Coexisting chloritoid and staurolite
نویسندگان
چکیده
منابع مشابه
The occurrence of paragonite in chloritoid schists from Stonehaven, Scotland
Paragonite has been found in two chloritoid-chlorite-mica schists from the Dalradian, north of Stonehaven. The principal bulk-chemical constraints on the occurrence of this mineral within the chloritoid zone appear to be the ratios of soda to potash and the A1203 contents of the rock. The composition of paragonite coexisting with muscovite indicates a crystallization temperature of 550 ~ for ro...
متن کاملThe staurolite enigma solved.
Staurolite has been long considered an enigma because of its remarkable pseudosymmetry and the frequent twinning. Staurolite gives two twins whose occurrence frequency seems to contradict the condition of lattice restoration requested by the reticular theory of twinning, in that the more frequent one (Saint Andrews cross twin) has a twin index of 12, whereas the less frequent one (Greek cross t...
متن کاملDistribution of Fe and Mg between garnet and biotite in Scottish Barrovian metamorphic zones
The distribution coefficient KD=(Mg / Fe)garnet/(Mg/Fe)biotite has been calculated for eight garnet-biotite pairs from rocks ranging from the garnet isograd to the staurolite zone along the Stonehaven coast of NE Scotland. This distribution coefficient depends upon metamorphic temperature and is not dependent upon the Mn and Ca content of garnet. Garnet-biotite geothermometer yields temperature...
متن کاملDefects along kyanite-staurolite interfaces
The note describes (100) stacking faults in kyanite from a staurolite-kyanite intergrovrth with a displacement vector R : 7zb. Di-ffraction spots k * 2n are streaked and only with those reflections stacking faults are in contrast, which is interpreted as due to a displacement of thb on the,(100) faults. This produces groups of two corner-sharing tetrahedra. If stacking faults occur periodically...
متن کاملPhase relations and reaction histories of chloritoid-free and chloritoid-bearing metapelites from the Mahneshan area, NW Iran
Mineral assemblages, reaction textures and mineral composition of the metapelitic rocks from the Mahneshan area in NW Iran are studied to reconstruct the reaction history of the rocks. The phase relation on the real mineral chemistry AFM, AFMn compatibility diagrams and mineral isograds in chloritoid-free and chloritoid-bearing metapelites of Mahneshan Complex were studied in order to determine...
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ژورنال
عنوان ژورنال: Geological Magazine
سال: 1972
ISSN: 0016-7568,1469-5081
DOI: 10.1017/s001675680003778x