Abstract
The paper presents authors’ data on mineral assemblages in rocks of olistostrome melange in the northern part of the Vardar zone in the Fruska Gora Range, Serbia, Balkan Peninsula, which were affected by metamorphism to low grade of the glaucophane-schist facies in relation to Late Jurassic-Early Cretaceous subduction. The olistostrome is dominated by phengite-chlorite-quartz metasandstones and glaucophane-bearing metabasalts, with the latter rocks containing an equilibrium association of zonal riebeckite-glaucophane amphibole, chlorite, pumpellyite, actinolite, and epidote. The Na-amphibole is commonly zonal and has riebeckite cores and glaucophane outermost zones. The metasandstones contain phengite rich in Si (3.45 f.u.) and Mg (0.40 f.u.), which can be formed only under high pressures. The composition of the phengite and the position of glaucophane-pumpellyite-bearing mineral assemblages from the Fruska Gora Range in the P-T grid for low-temperature metabasites indicate that the culmination of subduction-related metamorphism occurred at T − 340–350°C, P = 4−8 kbar, which corresponded to a depth of 14–29 km. Comparison with certain typical glaucophane-bearing complexes shows that the Rbk → Gln zoning of the Na-amphiboles develops in the course of prograde metamorphism. The zoning of Na and Na-Ca amphiboles of the riebeckite-glaucophane-winchite-barroisite series is proved to be, along with zonal garnet crystals, a sensitive indicator of prograde high-pressure transformations in metabasites in the low-temperature region and can be utilized to distinguish between metamorphic zones and subfacies in glaucophane schist complexes.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.