(a) Diagram of δ¹³C versus δ¹⁸O including analyzes conducted in previous studies (Peckmann et al., 1999; Louis-Schmid et al., 2007; Tribovillard et al., 2013). The yellowish calcite C1 and botryoidal aragonite can be interpreted as bacterial in origin and negative isotopic values are a marker of the microbial mediation in the building of carbonate lenses. The isotopic values for C2, C3 and C4 are more dispersed with positive δ¹³C and δ¹⁸O values except for two samples that are closer to the C1 signature. The very negative δ¹³C isotopic values for C5 suggest that the same hydrocarbon-bearing fluid migrated through the tube and nodule and probably through the basal lens of sub-site A1 and all other sub-sites up to sub-site E1, but not higher as no hydrocarbons were identified above (including the sub-site R). (b) and (c) Diagrams of ⁸⁷Sr/⁸⁶Sr versus δ¹⁸O and δ¹³C versus ⁸⁷Sr/⁸⁶Sr showing three main groups. The group C1 in which the age of formation corresponds to the biostratigraphic age of the host formation (Early Oxfordian for tube T, nodule N and carbonate lenses in the sub-site A1 and Late Oxfordian for the sub-site R). The groups C2 and C3–C4 have very close Sr isotopic signatures. They formed shortly after the brecciation at a relatively shallow burial (<1000 m) with fluids coming from underlying Pliensbachian, Late Toarcian or Bajocian levels in a single migration event possibly dated of Cretaceous. The group C5 has a signature of fluids from Trias, but the migration probably occurred during the main salt diapir rising dated of the Mio-Pliocene.