Journal ArticleDOI
Genesis of Archean Peridotitic Magmas and Constraints on Archean Geothermal Gradients and Tectonics
TLDR
In this article, a model of peridotitic komatiite magma was developed in which selective removal of garnet during ascent produces CaO/Al 2 O 3 > 1 and heavy rare-earth element depletion in the resultant peridoteitic or mafic extrusions.Abstract:
The experimentally determined extrusion temperature (1650° ± 20°C) for Archean peridotitic komatiite magma implies diapirism of upper mantle peridotite from a depth of at least 200 km. Models of magma genesis are developed in which selective removal of garnet during ascent produces CaO/Al 2 O 3 > 1 and heavy rare-earth element depletion in the resultant peridotitic or mafic extrusions. Magma genesis can be interpreted with a model of the Archean geotherm, lithosphere, and plate tectonics processes resembling the modern Earth, but this does not account for the distinctive preservation and character of Archean greenstone belts. A preferred model of a steeper Archean geotherm, thin lithosphere (≃50 km), and asthenosphere with approximately 5 percent melting does not allow eclogitization and subduction of basaltic oceanic crust, but it postulates scraping off of such crust against and between primitive sialic nucleii. This model may account for the distinctive characteristics of the Archean greenstone and “granite” terranes.read more
Citations
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Journal ArticleDOI
Geochemistry and Sm-Nd isotopic characteristics of the Paleoarchean Komatiites from Singhbhum Craton, Eastern India and their implications
TL;DR: In this article, Kapili komatiites near Kapili village, located in Palaeo-Mesoachean Gorumahishani-Badampahar greenstone belt of Singhbhum Craton, Eastern India preserve excellent igneous textures and exhibit co-association of Al-depleted (ADK) and Al-undepleted (AUK).
Journal ArticleDOI
Origin of the earth's ocean basins
Herbert Frey,Herbert Frey +1 more
TL;DR: The earth's original ocean basins were mare-type basins produced 4 billion years ago by the flux of asteroid-sized objects responsible for the lunar mare basins as discussed by the authors.
Journal ArticleDOI
Archaean ecology: a review of evidence for the early development of bacterial biomes, and speculations on the development of a global-scale biosphere
TL;DR: The earliest living community may have consisted of a variety of chemotrophic bacteria, including both archaea and eubacteria, that existed around hydrothermal systems, and photosynthesis began in thermophilic bacteria that originally developed infra-red thermotaxis for detecting hot vents as discussed by the authors.
Journal ArticleDOI
CO2 and the eruptibility of picrite and komatiite
TL;DR: Wright, Helz and Schwindinger and Anderson as discussed by the authors showed that the 1959 eruption of Kilauea was a mixture of new, hot, MgO-rich magma that rose through and mixed with cooler stored magma causing crystallization of abundant olivine phenocrysts.
Book Chapter
Experimental petrology of basalts and their source rocks
Peter J. Wyllie,Colin H. Donaldson,Anthony J. Irving,Susan E. Kesson,Russell B. Merrill,Dean C. Presnall,Edward M. Stolper,Thomas M. Usselman,David W. Walker +8 more
TL;DR: In this paper, the authors discuss the role of the experimental petrology of erupted basalts in the analysis of the composition and mineralogy of basaltic effluent from the Earth.
Related Papers (5)
Petrogenesis of Archaean ultrabasic and basic volcanics: Evidence from rare earth elements
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