First Nautile dive

Located in the axial zone of the ridge, the objectives of this first dive were to carry out routine tests of the Nautile on the seabed, and to explore a recent volcanic zone and possibly find an associated hydrothermal site.

This first dive showed that the seabed consists mainly of lava flows with very little sediment cover and so fairly recent. Their morphologies vary from rather rounded pillow lava to more elongated and lobed lava. The external glass crust is still frequently present and testifies to the freshness of the lava. A multitude of sponges were also observed at the beginning of the dive.

The four samples collected will now be cut, described and prepared by the rock team for initial chemical and mineralogical analyses.

 

On Thursday night, a CTD operation showed anomalies in the water column for turbidity, methane and manganese.

After the dive, the vessel returned to the area where the anomalies were measured to perform a Yoyo profile overnight. The aim of this type of profile is to lower and raise the CTD while the vessel advances at slow speed in a given water depth (in this case between 2900 and 3500 m). This grids the area where the anomaly has been detected and maps the chemistry of the hydrothermal plume.