chloritoid is crystallised with chlorite, white mica and garnet in chlorite zone metapelites ofthe regional metamorphic rocks of the sanandaj-sirjan metamorphic belt in southern iran. chemistry ofcoexisting minerals is studied using microprobe analysis. application of the chlorite-chloritoidgeothermometry gives temperatures of 515°c and 557°c. the chlorite-garnet fe-mg exchangegeothermometer in...

Rocks from the Valhalla metamorphic core complex, British Columbia, Canada, have experienced granulite Jades metamorphism at conditions of 820±30°C, 8±1 kbar. Peak metamorphism was accompanied by dehydration melting of muscovite, but not biotite, followed by minor back reaction of garnet + K-feldspar + H20sillimanite + biotite+plagio close.' At conditions very near those of the peak, extensive ...

Studies of chemical compositions and grain size garnet in a quartzo-feldspathic gneiss from the Lützow-Holm Complex at Skallen, East Antarctica, form basis an interpretation timing homogenization. The contains only as mafic minerals except sporadic biotite inclusions garnet. represents approximately constant Mg/(Fe+Mg) within grain. values small grains are higher than those large grains, while ...

Abstract The reliability of eight Fe–Mg exchange geothermobarometers for garnet-bearing peridotites, pyroxenites and eclogites has been examined using a database comprised more than 300 published peridotite, pyroxenite eclogite experiments conducted from 10 to 70 kbar 850 &gt; 1650 $$^\circ{\rm C}$$ <mm...

Temperature estimates obtained with various biotite-garnet thermometers are inconsistent in granulite facies rocks. Although the inconsistency lies partly in the lack of definition of equilibrium criteria, it still remains after rigorous selection of analyzed mineral pairs (isolated biotite and garnet cores for peak equilibrium conditions) and originate from minor element effects in garnet and ...

Abstract The temperature-dependent exchange of Ni and Mg between garnet olivine in mantle peridotite is an important geothermometer for determining temperature variations the upper diamond potential kimberlites. Existing calibrations Ni-in-garnet show considerable differences estimated above below 1100 °C hindering its confident application. In this study, we present results from new synthesis ...

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...