geothermometer to a staurolite-grade schist from Sulitjelma, north Norway
SUMMARY. The occurrence of coexisting paragonite (containing 0"70 % CaO) and muscovite (con-taining o.i6 % CaO) in a staurolite-grade paragonite-muscovite-hornblende-garnet-biotite schist from Sulitjelma enables an estimate to be made of the temperature of recrystallization, using an extension,...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.623.6043 http://www.minersoc.org/pages/Archive-MM/Volume_37/37-290-693.pdf |
| Summary: | SUMMARY. The occurrence of coexisting paragonite (containing 0"70 % CaO) and muscovite (con-taining o.i6 % CaO) in a staurolite-grade paragonite-muscovite-hornblende-garnet-biotite schist from Sulitjelma enables an estimate to be made of the temperature of recrystallization, using an extension, based on crystal chemistry considerations and available analyses of muscovites and paragonites from metamorphic rocks, of the experimentally determined solvus in the K-Na white mica system into the Ca-K--Na system. This temperature of recrystallization is approximately 55o-7 ~ ~ and is consistent with the experimental data on the coexistence of staurolite and quartz in the system Fe-A1-Si-O-H (Richardson, I968). I N recent years paragonite has been recorded in an increasing variety of metamorphic rocks. It has commonly been found to coexist, at low to medium grades of meta-morphism, with one or more of the following minerals: muscovite, chlorite, biotite, chloritoid, almandine, staurolite, and kyanite; and more rarely with andalusite, glaucophane, or actinolite (Harder, I956; Zen and Albee, 1964; Guidotti, I968). To the writer's knowledge, however, the only occurrences of paragonite coexisting with hornblende are those recorded by Banno (I 96o) from the Bessi district, Sikoko, Japan: |
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