Shearzone related talc mineralizations; evidences from a multi-analytical approach
Research output: Thesis › Doctoral Thesis
Shear zones are zones of enhanced fluid flow and may act as pathways for mineralizing fluids. The occurrence of talc may be related to such shear zones. To discerne the mechanism and characteristics of these shear zone related talc mineralization, several talc deposits related to major fault zones were chosen: the magnesite and talc deposits of the Eastern Greywacke Zone, in the Eastern Alps in Austria i.e. Veitsch, Wald am Schoberpass and Lassing, further the Gemerska Poloma talc deposit in Slovakia and the Sardinian talc deposits Sa Matta and Su Venosu. In the investigated deposits talc mineralization occurs within Mg-carbonate hostrocks. Geochemical analysis, stable isotopes and fluid inclusion study were performed to yield indications on kind, origin, temperature and timing of the talc mineralizing fluid. In addition, (U-Th)/He measurements were applied at the Sa Matta talc deposit to yield information on the age of the talc formation. The study of the deposits of the Eastern Greywacke Zone shows how temperature and deformation features increase with growing proximity to the fault zones and that these features can be related here to the formation of talc. Investigations of the Gemerska Poloma talc deposit show the transfer of stress and fluids that were activated during fault slip affected the magnesite body and induced talc mineralization. The (U-Th)/He dating of the talc-chlorite event indicates that the hydrothermal event that led to the mineralization is at least 75 Ma. This is an important indicator that the talc mineralization took place before the activiation of the alpine Nuoro-fault. This study has given insights on the role of fault zones as fluid pathways and the enrichment of talc resulting from deformation along fault zones.
|Translated title of the contribution||Scherzonengebundene Talkmineralisationen; Belege aus einem Multimethoden Ansatz|
|Publication status||Published - 2014|