Syn‐rift hydrothermal circulation in the Mesozoic carbonates of the western Adriatic continental palaeomargin (Western Southalpine Domain, NW Italy)

Evidence of hydrothermal activity is reported for the Mesozoic pre- and syn-rift successions western Adriatic palaeomargin Alpine Tethys, preserved in Western Southalpine Domain (NW Italy). The products processes are represented by vein breccia cements, as well dolomitization silicification host rocks. In eastern part study area, interpreted necking zone continental margin, Middle Triassic dolostones Lower Jurassic sediments crossed veins hydrofracturing breccias cemented saddle dolomite. precipitation dolomite cements occurred within stratigraphic succession close to sediment–water interface. Despite shallow burial depth, fluid inclusion microthermometry clumped isotopes show that fluids were relatively hot (80–150°C). hyperextended distal zone, a polyphase history host-rock fracturing recorded, with at least two generations calcite, quartz. Vein opening cementation depth around time deposition clastic succession. Fluid on both quartz indicates temperature 90–130°C, again pointing fluids. Both Fenera-Sostegno Montalto Dora areas, O, C Sr isotope values, coupled data, indicate derived from seawater interacted crustal rocks during circulation. Stratigraphic petrographic evidence, U–Pb dating dolomitized clasts sediments, document circulated through latest Toarcian, corresponding entire evolution portion palaeomargin. documented temporally correlated regional-scale thermal events took place same interval deeper levels.