RV SONNE SO318

RV SONNE - Cruise SO318

February 22 - March 26, 2026

San Diego - San Diego

Baryte venting

Barite-bearing cold seeps on the seafloor of the San Clemente Basin (California/Mexico) and their significance for fluid circulation along deep fault systems in the Earth's crust

As part of the multi-disciplinary RV SONNE expedition SO318 and its evaluation, barite-precipitated cold seeps in the San Clemente Basin, California/Mexico, will be investigated in detail. They were originally interpreted as hydrothermal formations and appear to be linked to the San Clemente strike-slip fault system, which can be traced over 100 km and is characterized by recent to sub-recent dextral movements in parallel to the San Andreas fault in the Californian border area to Mexico offshore. While fluid seeps at subduction zones and passive continental margins have been extensively studied in the past, cold seeps and their manifestations on the seafloor at sheet faults with deep-seated fluid sources have hardly been investigated so far. Elevated barium inputs throughout the San Clemente Basin are likely the result of cold seeps in this region, although the frequency of seeps, their distribution, their association with local tectonic elements of the strike-slip fault system, their structure, and thus their significance are poorly understood.