SGER: A Rare Opportunity to Study Hydrothermal Activity Along an Unexplored Region of the Mid-Atlantic Ridge, 5 to 15 degrees N

Oregon State University, Corvallis OR

Investigators

Abstract

The PI will participate on a cruise aboard the German research vessel FS Sonne to collect samples on the MAR leg of the cruise as a complement to their methane sampling, through which they are hoping to identify anomalies resulting from hydrothermal activity or serpentinization. This project will study hydrothermal activity along the MAR from 5' to 15' N. Most of this section of the MAR has not been explored previously. Samples will be collected for transition element analyses including dissolved and particulate Fe and Mn. A WetLabs/SeaTech Light Scattering Sensor (LSS) will be used so that evidence of hydrothermal activity can be assessed in real time, based on hydrothermal particle anomalies in the water column. The LSS will also help in making informed decisions, based on the observation of hydrothermal particle plumes, about when to close Niskin bottles for sample collection. The MAR between 5' and 15'N is host to large fracture zones, where ultramafic exposures are likely to be found. It is possible that active hydrothermal sites occur within a ridge offset in this region, in a setting similar to that which is host to the Rainbow hydrothermal site at 36'16'N on the MAR. The Rainbow site shows extremely high concentrations of hydrothermal particles in the water column, along with methane anomalies, so if a similar venting system exists within the 5' to 15'N region of the MAR, we will undoubtedly observe the hydrothermal anomaly in one of the above tracers.