Search results for "Clinozoisite"
showing 3 items of 3 documents
?Short Distance?-Variabilit�t der Na-Gehalte niedrigmetamorpher mit Albit ber�hrungsparagenetisch koexistierender Hellglimmer
1973
White micas coexisting with albite, quartz, chlorite, and clinozoisite in low-grade schists of the Beaume Valley (Massif Central, France) have been analyzed by standard microprobe techniques. As the micas of an albite-rich thin section show significantly higher Na-contents than those of an albite-poor one of the same rock sample, the application of the muscovite-albite-geothermometer results in inconsistent temperature values. Thus the analyses may indicate that the distribution of sodium between coexisting white micas and albite not only depends on temperature and pressure but also on the chemical potentials of the alkalies in the metamorphic fluid phase.
Eine Subfaziesfolge der Grünschieferfazies in den Mittleren Cévennen (Dép. Ardèche) mit Pyrophyllit aufweisenden Mineralparagenesen
1969
In the middle part of the Cevennes, situated at the south-eastern border of the Massif Central, there are outcrops of micaschists, gneisses and granites in which the increase of metamorphic grade was investigated along the river Beaume. This paper presents the results of the petrographic-geochemical analysis of the micaschists of the greenschist facies. Chemical analyses of the micaschist-samples examined petrographically show their nearly constant composition, a fact which e.g., is expressed by similar CaO/Na2O- and MgO/FeO-proportions. As the average values of the determined oxides approach the respective average values of analyses of graywackes recorded by Pettijohn (1957) the original s…
Phase equilibria modelling of retrograde amphibole and clinozoisite in mafic eclogite from the Tso Morari massif, northwest India: constraining the P…
2014
Phase equilibria modelling of post-peak metamorphic mineral assemblages in (ultra)high-P mafic eclogite from the Tso Morari massif, Ladakh Himalaya, northwest India, has provided new insights into the potential behaviour and source of metamorphic fluid during exhumation, and constrained the P–T conditions of hydration. A series of P–M(H2O) pseudosections constructed in the Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–O (NCKFMASHTO) system show that a number of petrographically distinct hydration episodes occurred during exhumation from peak P–T conditions (~640 °C, 27–28 kbar), resulting in the formation of abundant compositionally zoned amphibole and minor clinozoisite poikiloblasts at the exp…