Application of Chlorite Compositional Geothermometres to Hydrothermal Veins in the Variscan Flysch Sequences of the Nízký Jeseník Upland, to Alpine-type Veins

Chlorites from (1) hydrothermal veins composed of quartz and/or carbonate that cross-cut unmetamorphosed to epizonally metamorphosed Variscan flysch sequences in the Nízký Jeseník Upland, (2) Alpine-type veins in amphibolites and gneisses of the Sobotín region, and (3) pegmatites of the Žulová massif and Strzegom-Sobótka massif were studied by chemical methods to elucidate the conditions of their formation. All analyzed chlorites belong to the clinochlore-chamosite solid solution series. Six various geothermometers were applied which are based on the number of octahedral vacancies, the number of tetrahedral Al and the value Fe/(Fe+Mg). Geothermometers of Cathelineau & Nieva (1985), Kranidiotis & MacLean (1987), and Zang & Fyfe (1995) yielded temperatures of formation of the chlorites that range from 167 to 300 °C (chlorites of Group 1), from 161 to 298 °C (Group 2) and from 164 to 308 °C (Group 3).