Obiettivo The oxygen isotopic composition of minerals is sensitive indicators for conditions of their formation. Until now, stable isotope studies largely have been focused on rock-forming minerals. Far less attention has been paid to accessory phases which are difficult to obtain in analytical amounts and which in many cases are difficult to decompose for isotopic analysis.Many rock - forming minerals can hardly preserve oxygen isotope ratios acquired during their formation due to later exchange processes. Preliminary results on some accessory phases (e.g. zircon) show very low mobility of oxygen and hence the potential of accessory phases to "look through" secondary processes in order to evaluate the conditions of primary processes, especially in high-grade terrains. Moreover, rock-forming minerals usually give little temporal constraints. Accessory minerals, however, frequently are the carriers of radiogenic isotopes and thus can be used to obtain age information. Therefore, an attempt to utilize different (radiogenic and stable) isotopic systems in one and the same accessory mineral could serve as a most promising tool to relate geochronological "events" with geological and petrological data.The aim of this project is to work out the base for use of accessory phases in stable isotope geochemistry. The main objectives of the planned study include(i) obtaining new data on oxygen isotopic fractionations between accessory phases and rock-forming minerals in rocks of different origin;(ii) development of new calibrations of oxygen isotopic geothermometers including accessory phases;(iii) determinations of oxygen mobility in accessory phases in relation to geological processes in comparison with mobility of elements used for dating (U-Pb, Sm-Nd, Rb-Sr).An attempt will be also made to reconstruct thermal and fluid evolution of high-grade metamorphic and ultrametamorphic Precambrian rocks (case studies from the Svecofennian Shield, South-West Greenland, East Antarctica, and the Ukrainian Shield) using oxygen isotopic distribution between accessory phases and other minerals in combination with petrological, geochronological and geochemical data. The planned studies should thus provide new insight into the origin and the time - temperature - fluid history of rocks in high-grade terrains, which in turn represent the key for the understanding of the geodynamic processes in the Earth crust. Programma(i) IC-INTAS - International Association for the promotion of cooperation with scientists from the independent states of the former Soviet Union (INTAS), 1993- Argomento(i) 5 - Earth Sciences, Environment, Energy INTAS - INTAS Invito a presentare proposte Data not available Meccanismo di finanziamento Data not available Coordinatore Universitat Bonn Contributo UE Nessun dato Indirizzo Poppelsdorfer Schloss 53115 Bonn Germania Mostra sulla mappa Costo totale Nessun dato Partecipanti (4) Classifica in ordine alfabetico Classifica per Contributo UE Espandi tutto Riduci tutto Copenhagen University Danimarca Contributo UE Nessun dato Indirizzo Oster Voldgade 5-7 1350 Copenhagen K Mostra sulla mappa Costo totale Nessun dato Institute of Precambrian Geology and Geochronology Russia Contributo UE Nessun dato Indirizzo Makarova Nab., 2 199034 St. Petersburg Mostra sulla mappa Costo totale Nessun dato National Academy of Sciences of Ukraine Ucraina Contributo UE Nessun dato Indirizzo Palladina Ave., 34 03142 Kiev Mostra sulla mappa Costo totale Nessun dato University of Lund Svezia Contributo UE Nessun dato Indirizzo Solvegatan 13 223 62 Lund Mostra sulla mappa Costo totale Nessun dato
