Field Investigation of Serpentinite With Induced Polarization and the K‐Means Clustering Technique
Abstract
We performed a field induced polarization survey at Rocher du Chateau in the French Alps. This site is characterized by the presence of ophiolites with an outcrop of serpentinites. Serpentinite is characterized by high resistivity (∼0.5-10 kΩ m) and high chargeability (∼20-400 mV V 1 ) values. We collected two serpentinite core samples for spectral induced polarization measurements conducted in the frequency range 10 mHz-45 kHz, validating the field results. The high chargeability of serpentinite is associated with the production of magnetite during the fluid-rock alteration, as indicated by the high magnetic susceptibility of the core samples (0.0340 SI). Using the laboratory measurements and the K-means clustering technique, we successfully imaged the serpentinite facies and we were able to distinguish blocks of serpentinites embedded in the sedimentary cover. This approach could possibly be used for the seafloor exploration using induced polarization.
Plain Language Summary Induced polarization is a non-invasive geophysical method known to be sensitive to the presence of semi-conductors. Serpentinite is formed through the alteration of peridotites, resulting in the formation of magnetite, which, in addition to its magnetic properties, is responsible for a strong chargeability. The presence of an ophiolite in the French Alps provides an exceptional opportunity to study onshore the induced polarization response of peridotites, and especially serpentinite. The results obtained in this paper may prove to be useful for the exploration of the oceanic seafloors by documenting the properties of such materials.
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