152 A new concept of karst development based on hydrogeology and geophysics comparison with geological outcrops in the Clain Valley (Branger et al., 2026). Dating of sedimentation across the Poitou Threshold (Fig. 1) remains difficult, as ammonite occurrences are rare and largely restricted to the base of the depositional sequence (Gabilly, 1978, p. 150). Consequently, stratigraphic interpretation relies primarily on the identification of erosional surfaces (Gabilly et al., 1985), bed thickness, fossil assemblages, and established regional reference sections (Gabilly, 1978; Mourier et al., 1986). This study is based on the analysis of two continuous cores (C1 and C2) and highresolution borehole optical imagery (OPtical TeleView - OPTV). Figure 1 shows the location of the HES, the core drillings, and the Mignaloux borehole described by Mourier (1983). Aquifer stratigraphy of the HES Stratigraphic context The reference stratigraphy for the supra-Toarcian aquifer is derived from the works of Gabilly (1978), Benvel (1978), and Mourier (1986). For further details about Figure 1 The hydrological experimental site and borehole locations (Poitiers University document).
RkJQdWJsaXNoZXIy NjA3NzQ=