Centre for Deep Sea Research

Hydrothermal influence on rocks in fault zones at Mohn's Ridge

Msc project of Synne Langelo Wågbø

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Project title

Hydrothermal influence on rocks in fault zones at Mohn Ridge


Rolf B. Pedersen, Håvard Stubseid, Anette B. M. Tvedt (ADepth), Ebbe Hartz (Aker BP)

Project description

The Center for Deep Sea Research has identified several hydrothermal fields along the Mohn Ridge. Hydrothermal activity at spreading ridges is driven by heat from magma, and the hydrothermal circulation of water is largely channeled along fault zones. Rocks along fault zones will therefore be affected to varying degrees by hydrotermal activity. Petrological and geochemical studies of rock samples from fault zones could provide new information about the extent of water-rock interactions and knowledge about the fluids that have affected the rocks. 

This master´s project will involve the investigation of core samples to be collected during a research expedition to the Mohn Ridge in April-Mail 2023. The main goal is to study water-rock interactions at one or more fault zones that are planned to be drilled with a new bottom-based drilling rig (Flexicore), which will be operated from one of DeepOcean´s subsea vessels. The main supervisor is the scientific leader of the expedition. Using an ROV, the Center for Deep Sea Research has already collected sample material from several fault zones in this area. These will also be analyzed as part of this study, and this material will ensure access to relevant samples if the drilling operations fail. 

The degree of water-rock interactions along the fault zones will be studied using Sr-Nd isotopes and rock/mineral chemical analyses. The mineralogy and mineral chemistry of fracture mineralizations and any more massive mineralizations that occur at fault zones will also be studied. These studies will be conducted using light/electron microscopy and Raman spectroscopy and laser ablation-ICP-MS based element mapping and point analysis. Temperature and composition of fluids that have formed mineralizations will be determined by fluid inclusion analysis.