Results 261 to 270 of about 7,690 (304)

Metamorphic rocks of the mantle

1990
In certain unusual geological environments rocks derived from the Earth’s mantle are found at the surface. They have come there in one of two ways, either by tectonic movements or by volcanic eruption. Many mantle rocks coming to the surface in either way can be recognized as metamorphic by their textures.
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Origin of Metamorphic Rocks

Nature, 1954
The Origin of Metamorphic and Metasomatic Rocks A Treatise on Recrystallization and Replacement in the Earth's Crust. By Prof. Hans Ramberg. Pp. xvii + 317. (Chicago: University of Chicago Press; London: Cambridge University Press, 1952.) 75s. net.
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Metamorphism of Quartzofeldspathic Rocks

2011
Metamorphosed quartzofeldspathic rocks are derived from graywacke sandstone and siltstone (clastic sediments; Table 2.3), and granitoid protoliths such as granite, alkali-feldspar granite, granodiorite and tonalite (Table 2.3). They constitute the largest portion of the continental crust.
Rodney Grapes, Kurt Bucher
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DENSITIES OF METAMORPHIC ROCKS

GEOPHYSICS, 1971
Although metamorphic rocks comprise a large part of the crystalline crust, relatively few data concerning metamorphic rock densities are available. In this paper, we present rock densities from seven different metamorphic terrains. Mean densities for rock types range from [Formula: see text] for biotite granite gneiss to [Formula: see text] for ...
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The Laurentian rocks and metamorphism

Transactions of the Edinburgh Geological Society, 1885
In the early days of geology, as geologists are aware, granite and the associated highly metamorphic rocks were called ‶Primary Rocks,″ as from their position they were supposed to be the oldest rocks. This misnomer, in the early days of geology, was not an unnatural one, as these early observers supposed that strata accumulated by a process very ...
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Metamorphism and metamorphic rocks [PDF]

, 2012
Jochen Bundschuh, Guillermo E. Alvarado
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A classification of metamorphic rocks

Geological Society of America Bulletin, 1917
Introduction The purpose of this paper is to present a comprehensive classification of metamorphic rocks, the attempt being made to work out a satisfactory scheme without the introduction of new terms. In this proposed classification the main principles are based on (1) origin of the rocks, (2) rock structure, and (3) composition.
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Reactions in Metamorphic Rocks

1976
Some metamorphic reactions have been mentioned as examples of principles discussed in Chapter 2. Here I want to talk about (1) attempts to recognise realistic reactions from microstructural and electron micro-probe investigations of metamorphic rocks, and (2) attempts to relate observation and experiment on metamorphic reactions and phase equilibria. I
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Charnockites as metamorphic rocks

American Journal of Science, 1969
In many areas, charnockites are intimately associated with metasediments belonging to granulite facies. Both have similar textures, common mineralogical characteristics and, in several instances, the same structural pattern. From these occurrences, it is proposed that charnockites as they now occur are themselves metamorphic.
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The pressure–temperature–time–deformation history of the Beni Mzala unit (Upper Sebtides, Rif belt, Morocco): Refining the Alpine tectono‐metamorphic evolution of the Alboran Domain of the western Mediterranean

Journal of Metamorphic Geology, 2021
Patrick Moni, Federico Rossetti, Federico Lucci   +2 more
exaly