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Geochemical Investigations of Hydrothermal Processes in the Hellenic Volcanic Island Arc

Objective



The objectives of the project are the:

Determination of the structural, petrochemical control on the variability of hydrothermal fluxes along the Hellenic Volcanic Arc. The formation of hydrothermal waters is associated with seawater-rock interaction processes and thus the variety of volcanic rock types associated with submarine hydrothermal exhalations along the arc play an important role in their chemical composition. Variations in hydrothermal water composition related to variations in rock composition will be determined.

Determination of the extent of the effect of hydrothermal fluxes on the bottom water composition along the Arc. The discharge of hydrothermal waters on the seafloor results in a change of the chemical composition of the bottom seawater around the vents (eg. decrease in Mg and Ca increase in Fe, Mn, decrease or increase in Na). The type and degree of this change in the bottom seawater in the different vent areas will be determined. The geographic extent of these chemical changes will also be determined in the hydrothermal areas.
Determination of the specific geochemical hydrothermal processes involved and controlling the hydrothermal fluxes along the Arc. The composition of the hydrothermal waters discharged onto the seafloor depend on the specific reactions taking place within the rocks and the sediments. These reactions will be deduced on the basis of the compositional characterisation of the hydrothermal waters and the hydrothermal precipitates.

Determination of the present day rate of hydrothermal fluxes in relation to the past. On the basis of the study of the vertical distribution of hydrothermal elements (e.g. Fe, Mn, As, Cu. Zn) in sediment cores, which will be obtained directly above hydrothermal vents, the degree of hydrothermal activity will be determined in relation to the time. The variability in the rate of hydrothermal fluxes towards the present will be deduced along the arc.
Determination of the stages of hydrothermal alteration of volcanic rocks and sediments affecting the variability in hydrothermal fluxes along the arc.
The research includes:

- Methane and CTD measurements in the entire water column in the regional surroundings of hydrothermal vents.

- Rare Earth Element determinations (e.g. La, Ce, Eu etc.) in rocks and sediments, and hydrothermal precipitates.

- Stable isotope geochemical studies (e.g. Deuterium, Oxygen, Sulfur isotopes).

- Chemical analysis of hydrothermal waters, bottom seawaters, interstitial waters, sediments and hydrothermal precipitates.

- X-ray diffraction, infra red, SEM analysis of rocks, sediments and hydrothermal precipitates.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

University of Patras
Address
University Campus
26110 Patras
Greece

Participants (1)

Freie Universität Berlin
Germany
Address
Malteserstraße 74-100
12249 Berlin