TDIP imaging of watershed over crystalline basement
Abstract
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
Origin : Files produced by the author(s)