Results 61 to 70 of about 103 (92)
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Petrogenesis of Late Triassic ultramafic rocks from the Andong Ultramafic Complex, South Korea
Lithos, 2016Abstract To constrain the source and tectonomagmatic processes that gave rise to the Andong Ultramafic Complex (AUC) in South Korea, we determined the clinopyroxene Sr–Nd–Hf–Pb isotope and trace element compositions as well as the whole-rock and mineral compositions for the Late Triassic (ca. 222 Ma) ultramafic rocks from the complex.
Nak Kyu Kim, Sung Hi Choi
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Chromite spinels from ultramafic xenoliths
Geochimica et Cosmochimica Acta, 1975Abstract The spinels in ultramafic xenoliths from kimberlites and alkali olivine basalts show a wide range of compositional variation, far in excess of the ranges shown by their coexisting silicate phases. The chemical variation of the spinels is a function of the host magma, texture and depth of origin. The spinels occur in five textural types: 1.
Asish R Basu, Ian D MacGregor
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1972
The ultramafic rocks are composed mainly of dark-colored mafic or ferro-magnesian minerals such as olivine, pyroxene, amphibole, serpentine, garnet, biotite, and opaque oxides. They are usually, but not always, ultra-basic (having less than 45 percent SiO2).
Gunter Faure, James L. Powell
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The ultramafic rocks are composed mainly of dark-colored mafic or ferro-magnesian minerals such as olivine, pyroxene, amphibole, serpentine, garnet, biotite, and opaque oxides. They are usually, but not always, ultra-basic (having less than 45 percent SiO2).
Gunter Faure, James L. Powell
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Metamorphism of Ultramafic Rocks
1994Ultramafic rocks are magnesium silicate rocks that normally contain no felsic minerals or very little (
Kurt Bucher, Martin Frey
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Eos, Transactions American Geophysical Union, 1937
Introduction—The results of the work of several years are here presented in much condensed form. The material will be expanded at some late time into a more complete treatment of the problem. The broader factual data are set down in outline in the first section.
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Introduction—The results of the work of several years are here presented in much condensed form. The material will be expanded at some late time into a more complete treatment of the problem. The broader factual data are set down in outline in the first section.
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1992
Ultramafic rocks comprise less than 0.1% of the New Zealand land surface but their occurrence in areas of contrasting climate and glacial history has produced a wide range of plant habitats. Compared with other New Zealand soils, ultramafic soils, ranging from deeply weathered laterites to youthful skeletal regoliths, have low concentrations of most ...
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Ultramafic rocks comprise less than 0.1% of the New Zealand land surface but their occurrence in areas of contrasting climate and glacial history has produced a wide range of plant habitats. Compared with other New Zealand soils, ultramafic soils, ranging from deeply weathered laterites to youthful skeletal regoliths, have low concentrations of most ...
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Geotectonic significance of ultramafic rocks
Earth-Science Reviews, 1973Abstract Ultramafic rocks can be divided into 5 principal geotectonic groups, as follows: (1) Layered gabbro-norite-peridotite masses, commonly associated with all ages of terrane, possibly connected with accretionary plate margins. (2) Concentrically zoned Alaska-type bodies, possibly associated with consuming plate margins. (3) Ultramafic lavas and
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Plant–pollinator interactions in ultramafic and non-ultramafic environments in New Caledonia
Botany Letters, 2023Zakardjian, Marie +3 more
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Metasomatic Alteration of Ultramafic Rocks
1989Metasomatized ultramafic rocks from the 3800 Ma Isua supracrustal belt have been preferentially enriched in calcium, aluminium and silica, but show no or only little addition of potassium and rubidium. This unusual geochemical response to fluid infiltration can be explained in the light of a low buffered activity of aqueous silica during progressive ...
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