Phase equilibria and oxygen isotopes in the evolution of metapelitic migmatites: a case study from the Pre-Alpine basement of Northern Switzerland
Article Abstract:
The metapelitic migmatites obtained from Pre-Alpine boreholes exhibit amphibolite-grade metamorphism, anatectic migmatization and retrograde hydration. The petrographic, phase-diagram and oxygen isotope results show thatthe anatectic migmatization process occurred during the upward thrust of the region due to pressure decrease, while the isotopic equilibration of all minerals happened during amphibolite-grade metamorphism. In addition, quartz crystals, which were separated form quartz-rich segregations, did not undergo hydrothermal isotopic exchange unlike other rock samples.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1992
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U-Pb monazite, xenotime and titanite geochronological constraints on the prograde to post-peak metamorphic thermal history of Paleoproterozoic migmatites from the Grand Canyon, Arizona
Article Abstract:
Insights were obtained with regards to the beginning and thermal evolution of the middle crust in the Mineral Canyon block of the Upper Granite George during the Paleoproterozoic Yavapai orogeny. Data from the U-Pb geochronologic, showed that the growth of the Metamorphic monazite on the prograde path started on 1710 Ma during thrusting, F1 folding and S1 fabric development. The breakdown of muscovite to sillimanite can be attributed to partial melting of biotite schist.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1999
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U-Pb systematics of monoazite and xenotine: case studies from the Paleoproterozoic of the Grand Canyon, Arizona
Article Abstract:
The isotopic U-Pb system was characterized as a monazite that was sensitive to a variety of processes that affects the geochronometric analysis. Back-scattered electron imaging of single-crystals of monazite indicated the presence of magmatic domains that were enclosed within the crystals. The secondary domains of the crystal fragments of monazite also exhibited magmatic zoning and xenocrystic cores that were formed by fluid-mineral interaction.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1997
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