Origin of K-cymrite and kokchetavite in the polyphase mineral inclusions from Kokchetav UHP calc-silicate rocks: evidence from confocal Raman imaging
Mikhno, Anastasia O.; Schmidt, Ute; Korsakov, Andrey V.
European Journal of Mineralogy Volume 25 Number 5 (2014), p. 807 - 816
published: Jan 3, 2014
ArtNo. ESP147052505011, Price: 29.00 €
Confocal Raman Imaging revealed the coexistence of kokchetavite and K-cymrite (KAlSi3O8H2O) in association with muscovite/phengite, lollingite, calcite and a -cristobalite in polyphase mineral inclusions in clinopyroxene of calc-silicate ultrahigh-pressure metamorphic (UHPM) rocks from the Kokchetav Complex (northern Kazakhstan). Experiments have shown that K-cymrite is stable under high pressure conditions; however, this phase never had been reported from UHPM rocks before. The mode of occurrence of K-cymrite and kokchetavite in these rocks is strong evidence for kokchetavite formation through the dehydration of K-cymrite. The presence of fluid inclusions and K-cymrite in the polyphase mineral inclusions testify for water-saturated conditions in the rock-forming environment near peak metamorphic conditions.