Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

Journal of the Geological Society

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by JEráBek, P. Articles by TAJcMANOVá, L. Search for Related Content GeoRef GeoRef Citation

Alpine burial and heterogeneous exhumation of Variscan crust in the West Carpathians: insight from thermodynamic and argon diffusion modelling

P. JEáBek^1,2, W.S. FARYAD¹, K. SCHULMANN³, O. LEXA^1,3 and L. TAJMANOVá^1,2

¹ Institute of Petrology and Structural Geology, Charles University, Albertov 6, 128 43, Prague, Czech Republic (e-mail: jerabek1{at}natur.cuni.cz)
² Czech Geological Survey, Klárov 3, 118 21 Praha 1, Czech Republic
³ Université Louis Pasteur, EOST, UMR 7517, 1 Rue Blessig, Strasbourg 67084, France

Phase equilibrium modelling of metagranitoids and metapelites in the MnO–Na₂O–CaO–K₂O–FeO–MgO–Al₂O₃–SiO₂–H₂O system was used to characterize Variscan and Alpine metamorphism in the crystalline basement of the Vepor Unit, West Carpathians. The calculated P–T conditions range between 570–670 °C and 6–8.5 kbar for the Variscan and 430–600 °C and 5–11 kbar for the Alpine event. These two events show contrasting metamorphic field gradients and P–T evolutions, indicating 22–27 °C km^–1 during the retrograde Variscan metamorphism and 15–18 °C km^–1 during the prograde Alpine metamorphism. The prograde Alpine metamorphism is associated with the Early Cretaceous overthrusting of the southern Gemer Unit, which resulted in apparently contemporaneous burial and horizontal ductile spreading of the underlying Vepor basement. The argon diffusion modelling was used to interpret the existing Variscan, Alpine and mixed ⁴⁰Ar/³⁹Ar cooling ages, and to constrain the T–t evolution and Alpine thermal overprint. Constructed Alpine metamorphic isograds and isotherms show horizontal P–T gradients resulting from heterogeneous exhumation of the deeper parts of the Vepor basement along two narrow belts during later folding. Here the structurally deeper metapelites form large-scale anticlinal cusp-like structures that separate structurally higher metagranitoids.