Open doctoral projects

Earth and Marine Sciences

Petrology and geochemistry of altered peridotites in the oceanic lithosphere: the role of ultramafic rocks alteration in the ore forming processes

Altered upper mantle rocks (peridotites) at slower-spreading ridges on the ocean floor constitute highly reactive chemical and thermal systems. Interaction of peridotites with seawater to produce serpentinites has major geological consequences, namely in terms of heat production that can contribute to hydrothermal circulation. Talc metasomatism of serpentinized peridotites (fluid-rock reactions with Si-addition and Mg-removal from the serpentinized peridotite) has been also reported along these geological settings. However, less is known about the contribution of these reactions in the formation of Seafloor Massive Sulfide (SMS) deposits. When associated with SMS deposits, these altered rocks commonly accommodate sulfide mineral assemblages. This research project is based on the petrological and geochemical study (including isotopic geochemistry) of seafloor rock samples, and associated ore deposits, collected at the Mid-Atlantic Ridge. It aims to investigate the role of seafloor mantle rocks alteration in the formation of SMS deposits. For this, state-of-the-art techniques in mineralogy and geochemistry will be applied. The outcomes of this doctoral project are expected to be published in peer-reviewed papers and international conferences. 

SUPERVISOR: Ágata Alveirinho Dias –


KEYWORDS: petrology, mineralogy, ore deposits, submarine hydrothermal processes