Garnet exsolution in pyroxene from clinopyroxenites in the Moldanubian zone: constraining the early pre-convergence history of ultramafic rocks in the Variscan orogen

0330543 - GFÚ 2010 RIV GB eng J - Journal Article
Faryad, S. W. - Dolejš, D. - Machek, Matěj
Garnet exsolution in pyroxene from clinopyroxenites in the Moldanubian zone: constraining the early pre-convergence history of ultramafic rocks in the Variscan orogen.
Journal of Metamorphic Geology. Roč. 27, č. 9 (2009), s. 655-671. ISSN 0263-4929. E-ISSN 1525-1314
Grant - others:GA ČR(CZ) GA205/06/0688; GA ČR(CZ) GP205/09/P135
Institutional research plan: CEZ:AV0Z30120515
Keywords : Bohemian Massif * clinopyroxenite * decompression * garnet lamellae
Subject RIV: DB - Geology ; Mineralogy
Impact factor: 4.157, year: 2009

Exsolution lamellae of garnet in clinopyroxene and orthopyroxene porphyroclasts from garnet pyroxenites in the Moldanubian zone were studied to elucidate the pressure-temperature conditions of the exsolution process and to reconstruct the burial and exhumation path of ultramafic rocks in the Variscan orogen. The porphyroclasts occur in a fine-grained matrix with metamorphic fabrics, which consists of clinopyroxene and small amounts of garnet, orthopyroxene and amphibole. The clinopyroxene porphyroclasts contain garnet + orthopyroxene lamellae as well as ilmenite rods that have orientation parallel to planes of the porphyroclasts. Orthopyroxene porphyroclasts host garnet and clinopyroxene lamellae, which show the same lattice preferred orientation. In both cases, lamellar orthopyroxene, clinopyroxene and garnet were partially replaced by secondary amphibole.
Permanent Link: http://hdl.handle.net/11104/0176312