amphibolite facies


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Related to amphibolite facies: Blueschist Facies, Granulite Facies, Metabasites

amphibolite facies

[am′fib·ə‚līt ′fā‚shēz]
(petrology)
Rocks produced by medium- to high-grade regional metamorphism.
References in periodicals archive ?
Deep drillings revealed a zone of microcline granites and granite migmatites intruding metamorphic rocks of the granulite or amphibolite facies.
The concept of Baltic-Belarus arc-shaped granulite belts (Gorbatschev & Bogdanova 1993) recently raised doubts again, because in Central Latvia, the Inchukalns N-S trending amphibolite facies belt replaces the granulites of North Latvia, and in East Latvia, the large Daugavpils gneissose granite massif forms the basement (Puura 1980).
In western Estonia, metabasites of the amphibolite facies dominate.
Metamorphic domes in northern and northeastern Estonia diversify the generally amphibolite facies complexes of the Tallinn and Alutaguse zones.
The intrusions in the Quoddy Formation exhibit a similar metamorphic history, but amphibolite facies assemblages do not occur everywhere and are not well developed where present.
Rocks with lower amphibolite facies assemblages were faulted and subsequently retrograded to lower greenschist facies.
The lower amphibolite facies assemblage is homblende-plagioclase-titanite-magnetite, but these rocks are most commonly extensively retrograded.
Then, a progressive metamorphism in these rocks is marked by the passing of greenschist facies mineralogy [actinolite + chlorite + quartz + plagioclase (albite) + epidote minerals [+ or -] muscovite [+ or -] calcite] to epidote-amphibolite facies mineralogy [hornblende + epidote minerals + quartz + albite [+ or -] garnet], and finally to amphibolite facies mineralogy [hornblende + garnet + plagioclase [+ or -] quartz].
8 kbar, whereas those with mineral assemblages formed under epidote-amphibolite and amphibolite facies reached values of 696[degrees]C and 14.
4) RA(PP) = Prehnite-Actinolite (Prehnite-Pumpellyite) subfacies; RA = Prehnite-Actinolite facies; GS = Greenschist facies; AMPH= Amphibolite facies (abbreviations from Miyazaki and Okumura (2002)).
Metamorphic grade in the Duquet and Fagnant belts (and in the core of the Qalluviartuuq-Payne belt) is at green-schist or lower amphibolite facies, with P and T conditions as low as about 525[degrees]C and 3 kbar (Percival and Skulski 2000; Ciesielski 2000; Madore et al.
Based on petrographic and geochemical similarities, the North Estonian amphibolite facies rocks were believed to belong to a section of Svecofennian rocks cropping out in southern Finland.