Weathering of deep marine sulphide deposits in the Norwegian Sea

Title

Weathering of deep marine sulphide deposits in the Norwegian Sea

Supervisors

Ingunn Thorseth and Rolf Birger Pedersen

Project description

The increasing demand for mineral resources has led to significant interest in sulphide deposits along deep marine spreading ridges. Norway has large deep-sea areas in the Norwegian Sea, where several such sulphide deposits have been discovered over the last two decades. 
Sulphide minerals are unstable and weathered when they come into contact with oxygen-rich water. In this process, the minerals are completely or partially transformed into new, secondary mineral phases, while dissolved ions are released into the water. Weathering of sulphide minerals on land is relatively well studied. Due to a constant supply of new oxygen-rich rainwater, weathering here often leads to a continuous dissolution and runoff of acidic water with a high content of toxic heavy metals. In the marine environment, however, sulphide weathering is much less studied. Our knowledge of the mobility of heavy metals and the impact this has on the environment and the stability of mineral resources in the deep sea is therefore limited. 

The purpose of this project is to study how weathering has transformed deep marine sulphide deposits in the Norwegian Sea. The study will include mineralogical, geochemical and morphological investigations of samples from sulphide deposits along the Mohns and Knipovich Ridge, reflecting different degrees of oxidative weathering and crustal development. Relevant methods and techniques are light microscopy, scanning electron microscopy combined with X-ray analyses (SEM-EDS), X-ray diffraction (XRD), Raman spectroscopy, and ICP analyses of major, trace and rare earth elements in dissolved samples and by laser ablation (ICP-OES, ICP-MS, LA-ICP-MS).
The project provides the opportunity to work with socially relevant issues related to mineral resources in the deep sea. The student will gain experience in working with modern analytical techniques in the identification and composition of minerals, and in communication with relevant industry. The project will provide the student with expertise that is useful in private, public and academic workplaces.