A conceptual hydrogeological model of ophiolitic aquifers (serpentinised peridotite): The test example of Mt. Prinzera (Northern Italy)

Abstract

The main aim of this study is the experimental analysis of the hydrogeological behaviour of the Mt. Prinzera ultramafic massif in the northern Apennines, Italy. The analysed multidisciplinary database has been acquired through (a) geologic and structural survey; (b) geomorphologic survey; (c) hydrogeological monitoring; (d) physico‐chemical analyses; and (e) isotopic analyses. The ultramafic medium is made of several lithological units, tectonically overlapped. Between them, a low‐permeability, discontinuous unit has been identified. This unit behaves as an aquitard and causes a perched groundwater to temporary flow within the upper medium, close to the surface. This perched groundwater flows out along several structurally controlled depressions, and then several high‐altitude temporary springs can be observed during recharge, together with several perennial basal (i.e., low altitude) springs, caused by the compartmentalisation of the system because of high‐angle tectonic discontinuities.

Hydrodynamics in Evaporate-Bearing Fine-Grained Successions Investigated through an Interdisciplinary Approach: A Test Study in Southern Italy—Hydrogeological Behaviour of Heterogeneous Low-Permeability Media

“…The isotopic composition of spring and groundwater samples did not significantly vary over time (Table 2; variations were lower than the 2 error of the 18 O and 2 H analyses), with the exception of VPS. Moreover, temporal variations were attenuated to less than 5% of that observed in the precipitation ( Figure 6), according to the observations made in other aquifer types (e.g., [46][47][48][49]).…”

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

“…The few studies conducted on ophiolitic aquifers show that the structural heterogeneities of these systems, resulting from the presence of both different lithological units and multi-scale hydraulic discontinuities (from fissure zones to kilometer-scale faults), control their inherent behavior under ambient conditions and their responses to forced conditions. 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).…”

Hydrogeological Behaviour and Geochemical Features of Waters in Evaporite-Bearing Low-Permeability Successions: A Case Study in Southern Sicily, Italy

“…), (iii) groundwater related to very prolonged pathways (>10 T.U., corresponding to at least 300 T.U. at the beginning of 1960s), the recharge of which, according to findings in other sites in Italy [64], is linked mainly to rainwater precipitated during the 1950s and 1960s, when tritium was spiked in the atmosphere by nuclear weapons testing [65], reaching up to several thousand T.U. in rainwater (e.g., [66]).…”

“…Because the vertical heterogeneity is discontinuous, it is unable to provide a continuous solution within the stratigraphic sequence over an extended area. Therefore, in contrast with other systems characterised by vertical heterogeneity, from the hydraulic point of view [64,[88][89][90], no perched aquifers overlie deeper ones, and a unique saturated zone can be assumed. Conceptual hydrogeological sketch of heterogeneous media characterised by evaporite-bearing successions.…”