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| Titel |
Transboundary geophysical mapping of geological elements and salinity distribution critical for the assessment of future sea water intrusion in response to sea level rise |
| VerfasserIn |
F. Jørgensen, W. Scheer, S. Thomsen, T. O. Sonnenborg, K. Hinsby, H. Wiederhold, C. Schamper, T. Burschil, B. Roth, R. Kirsch, E. Auken |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 7 ; Nr. 16, no. 7 (2012-07-04), S.1845-1862 |
| Datensatznummer |
250013353
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| Publikation (Nr.) |
 copernicus.org/hess-16-1845-2012.pdf |
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| Zusammenfassung |
| Geophysical techniques are increasingly being used as tools for
characterising the subsurface, and they are generally required to develop
subsurface models that properly delineate the distribution of aquifers and
aquitards, salt/freshwater interfaces, and geological structures that affect
groundwater flow. In a study area covering 730 km2 across the border
between Germany and Denmark, a combination of an airborne electromagnetic
survey (performed with the SkyTEM system), a high-resolution seismic survey
and borehole logging has been used in an integrated mapping of important
geological, physical and chemical features of the subsurface. The spacing
between flight lines is 200–250 m which gives a total of about 3200 line km.
About 38 km of seismic lines have been collected. Faults bordering a
graben structure, buried tunnel valleys, glaciotectonic thrust complexes,
marine clay units, and sand aquifers are all examples of geological
structures mapped by the geophysical data that control groundwater flow and
to some extent hydrochemistry. Additionally, the data provide an excellent
picture of the salinity distribution in the area and thus provide important
information on the salt/freshwater boundary and the chemical status of
groundwater. Although the westernmost part of the study area along the
North Sea coast is saturated with saline water and the TEM data therefore
are strongly influenced by the increased electrical conductivity there,
buried valleys and other geological elements are still revealed. The mapped
salinity distribution indicates preferential flow paths through and along
specific geological structures within the area. The effects of a future sea
level rise on the groundwater system and groundwater chemistry are discussed
with special emphasis on the importance of knowing the existence,
distribution and geometry of the mapped geological elements, and their
control on the groundwater salinity distribution is assessed. |
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