Results 171 to 180 of about 3,013 (217)

Metasomatic mineral titanate complexing in the upper mantle

Nature, 1986
The extent and expression of metasomatism in the upper mantle are contentious issues1,2, although the process has gained widespread acceptance to account for the subsequent enrichment of previously depleted lithosphere3,4. Uncertainties exist in the origin and precise compositions of the fluids involved, as well as in the total inventory of introduced ...
Stephen E. Haggerty, A. J. Erlank, Ian E. Grey   +2 more
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Sulfide metasomatism and the mobility of gold in the lithospheric mantle

Chemical Geology, 2015
Abstract Gold is a strongly chalcophile element and its concentration and behaviour in the mantle are intimately connected to the nature, abundance and mobility of sulfide phases. In this study Au has been analysed together with a suite of chalcophile and siderophile elements in sulfides hosted in 31 mantle-derived xenoliths from Spitsbergen in the ...
J. Edward Saunders, N.J. Pearson, Suzanne Y. O'Reilly, W.L. Griffin   +3 more
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Oxidation of the Kaapvaal lithospheric mantle driven by metasomatism

Contributions to Mineralogy and Petrology, 2008
The oxidation state, reflected in the oxygen fugacity (fO2), of the subcratonic lithospheric mantle is laterally and vertically heterogeneous. In the garnet stability field, the Kaapvaal lithospheric mantle becomes progressively more reducing with increasing depth from Δlog fO2 FMQ-2 at 110 km to FMQ-4 at 210 km. Oxidation accompanying metasomatism has
Steven Creighton, Thomas Stachel, Sergei Matveev, Heidi Höfer, Catherine McCammon, Robert W. Luth   +5 more
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HENRYMEYERITE IN THE METASOMATIZED UPPER MANTLE OF EASTERN ANTARCTICA

The Canadian Mineralogist, 2007
A mineralogical study of lherzolitic and harzburgitic xenoliths of eastern Antarctica shows that the upper mantle of this region has been affected by very strong carbonate metasomatism. We describe for the first time henrymeyerite (Ba 0.97 Ca 0.03 K 0.03 Na 0.11 ) ∑1.14 (Fe 0.92 Mg 0.17 Al 0.02 ) ∑1.11 (Ti 6.66 Si 0.25 ) ∑6.91 O 16 in mantle ...
Kogarko, Lia N., Kurat, Gero, Ntaflos, Theodoros   +2 more
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Fluid Transport and Metasomatic Storage in the Mantle

1987
Alkaline intra-plate magmatism ranges from felsic to ultramafic, with the latter melts showing extremely low SiO2 activity, carbonatite being associated throughout, and all having mantle signatures. In all its forms this magmatism shows evidence of enhanced volatile activity, ranging from the chemistry of the melts through to the style of eruption ...
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Stable Zirconium Isotopic Compositions of the Metasomatized Mantle

Journal of Geophysical Research: Solid Earth
AbstractMantle metasomatism, which affects the geochemical and lithological properties of the Earth, is crucial to the evolution and modification of the Earth's interior. Variations in chemical proxy of metasomatism, including high‐field strength elements (HFSE, e.g., Zr‐Ti isotopes and isovalent Zr‐Hf), have been commonly utilized as a tool to unravel
Zongqi Zou, Yi‐Gang Xu, Zaicong Wang, Chuyu Hu, Lanping Feng, Jing‐Liang Guo, Wen Zhang, Liang Ma, Zhaochu Hu, Yongsheng Liu   +9 more
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MANTLE METASOMATISM

Annual Review of Earth and Planetary Sciences, 1985
Michael F. Roden, V. Rama Murthy
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Contrasting Types of Upper-Mantle Metasomatism?

1984
Abstract Metasomatism is now well-recognized in upper-mantle peridotite xenoliths in kimberlites and basalts. It is patent when petrographically recognizable by development of hydrous phases rich in incompatible elements, usually by replacement of anhydrous phases and sometimes associated with injection of fluids into channel ways.
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Carbon speciation and mantle metasomatism

Geochimica et Cosmochimica Acta, 2006
S. Creighton, T. Stachel, R.W. Luth
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Carbonatite metasomatism in the mantle : sources and roles of carbonate in metasomatic enrichment processes in the lithosphere

1993
Recent high pressure experimental work in the Hawaiian pyrolite+H20+C02 system (Wallace and Green, 1988; Falloon and Green, 1990) has revealed the presence of a stability field for high Mg/(Mg+LFe), sodic dolomitic carbonatite melt in equilibrium with pargasitic lherzolite at pressures greater than the decarbonation reaction opx + dol = ol + cpx + C02.
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