CORDIERITE-BEARING MIGMATITES FROM THE VELKA FATRA MTS., WESTERN CARPATHIANS: GEOTHERMOBAROMETRY AND IMPLICATIONS FOR VARISCAN DECOMPRESSION

Rok, strany: 1996, 359 - 365

Cordierite-bearing migmatites are found in the pre-Mesozoic crystalline basement of the Velka Fatra Mts., Central Western Carpathians as xenoliths and blocks in the granitoid pluton. Cordierite with Fe/Fe+Mg = 0.4 occurs in the assemblages with sillimanite, biotite, plagioclase, quartz, muscovite and ilmenite. Relics of spessartine-rich garnet are only sporadically preserved, replaced by cordierite porphyroblasts, therefore the origin of cordierite is related mainly to the breakdown of garnet, according to the reaction 2 garnet + 4 sillimanite + 5 quartz = 3 cordierite. On the basis of mineral composition, conventional as well as internally consistent geothermobarometry (TWEEQU method), cordierite originated at pressure conditions below 4–5 kbar and a temperature near 600 °C, as a consequence of nearly isothermal decompression. The decompressional P-T path of cordierite-bearing migmatites was associated with the rapid (ca. 2 mm/yr) emplacement of the granitoid pluton during late Variscan (342–338 Ma) time, which was most probably facilitated by tectonic extension.

ISO 690:

Janak, M., Kohut, M. 1996. CORDIERITE-BEARING MIGMATITES FROM THE VELKA FATRA MTS., WESTERN CARPATHIANS: GEOTHERMOBAROMETRY AND IMPLICATIONS FOR VARISCAN DECOMPRESSION. In Geologica Carpathica, vol. 47, no.6, pp. 359-365. 1335-0552.

APA:

Janak, M., Kohut, M. (1996). CORDIERITE-BEARING MIGMATITES FROM THE VELKA FATRA MTS., WESTERN CARPATHIANS: GEOTHERMOBAROMETRY AND IMPLICATIONS FOR VARISCAN DECOMPRESSION. Geologica Carpathica, 47(6), 359-365. 1335-0552.