Hydrothermal systems, mud volcanoes, hybrid environments such as sediment-hosted hydrothermal systems and piercement structures in general are among the most spectacular geological phenomena on Earth. Several studies demonstrated that these structures play a key role in the evolution of our planet and the cycles of life during several geological eras. Active piercements are usually characterized by deep-rooted plumbing systems and complex geochemical reactions where life can adapt to thrive in extremely harsh environments making them ideal targets for deep biosphere exploration. The geophysical signals associated to such environments are often ambiguous and difficult to interpret. The elevated pore pressures often encountered at depth and the high flow rates make these structures ideal natural laboratories to capture precursors of seismic events and dynamically triggered geological processes. Piercement structures have often been reported to respond to earthquakes and external forcing.

This session welcomes contributions from geophysical, geochemical, microbial, geological, numerical and laboratory studies to promote a better understanding of modern and palaeo piercement phenomena. In particular we call for studies related to 1) investigations controlling pre-existing geological structures; 2) the geochemical reactions occurring at depth and at the surface including microbiological studies; 3) the investigation of such systems with geophysical methods; 4) experimental and numerical studies; 5) the survey and the monitoring of these settings and environments to learn the dynamics of the extinct systems from the active ones; 6) the study of palaeo piercements as well as their effects on palaeo climate.