Archive
Article
Geologica Carpathica, 1996, vol. 47, no. 4
KYANITE-MAGNESIAN CHLORITE SCHIST AND ITS PETROGENETIC SIGNIFICANCE (THE SINEC MASSIF, SOUTHERN VEPORIC UNIT, WESTERN CARPATHIANS)
Abstract
The Alpine metamorphic assemblage Mg-chlorite (Al-sheridanite)–kyanite–tourmaline (dravite) (quartz, muscovite was formed by transformation of an aluminosilicate rock (probably granite) during the process of Mg-metasomatism. The kyanite ? a mineral of scarce occurrence within the crystalline rocks of the Veporic Unit, formed in an Al-Mg saturated system. The development of mineral assemblage presumed to occur at 350–420 °C under lower to medium pressure conditions (approx. 2.3–4 kb), has been prompted by the effects of allochemical metasomatism, bound spatially to the steatitization and hydrolysis of magnesite. The whole rock and mineral geochemistry indicates an increase in contents of Mg, Al, H2O, P, Fe, Li, Ga, LREE and decrease in Si, Na, K, Ca, Rb, Ba and HREE. The tectonized and hydrothermally altered zone, characterized by occurrence of kyanite, formed during Alpine reactivation of the Veporic basement. Possible reasons to explain the lower degree of the Mesozoic cover metamorphism as well as remarkable affinity of some of the overlying Gemeric Carboniferous metamorphosed rocks to the investigated metamorphic assemblage are discussed.
Pages:
245 - 255
Published online:
0. 0. 1996