FICUS, a new in-situ probe for resistivity measurements in unconsolidated marine sediments

Physical properties of shallow sediments measured at a particular site can not easily be extrapolated over a given profile. The number of samples required to define sediment properties adequately can then become time-consuming and expensive. Laboratory and in-situ experimentations have shown that el...

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Bibliographic Details
Published in:Marine geophysical researches 1998-01, Vol.20 (2), p.95-107
Main Authors: Lauer-leredde, Christine, Pezard, Philippe A, Dekeyser, Ivan
Format: Article
Language:English
Subjects:
Earth Sciences
Electrical resistivity
Marine
Marine sediments
Physical properties
Porosity
Sciences of the Universe
Sediments
Online Access:Get full text
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Summary:Physical properties of shallow sediments measured at a particular site can not easily be extrapolated over a given profile. The number of samples required to define sediment properties adequately can then become time-consuming and expensive. Laboratory and in-situ experimentations have shown that electrical probing provides a useful complementary technique to extrapolate results from cores. These experiments have pointed out the need for quantitative, easily-transportable and fast resistivity measurements combining high vertical resolution with azimuthal resolution and full coverage, in the shallow subsurface. A new prototype probe called FICUS (Formation Imaging and Coring for Unconsolidated Sediments) has been developed to bridge this gap. FICUS is designed to provide in-situ high resolution electrical resistivity images of the upper few meters of shallow unconsolidated sediments. Laboratory experiments have been completed to test the feasibility of this technique to provide resistivity images of unconsolidated sediments. Laboratory images agree with theoretical predictions from numerical modelling. The obtained cm-scale resolution could be used for petrophysical and sedimentary purposes. The probe may offer additional information about changes in porosity and pore morphology caused by climatic cycles, since electrical resistivity is known to be especially sensitive to these changes. The probe could also allow to detect and map organic pollutants in the future.[PUBLICATION ABSTRACT]
ISSN:0025-3235
1573-0581
DOI:10.1023/A:1004347505399