Because microcline is the thermodynamically stable state for K-feldspar under ambient conditions, one might expect re-equilibration to a highly ordered structure to be the norm for ancient igneous complexes.
Martin, McGill University, for providing the reference microcline sample used to confirm the accuracy of our experimental procedure.
Les principaux mineraux presents sont le quartz, le feldspath plagioclase (albite-oligoclase) et la microcline
Deep drillings revealed a zone of microcline
granites and granite migmatites intruding metamorphic rocks of the granulite or amphibolite facies.
05 mm Sample Quartz Orthoclase Plagioclase Microcline
Matrix of fracture fillings Pi1 89.
It is light-grey, coarse-grained, biotite-muscovite granite containing approximately 20% microcline
phenocrysts, and is from the youngest part of the Intrusive Suite (Stewart et al.
Other soils contain significant amounts of K-bearing feldspars derived from granitic rocks of the region; XRD patterns indicate that microcline
and/or orthoclase are present in all the soils except for a few sandy soils.
Hydrothermal minerals are calcite, chlorite, albite, microcline
, epidote, opaline silica, titanite and rutile-anatase, and some sericite and clay minerals.
accounts for only some per cent of feldspars, which is a little more preserved in the albic horizon and has disappeared from the spodic horizon.
forms large (up to 12mm) phenocrysts.
The rest (20%) are grey, dotted, crystallitic b-fabric (calcareous) 2E Quartz (fresh) and few Absent plagioclases and microclines
(dotted), equant, subangular, with a bimodal distribution: 80% fine subangular sand, 20% coarse subrounded sand, random distribution 2Eg i.