Fracture controlled permeability of ultramafic basement aquifers. Inferences from the Koniambo massif, New Caledonia

Review: Hydrogeology of weathered crystalline/hard-rock aquifers—guidelines for the operational survey and management of their groundwater resources

“…In foliated rocks, the fracturing intensity is maximum where the foliation is subvertical, whereas it decreases and reaches a minimum where the foliation is subhorizontal. Peridotites, which are considered as HR by several authors, can form good aquifers; however, they show a dual aquifer behavior, pseudo-karstic and fractured (Dewandel et al 2005(Dewandel et al , 2017cJoin et al 2005;Jeanpert et al 2019).…”

Groundwater flow characterization of an ophiolitic hard-rock aquifer from cross-borehole multi-level hydraulic experiments

“…Ophiolitic rocks are fragments of oceanic crust and upper mantle which are widespread on the surface of continents along tectonic suture zones (e.g., Abbate et al, 1985;Boronina et al, 2005;Maury and Balaji, 2014;Segadelli et al, 2017b;Vacquand et al, 2018;Jeanpert et al, 2019). These rocks extend from the Alps to the Himalayas through, for instance, Cyprus, Syria and Oman, and are also present in various countries such as Cuba, USA, Papua-New Guinea, New Caledonia and Newfoundland (Abbate et al, 1985).…”

“…The presence of structural discontinuities that control the permeability of these systems results in some similarities with the well-known and widely-studied fractured granitic rock aquifers. However, these similarities in terms of fracturation do not result in similar overall systems since the submarine conditions of formation of ophiolitic rocks and weathering after exumation lead to complex hydrogeological properties that are not well characterized yet (e.g., Boronina et al, 2003;Dewandel et al, 2005;Jeanpert et al, 2019). For instance, at meter to tens of meters scales, far from faults, hydraulic discontinuities in peridotites are often zones concentrating high density of fissures whereas granite systems are usually homogeneous, poorly-permeable matrix hosting pluri-meter scale, often sparsely distributed, discrete fractures.…”

“…As a result, the hydrogeological models that are built to understand and reproduce the hydrodynamic of these aquifers are based on the coexistence of various recharge and transmissivity zones, which hydraulic properties depend on the lithological units and discontinuities that are associated with the zones (e.g., Boronina et al, 2003;Dewandel et al, 2005;Segadelli et al, 2017a). These properties are estimated from different characterization techniques, including hydrograph analysis, mercury porosity and hydraulic conductivity laboratory measurements, as well as pumping tests (e.g., Boronina et al, 2003;Dewandel et al, 2005;Jeanpert et al, 2019).…”

“…In the context of ophiolitic aquifers, only a few studies considered pumping tests for characterizing these hydrosystems (e.g., Boronina et al, 2003;Dewandel et al, 2005;Jeanpert et al, 2019). For the Kouris catchment in Cyprus and the Koniambo massif in New Caledonia, hydraulic conductivity estimates were obtained from single-borehole pumping experiments and packer tests, respectively, that are interpreted with simple analytical solutions (Boronina et al, 2003;Jeanpert et al, 2019). For the ophiolite hardrock aquifers in Oman, the interpretation of open cross-borehole pumping experiments with a dual-porosity (or dual-permeability) model led to estimate the hydraulic conductivity and storage coefficients at various locations (Dewandel et al, 2005).…”