Results 131 to 140 of about 2,061 (160)
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Mechanism of formation of diatremes
International Geology Review, 1979(1979). Mechanism of formation of diatremes. International Geology Review: Vol. 21, No. 10, pp. 1131-1139.
L. A. Novikov, R. M. Slobodskoy
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On diamantiferous diatremes [discussion]
Economic Geology, 1965Discussion by P. C. Benedict (p. 638-639), M. G. Bardet (p. 827-830), M. J. O9Hara and E. L. P. Mercy (p. 830-832), and T. C. James (p. 1073-1080), and author9s reply (p. 1735-1739). In the author9s reply, eclogites, garnet peridotites, and diamonds in kimberlite are considered to be of crustal origin.
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The Journal of Geology, 1962
opposite shore of the Firth of Forth. Then it is merely necessary to accept that the simple ring faults seen at the surface of modern calderas are continued at depth (Wilshire's fig. 6, c, p. 480, would well serve to illustrate this if allowance is made for displacement at the neck margin).
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opposite shore of the Firth of Forth. Then it is merely necessary to accept that the simple ring faults seen at the surface of modern calderas are continued at depth (Wilshire's fig. 6, c, p. 480, would well serve to illustrate this if allowance is made for displacement at the neck margin).
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THE EMPLACEMENT OF SOME DIATREME-FACIES KIMBERLITES
Physics and Chemistry of the Earth, 1975Abstract Kimberlite breccias from several South African pipes or pipe-like enlargements on dykes contain abundant fragments of country rocks including huge, often brecciated, xenolithic masses which are located at positions well below their original stratigraphic levels.
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KIMBERLITIC DIATREMES IN NORTHERN COLORADO AND SOUTHERN WYOMING
Physics and Chemistry of the Earth, 1975Abstract Thirty-six kimberlitic diatremes and dikes occur in a north-south zone in the Precambrian core of the Colorado-Wyoming Front Range. A group of nineteen of apparent Middle Paleozoic age, near the state line, has been studied in detail. These pipes of intrusive breccia contain a varied assortment of nodular material, including spinel and ...
M.E. McCallum +2 more
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Journal of Volcanology and Geothermal Research
The Zákupy diatreme is well exposed by an abandoned quarry on Kamenický Vrch Hill (Czech Republic) located in the Lusatian (Lausitz) Volcanic Field in the eastern part of the NE-SW trending Ohře Rift. The abandoned quarry's walls extend upward over 50 m exposing the lower and upper diatreme facies.
Rapprich, Vladislav +7 more
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The Zákupy diatreme is well exposed by an abandoned quarry on Kamenický Vrch Hill (Czech Republic) located in the Lusatian (Lausitz) Volcanic Field in the eastern part of the NE-SW trending Ohře Rift. The abandoned quarry's walls extend upward over 50 m exposing the lower and upper diatreme facies.
Rapprich, Vladislav +7 more
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Diamantiferous diatremes; discussion
Economic Geology, 1965M. J. O'Hara, E. L. P. Mercy
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1986
Models of the structure of kimberlite pipe systems are based upon evidence obtained by the deep mining of kimberlites in South Africa and the recognition of epiclastic kimberlites as the near-surface and subaerial expression of kimberlitic volcanism. Combination of these observations has resulted in a model of a kimberlite pipe system (Figure 3.1) in ...
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Models of the structure of kimberlite pipe systems are based upon evidence obtained by the deep mining of kimberlites in South Africa and the recognition of epiclastic kimberlites as the near-surface and subaerial expression of kimberlitic volcanism. Combination of these observations has resulted in a model of a kimberlite pipe system (Figure 3.1) in ...
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On the origin of diamantiferous diatremes
Bulletin Volcanologique, 1970Diamantiferous diatremes usually occur in the old platforms and shields where deep fractures are «blind»,i.e., these fractures do not come out to the earth surface. Alkaline-ultrabasic magma ascending along these fractures and encountering an impervious cap of sedimentary and/or volcanic rocks had formed, between the cap and the basemnet rocks ...
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Diatremes with Kimberlitic Affinities in North-Central Montana
Science, 1968Diatremes in the Missouri River Breaks demonstrate systematic subsidence-ring structure, contain inclusions derived from far above and far below, and have been produced by gas-rich eruptions of alkalic ultramafic magmas. Similar magmas have produced diatremes in many localities in the world and are known to be closely associated with and probably ...
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