Prior to its Miocene extension, the Pannonian Basin was characterized by a thick crust, which is represented by garnet granulite xenoliths in the Bakony-Balaton Highland Volcanic Field. We followed the processes which occured in the rock on crustal xenoliths from Sabar-hegy and Szentbékkálla by the means of petrography, mineral equilibria, geothermobarometry and fluid inclusion studies. From this we could conclude to the p-T changes, which took place in the lower crust during the extension. According to our results the thickness of the crust was 48-55 km prior to the extension and at about 30 km after it. It follows that the crustal thinning factor was β = 1.6-1.8, which confirms the results of HUISMANS et al. . We have shown 100-300 °C temperature rise in the lower crust during the extension. The temperture could reach 1170 °C. In addition we proved that CO2-rich fluids dominated the lower crust before and after the extension too. Our results on the process and scale of crustal thinning are based on methods used in metamorphic petrology, which are independent on tectonical and geophysical methods used for modelling of basin evolution, so they can be adapted for controlling and refining extensional models of the Pannonian Basin.
|Number of pages||9|
|Publication status||Published - Dec 1 2003|
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