Results 151 to 160 of about 4,124 (186)

Formation of “Tuffisitic Kimberlites” by phreatomagmatic processes

Journal of Volcanology and Geothermal Research, 2008
The rock type “Tuffisitic Kimberlite” (TK) occurs in the deeper diatremes of some Southern African, Canadian and Siberian kimberlite pipes and has been considered a unique rock type related to a particular emplacement process. The key features of this rock type are its fragmental nature, its massive, well-mixed appearance and a specific matrix ...
Stephan Kurszlaukis, Volker Lorenz
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Miocene phreatomagmatic volcanism at Tihany (Pannonian Basin, Hungary)

Journal of Volcanology and Geothermal Research, 2001
Abstract A late Miocene (7.56 Ma) maar volcanic complex (Tihany Maar Volcanic Complex — TMVC) is preserved in the Pannonian Basin and is part of the Bakony–Balaton Highland Volcanic Field. Base surge and fallout deposits were formed around maars by phreatomagmatic explosions, caused by interactions between water-saturated sediments and alkali basalt ...
K Németh, U Martin, Sz Harangi
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Phreatomagmatism and its relevance

Chemical Geology, 1987
Abstract Phreatomagmatic explosive volcanism results from the interaction of magma with external water, groundwater or surface water, close to or at the Earth's surface. Magma of any composition, acid to ultrabasic, may be involved in this type of explosive activity.
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Subaqueous phreatomagmatic explosion breccias at Buttercup Hill, Noranda, Quebec

Canadian Journal of Earth Sciences, 1989
Irregular, branching, white-fragment breccia dikes are restricted to the uppermost flows of the Amulet formation, where they occur within or are parallel to synvolcanic faults. At Buttercup Hill, the breccia dikes bifurcate upward and are continuous with a localized deposit of identical, conformable breccia within the lowermost andesitic flows of the ...
H. L. Gibson, D. H. Watkinson, C. D. A. Comba   +2 more
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Phreatomagmatic explosions in subaqueous volcanism

2003
Pyroclastic deposits, produced during subaqueous volcanic eruptions, point to the existence of explosive processes. Magma/water interaction is a possible source of these explosions. Under atmospheric pressure a thermohydraulic explosion mechanism was identified that can explain the high kinetic energy release of phreatomagmatic explosion and the ...
Bernd Zimanowski, Ralf Büttner
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Large volume phreatomagmatic ignimbrites from the Colli Albani volcano (Middle Pleistocene, Italy)

Journal of Volcanology and Geothermal Research, 2002
Abstract In this paper we describe four large volume, ash- and accretionary lapilli-rich, phreatomagmatic compound ignimbrite units, mafic in composition, from Colli Albani volcano, south of Rome. The four units, that form the ‘Pisolitic Tuffs’ succession, are separated by paleosols and represent the earliest explosive large volume eruptive episodes ...
DE RITA D, GIORDANO, Guido, ESPOSITO A, FABBRI M, RODANI S.   +4 more
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Impure coolants and interaction dynamics of phreatomagmatic eruptions

Journal of Volcanology and Geothermal Research, 1996
Abstract Phreatomagmatic eruptions resulting from interaction of magma with groundwater are common in many terrestrial settings, and their explosivity is widely accepted to result from fuel-coolant interaction (FCI) processes. Relatively little attention has been given to the precise nature of the volcanic settings in which phreatomagmatic FCI's take
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Silicic phreatomagmatism in the Snake River Plain: the Deadeye Member

Bulletin of Volcanology, 2010
Non-welded rhyolitic pyroclastic units in the central Snake River Plain are interbedded with the much better exposed, large-volume ‘Snake-River type’ rheomorphic welded rhyolitic ignimbrites and rhyolite lavas. We document one such unit to investigate why it is so different from the interbedded welded ignimbrites. The newly recognised Deadeye Member of
Ellis, B, Branney, MJ
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On the first experimental phreatomagmatic explosion of a kimberlite melt

Journal of Volcanology and Geothermal Research, 1998
Abstract Detailed field investigations of kimberlite pipes of the Upper Cretaceous Gibeon Kimberlite Field in southern Namibia revealed geologic features which do neither agree with extensive nor with explosive vesiculation. In the pipe Hanaus 2, vesicle-free magmatic kimberlite intruded the diatreme as a plug. Here we report on the first experiments
S Kurszlaukis, R Büttner, B Zimanowski, V Lorenz   +3 more
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Rhyolitic phreatomagmatism explored: Tepexitl tuff ring (Eastern Mexican Volcanic Belt)

Journal of Volcanology and Geothermal Research, 2011
Abstract Rhyolitic Tepexitl tuff ring in the Serdan-Oriental Basin of the eastern Trans-Mexican Volcanic Belt is a young, well-preserved circular crater — a simple morphology that belies a more complex eruptive history. Field observations, ash studies (granulometry, componentry, and morphology) and volatile data (LOI and XRF) allow the broad division
Allison Austin-Erickson, Michael H. Ort, Gerardo Carrasco-Núñez   +2 more
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