Astrobiological implications of chaos terrains on Europa to help targeting future missions

► Chaos terrains give more information on possible submarine volcanism than other surface structures. ► Analysis of blocks at Conamara Chaos suggests that the ice was 2 km thick at the rafts during chaos formation. ► The ice at the low level matrix between the rafts was 0.5 km thick during chaos formation. ► Submarine volcanic gas released might form bubbles as clathrate decompose close to the surface. ► These bubbles may have been trapped and thus observed close to the chaos terrains.