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| Titel |
An investigation of heterogeneous water flow and transport processes in an oxidized glacial till using environmental isotope profiles |
| VerfasserIn |
Christine Stumpp, M. Jim Hendry |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250040984
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| Zusammenfassung |
| The heterogeneity of flow and transport processes of a surficial glacial till in Southern
Saskatchewan, Canada, was investigated using environmental isotopes. This study focused on
the variable flow conditions of the upper 6m of the clay rich till. This depth covered the
transition between oxidized (0-4m) and unoxidized (4-6m) sediments and was subject to
seasonal water table fluctuations (1-3m). Continuous core samples of three vertical depth
profiles in a distance of maximal 65m were taken three times a year. Grain size distribution,
bulk densities, and water contents were analyzed in the drilled cores. Additionally, transient,
high-resolution (0.2m) profiles of δ18O and δ2H in pore waters were measured
using a H2O(liquid)-H2O(vapor) pore water equilibration and laser spectroscopy
technique.
The depth profiles of the grain size analysis, water contents and bulk densities clearly
indicated a highly heterogeneous structure in the upper 6m. This complex system
was supported by the spatial distribution of the water isotopes resulting in three
distinct, different isotope depth profiles. The temporal distribution of the isotopes
in the pore waters indicated variable up- and downward fluxes in the upper two
meters. Below, the flow was almost stagnant and diffusion was the dominating
transport process. The water table fluctuations were not influencing the isotope
contents.
Assuming equilibrium flow and transport processes it was possible to describe one
of the three profiles. The other two were influenced either by fractured flow or
by lateral flow processes in different depths favoring winter infiltration to greater
depth.
It was shown that the combination of water contents, sediment properties, and water
isotopes were able to identify the significantly heterogeneous flow and transport processes in
a glacial till. |
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