Geochemical signatures of pingo ice and its origin in Grøndalen, west Spitsbergen
Item
Title (Dublin Core)
Geochemical signatures of pingo ice and its origin in Grøndalen, west Spitsbergen
Description (Dublin Core)
<p>Pingos are common features in permafrost regions that
form by subsurface massive-ice aggradation and create hill-like landforms.
Pingos on Spitsbergen have been previously studied to explore their
structure, formation timing and connection to springs as well as their role in
postglacial landform evolution. However, detailed hydrochemical and
stable-isotope studies of massive-ice samples recovered by drilling have yet
to be used to study the origin and freezing conditions in pingos. Our core
record of 20.7 m thick massive pingo ice from Grøndalen is differentiated
into four units: two characterised by decreasing <span class="inline-formula"><i>δ</i><sup>18</sup>O</span> and
<span class="inline-formula"><i>δ</i></span>D and increasing <span class="inline-formula"><i>d</i></span> (units I and III) and two others showing the
opposite trend (units II and IV). These delineate changes between episodes
of closed-system freezing with only slight recharge inversions of the water
reservoir and more complicated episodes of groundwater freezing under
semi-closed conditions when the reservoir was recharged. The water source
for pingo formation shows similarity to spring water data from the valley
with prevalent <span class="inline-formula">Na<sup>+</sup></span> and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">HCO</mi><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="33pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="eb873fe7aee1cdf217b166d877fa3e0f"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-13-3155-2019-ie00001.svg" width="33pt" height="16pt" src="tc-13-3155-2019-ie00001.png"/></svg:svg></span></span> ions. The sub-permafrost
groundwater originates from subglacial meltwater that most probably followed
the fault structures of Grøndalen and Bøhmdalen. The presence of
permafrost below the pingo ice body suggests that the talik is frozen, and
the water supply and pingo growth are terminated. The maximum thaw depth of
the active layer reaching the top of the massive ice leads to its successive
melt with crater development and makes the pingo extremely sensitive to
further warming.</p>
form by subsurface massive-ice aggradation and create hill-like landforms.
Pingos on Spitsbergen have been previously studied to explore their
structure, formation timing and connection to springs as well as their role in
postglacial landform evolution. However, detailed hydrochemical and
stable-isotope studies of massive-ice samples recovered by drilling have yet
to be used to study the origin and freezing conditions in pingos. Our core
record of 20.7 m thick massive pingo ice from Grøndalen is differentiated
into four units: two characterised by decreasing <span class="inline-formula"><i>δ</i><sup>18</sup>O</span> and
<span class="inline-formula"><i>δ</i></span>D and increasing <span class="inline-formula"><i>d</i></span> (units I and III) and two others showing the
opposite trend (units II and IV). These delineate changes between episodes
of closed-system freezing with only slight recharge inversions of the water
reservoir and more complicated episodes of groundwater freezing under
semi-closed conditions when the reservoir was recharged. The water source
for pingo formation shows similarity to spring water data from the valley
with prevalent <span class="inline-formula">Na<sup>+</sup></span> and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">HCO</mi><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="33pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="eb873fe7aee1cdf217b166d877fa3e0f"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-13-3155-2019-ie00001.svg" width="33pt" height="16pt" src="tc-13-3155-2019-ie00001.png"/></svg:svg></span></span> ions. The sub-permafrost
groundwater originates from subglacial meltwater that most probably followed
the fault structures of Grøndalen and Bøhmdalen. The presence of
permafrost below the pingo ice body suggests that the talik is frozen, and
the water supply and pingo growth are terminated. The maximum thaw depth of
the active layer reaching the top of the massive ice leads to its successive
melt with crater development and makes the pingo extremely sensitive to
further warming.</p>
Creator (Dublin Core)
N. Demidov
S. Wetterich
S. Verkulich
A. Ekaykin
H. Meyer
M. Anisimov
L. Schirrmeister
V. Demidov
A. J. Hodson
Subject (Dublin Core)
Environmental sciences
GE1-350
Geology
QE1-996.5
Publisher (Dublin Core)
Copernicus Publications
Date (Dublin Core)
2019-11-01T00:00:00Z
Type (Dublin Core)
article
Identifier (Dublin Core)
10.5194/tc-13-3155-2019
1994-0416
1994-0424
https://doaj.org/article/1d1a8cdfdf8f4deca8148d271a0e189d
Source (Dublin Core)
The Cryosphere, Vol 13, Pp 3155-3169 (2019)
Language (Dublin Core)
EN
Relation (Dublin Core)
https://www.the-cryosphere.net/13/3155/2019/tc-13-3155-2019.pdf
https://doaj.org/toc/1994-0416
https://doaj.org/toc/1994-0424
Provenance (Dublin Core)
Journal Licence: CC BY