Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Forward modeling of metamorphic textures
Autore:
Foster, CT;
Indirizzi:
Univ Iowa, Dept Geol, Iowa City, IA 52242 USA Univ Iowa Iowa City IA USA 52242 Iowa, Dept Geol, Iowa City, IA 52242 USA
Titolo Testata:
CANADIAN MINERALOGIST
, volume: 37, anno: 1999,
parte:, 2
pagine: 415 - 429
SICI:
0008-4476(199904)37:<415:FMOMT>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
X-RAY TOMOGRAPHY; PORPHYROBLAST CRYSTALLIZATION; THERMODYNAMIC MODELS; SILLIMANITE ZONE; MECHANISMS; GROWTH; STAUROLITE; DIFFUSION; KINETICS; RANGELEY;
Keywords:
metamorphic textures; reaction mechanisms; P-T-t path; irreversible thermodynamics; differential thermodynamics;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: Foster, CT Univ Iowa, Dept Geol, Iowa City, IA 52242 USA Univ Iowa Iowa City IA USA 52242 Geol, Iowa City, IA 52242 USA
Citazione:
C.T. Foster, "Forward modeling of metamorphic textures", CAN MINERAL, 37, 1999, pp. 415-429

Abstract

A technique of quantitative forward modeling that combines differential and irreversible thermodynamic relations is used to gain insight into the types of textures that develop in regional metamorphic terranes. Two differentP-T paths are examined that produce sillimanite-garnet schist from staurolite-garnet schist of the same bulk composition. One is an isobaric heating path from 600 degrees C to 630 degrees C at 4 kbar, and the other is an isothermal decompression path from 8 kbar to 4 kbar at 630 degrees C. The final temperature, pressure, mineral compositions, and whole-rock mineral modesare the same in the two cases. However, the mineral textures are different, allowing the two paths to be distinguished. The critical information thatpermits the paths to be discriminated is the recognition of textures that show that the higher-pressure rack originally had more garnet and less staurolite than the lower-pressure rock. There also is a difference in the reactions that produced sillimanite: in the isobaric heating case, most sillimanite is produced by staurolite breakdown, whereas in the isothermal decompression case, most sillimanite is produced by garner breakdown. The different mechanisms of sillimanite formation cause the rock that decompressed to have much less biotite in the matrix than the rock that was heated. The textures produced for each path are distinct, easily recognizable, and should persist over a wide range temperature and pressure, making it possible to identify them even if the rock undergoes multiple prograde or retrograde events. The simulations show that considerable information about the P-T history of metamorphism is recorded in textures produced by mechanisms of reaction in metapelites. Integration of this technique with regional studies of metamorphic textures has the potential to provide significant constraints on the detailed 3-D thermal history of mountain belts and valuable insight into the tectonic processes that produce them.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/07/20 alle ore 21:56:50