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Subsolidus segregation of quartz in metamorphic differentiation of metasedimentary rocks
Doklady Earth Sciences, 2017Thermodynamic modeling of the SiO2–TiO2–Al2O3–Fe2O3–MnO–MgO–CaO–Na2O–K2O–P2O5–H2O (STAFMMCNKPOH) system at 600°C, 5 kbar has been applied to investigate dissolution and re-precipitation of quartz. Comparing silica molality in the STAFMMCNKPOH and SiO2–H2O systems, there is seen to be no effect of mineral assemblage on quartz solubility.
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Geochronology of sedimentary and metasedimentary Precambrian rocks of the West African craton
Precambrian Research, 1982Abstract This contribution summarizes current knowledge of the geochronology of the Upper Proterozoic sedimentary rocks covering the West African craton. This was done by using direct dating methods. Correlations between the northern edge of the Tindouf basin and the northern and southern part of the Taoudeni basin, as well as the Volta basin, are ...
Norbert Clauer +3 more
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Fold growth and transposition in metasedimentary rocks of the southeastern Adirondacks: Summary
Geological Society of America Bulletin, 1980INTRODUCTION Most of the estimates of the pressure and temperature for Adirondack metamorphism fall in the range of 650 to 800 °C and 7 to 9 kbar (Whitney and McLelland, 1973; Essene and others, 1977; Boone, 1978; Valley and Bohlen, 1979; Whitney and others, 1979), suggesting an elevated geothermal gradient comparable to oceanic gradients (Mercier and
JAMES W. GRANATH, NOEL BARSTOW
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GRAPHITIZATION OF METASEDIMENTARY ROCKS IN THE WESTERN KONYA
2015The Paleozoic-Mesozoic metasedimentary rocks in the study area are metacarbonate, metachert, metapelite, metasandstone and metaconglomerate. Graphite layers are 1cm to 2m thick, extend laterally for tens of meters and are intercalated with metasedimentary rocks.
KURT, Hüseyin, EREN, Yaşar
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Late Precambrian Metasedimentary Rocks of Egan Range, Nevada
AAPG Bulletin, 1963ABSTRACT Approximately 8,450 feet of polymetamorphic Late Precambrian strata are exposed at Heusser Mountain in the central northern Egan Range, Nevada. These rocks were regionally metamorphosed to slates, argillites, phyllites, metasiltstones, and quartzites; they were later contact-metamorphosed to grades as high as the biotite-zone
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Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks
Nature Geoscience, 2013The Archaean rocks of Isua, West Greenland, contain graphite, but its origins are debated. Geochemical and microscopic analyses suggest that the graphite was formed from biologically formed carbon that was deposited at least 3.7 billion years ago.
Ohtomo, Yoko +4 more
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Whole-Rock Rb-Sr Age of Metasedimentary Rocks Below the Stillwater Complex, Montana
Geological Society of America Bulletin, 1969Eight metasedimentary rocks selected from a suite collected below the Stillwater Complex in the Beartooth Mountains, Montana, yield a whole-rock Rb-Sr age of 2730 ± 150 m.y. (λ = 1.39 × 10 −11 /yr). The samples represent rocks located 0.4 to 6 miles from the lower contact of the Complex, and the nearer samples are definitely within the contact ...
J. L. POWELL +2 more
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MICROSTRUCTURES AND COMPOSITION OF ANATECTIC MELT INCLUSIONS IN METASEDIMENTARY ROCKS
2011Melt inclusions (MI) investigation represents a widely used approach to gain information on a number of igneous processes on the Earth system. The recent finding of crystallized and glassy MI in high-grade, partially melted metapelites and metagraywackes opened up the possibility to investigate also anatectic processes with the same method. The present
Ferrero S +7 more
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Geology
Abstract Sedimentary rocks archive the history of Earth’s surface. However, alteration by diagenesis, weathering, deformation, and metamorphism makes interpretating Earth’s earliest environments challenging and ambiguous. We show that detrital zircon grains preserve an unaltered account of transport history, even in billion-year-old ...
M. Colin Marvin +4 more
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Abstract Sedimentary rocks archive the history of Earth’s surface. However, alteration by diagenesis, weathering, deformation, and metamorphism makes interpretating Earth’s earliest environments challenging and ambiguous. We show that detrital zircon grains preserve an unaltered account of transport history, even in billion-year-old ...
M. Colin Marvin +4 more
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Geochemistry and sedimentology of Grampian Group metasedimentary rocks, Upper Strathspey
Scottish Journal of Geology, 1989Synopsis The sedimentological attributes of the metasedimentary rocks of Upper Strathspey are inferred from their major and trace element geochemistry. The rocks of the Glenshirra Succession have high oxidation ratios and are of a lithic nature which suggests shallow water, probably alluvial, environments.
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