Naslov
Origin of amphibolites and amphibole-bearing schists of crystalline complex Moslavačka gora (Croatia)

Autori
Balen, Dražen ; Tibljaš, Darko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Journal of Conference Abstracts, vol. 4/1- Abstract Volume EUG 10 / - Strasbourg : Cambridge University Press, 1999

Skup
European Union of Geosciences (EUG) 10

Mjesto i datum
Strasbourg, Francuska, 28.03.1999. - 01.04.1999

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
amphibolites; amphibole-bearing schists; polymetamorphism; Moslavačka gora; Croatia

Sažetak
Amphibolites and various amphibole-bearing schists occur as large and small bodies and lenses within polymetamorphic amphibolite facies rock complex of Moslavačka gora (Croatia). Amphibolites are closely associated and intercalated with different types of gneisses, mica-schists, cordierite schists, homfels and marbles beeing anclaved in pre-Alpine(?) andalusite/sillimanite bearing granitoids. The crystalline complex is strongly folded and tilted and shows a fairly significant migmatization. Amphibole bearing schists containing zoned amphibole posses layered structure ("sandwich") with three different mineral associations: garnet association in "centre" of the rock (grossular-clinozoisite-clinopyroxene-plagioclase), surrounded by the clinopyroxene association (clinopyroxene-plagioclase-titanite) and embedded in the amphibole association (hornblende-plagioclase-clinopyroxene-ilmenite-quartz). A polymetamorphism is characterised by first stage metamorphic event with paragenesis metamorphosed with geothermal gradient 28-35°C/km. In the second metamorphic event intrusion of granite body caused HTLP metamorphism with geothermal gradients over 60°C/km. Tha pneumatolysis associated with granite pegmatites occurred in third phase. Changes in P-T conditions are recorded in the growth of amphibole grains (general prograde metamorphism) and changes in compositions of related paraganeses. Due to their geochemical features the amphibole-bearing rocks could be important for the correlation with other rocks of crystalline basement of Pannonian Basin in general, and especially for those from the Tisia unit. Distribution of main constituents together with distribution of minor and trace elements, petrographic data (relict textures) as well as field features observed in rock-columns suggest that protholite of amphibole-bearing rocks was: 1) basalt of oceanic tholeiite affinity for orthoamphibolitts ; 2) marls or tuffs altemating with other calcareous metasediments for paraamphibolites. This magmatic-sedimentary complex might have been partly generated in an oceanic realm and partly in arc trench and than metamorphosed in a presumed subduction zone. However to thoroughly validate this model more data are required to confirm especially the relationship between the P-T increments and the time scale.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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