ISSN:
1432-0819
Keywords:
Key words Carbonatite
;
Dykes
;
Diatremes
;
Gross Brukkaros
;
Phreatomagmatism
;
Namibia
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
Notes:
Abstract In the Upper Cretaceous Gross Brukkaros Volcanic Field, southern Namibia, a radial dyke system surrounds a dome structure and its 74 closely related carbonatite diatremes. This paper focuses on volcanological features which seem to be typical for a low-viscosity melt in various settings such as dykes, sills and diatremes. The total or near absence of vesicles in carbonatite ash grains and lapilli inside the diatremes is evidence against explosive exsolution of volatile phases and in favour of a phreatomagmatic fragmentation mechanism and thus for a phreatomagmatic eruption mechanism of the carbonatite diatremes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004450050150
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