|Principal investigator:||Pavol Siman|
|Investigators from institution:||Tomáš Mikuš|
PriFUK Bratislava (Marián Putiš), FPV UMB v Banskej Bystrici (Ján Spišiak)
Project deals with fluid-alteration processes in crust-mantle prism rocks exposed in alpidic orogene of the Western Carpathians, eastern Alps and northern Turkey. These processes are related to important magmatic and metamorphic events which we studied in previous projects. Now we are focussing on fluid-rock interaction zones, the genesis of which has not yet been investigated: i) in subduction-accretionary wedges blueschists, eclogites and metaultramafics, ii) in lower crust orthogneisses, granites, metabasites and metaultramafics, iii) in skarns and iv) in lamprophyres and mantle xenoliths. These processes represent a fluid-rock interaction at the different lithosphere levels. The emphasis will be given to the newly-found mineral parageneses and individual phases, which can be basis for an updated petrologic model of crust-mantle interaction. Detailed mineralogical-petrological investigation will be performed on the altered rocks mineral associations, which are the main indicators of the lithosphere fluid regime. Modern microscopic, electron-optic, rtg diffraction and spectroscopic methods will be used for determination of the alteration zones mineral and rock chemical compositions. Thermodynamic modelling and geothermobarometry will be applied for estimation alteration reactions P-T-X conditions. Chosen radiogenic and stable isotopes, and isotopic ages of alteration products will be determined. Potential sources of fluids will be defined accordingly. The lower-temperature alterations will be simulated in an autoclave; for verifying the higher-temperature and higher-pressure alteration conditions an access to special experimental laboratories abroad is required in framework of international co-operation. Model schemes of hydration-alteration processes will be proposed in microscale, with the aim to use them for geodynamic interpretation of an orogene accretionary wedge fluid regime.