Dear All
I am working on metamarls (calcareous metaschists/impure marbles etc.)
including K-micas under high pressure (~25 kb) - medium to high grade
conditions, and hence are looking for places where it would be possible to
sample such rocks.
I'm in particular interested in the buffering of the Tschermak's exchange
across the transition phlogopite-phengite (biotite-muscovite) in metamarls,
and therefore searching for spots from where equlibrium between these micas
are described or just mentioned and where it is possible to recognize a
metamorphic development in adjoining rocks.
Two adjoning layers of metamarl with separate biotite and phengite (or akin
minerals that will buffer the Tschermak's exchange) also have my interest,
as long as a visible metamorphic development is present and not influenced
to much by retrograde non-equilibrium overprints or external metosomatic
episodes.
If you know about any locations or references, I would very much appreciate
your help.
Thanks in advance
Regards
/Tonny B. Thomsen
Institute of Mineralogy and Petrography
Swiss Federal Institute of Technology (ETHZ)
Zürich, Switzerland
E-mail: [log in to unmask]
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