the deep laminated part of the fjord contains many shell fragments. 14C has been sampled
from the shells and have shown a short
timespan

of just 1000 years through the core. Coupling the
sedimentation rate with the amount of sediment in the fjord, we hope to establish a better interpretation
of the deglaciation in the Kangerlussuaq fjord.

The gaps in the cores represent samples taken for OSL dating. We have tried to take top and base samples
where applicable in order to get full ages, although the margin of error is high on a short time span of 1000
years.

XRF core scans have been made on the three cores. Further work encompass correlating the sediment
stratigraphy with
biostratigraphy

and
chemostratigraphy

to show the climate evolution through the
deglaciation.