RV POSEIDON Cruise Nº 402

Abstract

Menez Gwen is a ridge-centred seamount with neovolcanic and hydrothermal activity at 37°N on the Mid-Atlantic Ridge (MAR). Menez Gwen was discovered 1994, and although it was visited by submersible dives in subsequent years it remains one of the least investigated hydrothermal vent fields on the northern MAR. The Menez Gwen hydrothermal vent field was chosen as a key study site for interdisciplinary geological, chemical and biological studies within the Research Area F “Lithoshpere – Biosphere Interactions” of the MARUM Cluster of Excellence. This cruise served as a base line study for a follow up cruise with RV METEOR and the ROV Quest and focused on two major questions: 1) What is the volcanic activity at Menez Gwen? and 2) Are there more active vent sites than previously described and did the hydrothermal activity on the young volcano in the rift graben change since 1997? To achieve these goals we followed two strategies: High resolution bathymetric mapping using ship based and AUV based echosounders and tracking of the neutral buoyant hydrothermal plume with CTD/MAPR profiles.