TDIP imaging of watershed over crystalline basement

Christian Camerlynck (1) , L Longuevergne (2) , C Roques (2)

1 SISYPHE - Structure et fonctionnement des systèmes hydriques continentaux
2 GR - Géosciences Rennes

Aquifers located in Brittany (Western France) are set over crystalline geology. Water is generally flowing through highly permeable fractures. We show the TDIP potentiality in picturing hydro-geophysical contexts. Those preliminary results need now to be confirmed by both sample measurement and in-situ characterizations. Saint-Brice-en-Cogles (Northern Brittany, N48.422°, W1.377°) The geological context comprises fractured schists with granite inclusions, located on a granite basement. Normal faults from Caledonian to Hercinian era define a horst/graben situation (Fig. 1). A borehole drilled thanks to the CASPAR program produced 43 m 3 h –1 during a preli-minary pumping test, showing the high potentiality for consumable water production. Fig. 1: Block diagram showing the aquifer situation. Fig. 2: Saint-Brice. a) Computed resistivity (Wenner-Schlumberger array, inter-electrode spacing = 3m). b) Computed chargeability (dipole-dipole array, inter-electrode spacing = 3 m).

Domains: Earth Sciences

Christian Camerlynck, L Longuevergne, C Roques. TDIP imaging of watershed over crystalline basement. 3rd International Workshop on Induced Polarization, Apr 2014, Oléron, France. 2 p., 3rd International Workshop on Induced Polarization. Abstract book. ⟨insu-01104244⟩