Paper Title :Combined Use of Land Gravity Data and 3D Geological Model to Image Deep Geological Basin: Case of Region of La Broye, Switzerland
Author :Guillaume Mauri, Laurent Marguet, Gunnar Jansen, Urs Marti, Roland Baumberger, Robin Allenbach, Pascal Kuhn, Pierrick Altwegg, Stephen A. Miller
Article Citation :Guillaume Mauri ,Laurent Marguet ,Gunnar Jansen ,Urs Marti ,Roland Baumberger ,Robin Allenbach ,Pascal Kuhn ,Pierrick Altwegg ,Stephen A. Miller ,
(2017 ) " Combined Use of Land Gravity Data and 3D Geological Model to Image Deep Geological Basin: Case of Region of La Broye, Switzerland " ,
International Journal of Advances in Science, Engineering and Technology(IJASEAT) ,
pp. 75-81,
Volume-5, Issue-2
Abstract : Over the last decade, in Switzerland, geothermal projects target deeper structures in hope to find potential
geothermal resources to produce electricity. Among the deep geological features, deep Permo-carboniferous basins could
host large geothermal reservoirs. The region of La Broye, in the western molasse plateau in Switzerland, was investigated to
confirm the existence of such deep structures. The aim of the study is to bring new insight on the origin of the gravity
variations in the region of La Broye. Reprocessing of previous gravity data set has improved the resolution of gravity
decrease associated to the basin of la Basse-Broye that is made of moraine and post glacial deposits. Over 100 km2, we
surveyed 824 new gravity stations. Then, a 2 mGal gravity decrease long of 10km has been well defined, which is located
over the molasse hills, between Neuchâtel Lake and the plain of Basse-Broye. A 2D sensitivity study using a 2D geological
model from seismic atlas shows that observed gravity decrease over the hills cannot be associated to rock density variation
from either shallow layer from post ice age period, or sedimentary layer from Mesozoic period. However, the 2D model was
inconclusive for a deep structure source. The 3D forward gravity model computed using Swisstopo 3D geological model
provide clear information that only a deep structure can generate the observed gravity decrease. Shape of this deep structure
has been estimated through 3D forward gravity model, by doing a stripping of the gravity effect associated to each formation
for geological layers from the Tertiary, Quaternary and Mesozoic periods. Finally, based on its location and extend, the
source of the gravity variations over the hills can only be a deep Permo-carboniferous basin.
Type : Research paper
Published : Volume-5, Issue-2
DOIONLINE NO - IJASEAT-IRAJ-DOIONLINE-7928
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Published on 2017-06-28 |
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