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Yardangs in terrestrial ignimbrites: Synergistic remote and field observations on Earth with applications to Mars [PDF]
Planetary and Space Science, 2010 The conditions of formation and the form of yardangs in ignimbrites in the Central Andes of Chile, Bolivia, and Argentina may be the most convincing terrestrial analog to the processes and lithology that produce the extensive yardangs of the Medusae ...
Shanaka L de Silva, Kathleen E Mandt
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Elutriation pipes in ignimbrites: An analysis of concepts based on the Huichapan Ignimbrite, Mexico
Journal of Volcanology and Geothermal Research, 2020Abstract The upper portion of the Huichapan Ignimbrite (UHI), central Mexico, is a non-welded massive ignimbrite characterized by large and well-developed fines-poor elutriation pipes. We conclude that the most important pipe-forming process in the Huichapan Ignimbrite was deposition-triggered aggregative-type segregation, and this process is ...
Jaime G. Pacheco-Hoyos +2 more
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Ignimbrite types and ignimbrite problems
Journal of Volcanology and Geothermal Research, 1983Abstract A spectrum of ignimbrite emplacement types exists, ranging from the “conventional” high-aspect ratio (H.A.R.I.) type, emplaced relatively quietly and passively in valleys, to the low-aspect ratio (L.A.R.I.) type, emplaced cataclysmically. Features of the L.A.R.I., such as a remarkable ability to scale mountains and cross open water and a ...
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Landscapes Developed on Ignimbrites
2017This paper analyses the landforms and landscapes developed on ignimbrites outcropping in different regions of Argentina: Portezuelo (province of Mendoza), Lihuel Calel (province of La Pampa), Pilcaniyeu (province of Rio Negro), Barda Colorada (province of Chubut) and Chon Aike (province of Santa Cruz). Some of these localities show clear resemblance to
Aguilera, Emilia Yolanda +2 more
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Ignimbrites and ignimbrite-forming eruptions
1988Ignimbrites are the most voluminous of volcanic products. Some are the largest single eruptive units known, covering thousands of square kilometres and having volumes of more than 1000 km3. Although man has never witnessed an eruption giving rise to such large volume units, they must be the most cataclysmic of all geological phenomena.
R. A. F. Cas, J. V. Wright
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Sheathfolds in rheomorphic ignimbrites
Bulletin of Volcanology, 2004Structural reappraisal of several classic rheomorphic ignimbrites in Colorado, Idaho, the Canary Islands and Italy has, for the first time, revealed abundant oblique folds, curvilinear folds and sheathfolds which formed during emplacement. Like their equivalents in tectonic shear-zones, the sheathfold axes lie sub-parallel to a pervasive elongation ...
Branney, MJ, Barry, TL, Godchaux, M
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Nature, 1962
F. J. FITCH1 has criticized a new hypothesis proposed by me2 on the origin of ignimbrites of Pliocene to Pleistocene Age, from the North Island of New Zealand. The new petrogenetic concept is based on the presence of two contrasting glasses and their textural relationship, which suggest liquid immiscibility.
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F. J. FITCH1 has criticized a new hypothesis proposed by me2 on the origin of ignimbrites of Pliocene to Pleistocene Age, from the North Island of New Zealand. The new petrogenetic concept is based on the presence of two contrasting glasses and their textural relationship, which suggest liquid immiscibility.
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Journal of Volcanology and Geothermal Research, 2013
Abstract Rheomorphic structures in welded ignimbrites are commonly associated with deposition from hot pyroclastic flows on inclined topography or by tractional shear on aggrading agglutinate by the pyroclastic density current. We describe a type of rheomorphic deformation involving the formation of diapirs in ignimbrite following the re ...
Raffaello Cioni, Maurizio Mulas
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Abstract Rheomorphic structures in welded ignimbrites are commonly associated with deposition from hot pyroclastic flows on inclined topography or by tractional shear on aggrading agglutinate by the pyroclastic density current. We describe a type of rheomorphic deformation involving the formation of diapirs in ignimbrite following the re ...
Raffaello Cioni, Maurizio Mulas
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Crystal concentration in ignimbrites
Contributions to Mineralogy and Petrology, 1972A comparison of the crystal contents of selected sieve grades from 9 ignimbrites, with the yield of crystals from crushed pumice, shows that on average a tenfold concentration of crystals has taken place in the ignimbrites. This is explained by the selective loss of pumice by an amount equal to at least the present bulk of the samples studied.
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The ignimbrite source problem: Significance of a co-ignimbrite lag-fall deposit
Geology, 1977A co-ignimbrite lag-fall deposit is one that forms at or near the site of eruptive column collapse and consists mainly of pyroclasts that are too large and too heavy to be carried away in the resulting pumice flows. An example from Mexico is identified as such because it shows the same compositional zoning from rhyolite to andesite as the associated ...
John V. Wright, George P. L. Walker
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