Results 161 to 170 of about 5,323 (197)
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Mineralogical Magazine, 1981
AbstractNormal carbonatite magmas are characteristically associated with ijolites and produce extensive fenitization by alkali metasomatism, commonly feldspathization or phlogopitization. The sequence of carbonatites developed from this magma are characterized by igneous isotopic ratios, high contents of incompatible elements, their distinctive pattern
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AbstractNormal carbonatite magmas are characteristically associated with ijolites and produce extensive fenitization by alkali metasomatism, commonly feldspathization or phlogopitization. The sequence of carbonatites developed from this magma are characterized by igneous isotopic ratios, high contents of incompatible elements, their distinctive pattern
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Nature, 1957
IN 1952 1 one of us described specimens of syenitic and carbonate rocks collected in northern Kivu, near the south-western termination of the Lake Edward Rift, by Borgniez, in 1938 2. The junior author has recently had the opportunity of revisiting the locality and has established the carbonatitic nature of the carbonate rocks.
P. DE BÉTHUNE, A. MEYER
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IN 1952 1 one of us described specimens of syenitic and carbonate rocks collected in northern Kivu, near the south-western termination of the Lake Edward Rift, by Borgniez, in 1938 2. The junior author has recently had the opportunity of revisiting the locality and has established the carbonatitic nature of the carbonate rocks.
P. DE BÉTHUNE, A. MEYER
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Properties of Carbonatite Magma and Processes in Carbonatite Magma Chambers
The Journal of Geology, 1983The physical and thermal properties of carbonatite magmas are estimated by analogy with alkali carbonate melts, which are ionic liquids, composed of discrete, unpolymerized ions. Carbonatite magmas are estimated to have low viscosity (on the order of 5 × 10-2 poise), low heat of fusion (175 J/gm), and large thermal diffusivity (4 × 10-3 J/cm-sec-K ...
Allan H. Treiman, Andrew Schedl
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Mineralogical Magazine, 2000
The tenth Carbonatite Workshop was held at University College London on 19th February 1999. This workshop was unusual in being partly thematic, with a special presentation of research on the newly discovered Italian carbonatites. The following eight papers are representative of the material presented, with the similar bias towards the important Italian
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The tenth Carbonatite Workshop was held at University College London on 19th February 1999. This workshop was unusual in being partly thematic, with a special presentation of research on the newly discovered Italian carbonatites. The following eight papers are representative of the material presented, with the similar bias towards the important Italian
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Carbonatite differentiation processes
International Geology Review, 1982(1982). Carbonatite differentiation processes. International Geology Review: Vol. 24, No. 9, pp. 1079-1089.
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Bayan Obo Carbonatites: Texture Evidence from Polyphase Intrusive and Extrusive Carbonatites
Acta Geologica Sinica - English Edition, 2010Abstract:Most of the so‐called Bayan Obo fine‐grained dolomite marbles collected from the main and east orebodies show a microporphyritic texture, namely the microphenocrysts are set in a very finegrained matrix, although nearly all of them have undergone recrystallization caused either by deformation or alteration.
WANG Kaiyi +4 more
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Geological Society of America Bulletin, 1956
The carbonatites are essentially carbonate-silicate rock with a great variety of other minerals. In this review the writer stresses the field and geochemical relationships of the carbonatites and alkalic igneous rocks and concludes that carbonatites were deposited by carbonatic solutions having a wide range of temperature, pressure, and concentration ...
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The carbonatites are essentially carbonate-silicate rock with a great variety of other minerals. In this review the writer stresses the field and geochemical relationships of the carbonatites and alkalic igneous rocks and concludes that carbonatites were deposited by carbonatic solutions having a wide range of temperature, pressure, and concentration ...
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Geological Society, London, Special Publications, 1987
Summary Carbonatites found in strongly alkaline intra-plate petrographic volcanic provinces are associated with olivine-poor nephelinites and with phonolites. Olivine-rich nephelinites occur in basanitic and alkali basalt provinces, normally without carbonatites.
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Summary Carbonatites found in strongly alkaline intra-plate petrographic volcanic provinces are associated with olivine-poor nephelinites and with phonolites. Olivine-rich nephelinites occur in basanitic and alkali basalt provinces, normally without carbonatites.
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Geological Curator, 2014
Geological material is the most chemically diverse of all types of natural history collections. Each mineral assemblage will require a specific set of environmental parameters to ensure stability. Unfortunately these are not yet fully understood and it is widely recognised that there is no environmental condition which will be suitable for all.
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Geological material is the most chemically diverse of all types of natural history collections. Each mineral assemblage will require a specific set of environmental parameters to ensure stability. Unfortunately these are not yet fully understood and it is widely recognised that there is no environmental condition which will be suitable for all.
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