Formation of high-grade ignimbrites Part II. A pyroclastic suspension current model with implications also for low-grade ignimbrites

@article{Freundt1999FormationOH,
  title={Formation of high-grade ignimbrites Part II. A pyroclastic suspension current model with implications also for low-grade ignimbrites},
  author={Armin Freundt},
  journal={Bulletin of Volcanology},
  year={1999},
  volume={60},
  pages={545-567}
}
  • A. Freundt
  • Published 12 April 1999
  • Geology
  • Bulletin of Volcanology
Abstract Analogue experiments in part I led to the conclusion that pyroclastic flows depositing very high-grade ignimbrite move as dilute suspension currents. In the thermo–fluid–dynamical model developed, the degree of cooling of expanded turbulent pyroclastic flows dynamically evolves in response to entrainment of air and mass loss to sedimentation. Initial conditions of the currents are derived from column-collapse modeling for magmas with an initial H2O content of 1–3 wt.% erupting through… 
Transport and Emplacement of the 15.4 Ma Rhyolitic Ignimbrites from Gutai Mts., Eastern Carpathians
The 15.4 Ma rhyolitic ignimbrites are the first volcanic products from Gutâi Mts. The study of their sedimentary structures reflects the mechanisms involved in the transport and emplacement of the
Small-volume, highly mobile pyroclastic flows formed by rapid sedimentation from pyroclastic surges at Soufrière Hills Volcano, Montserrat: an important volcanic hazard
Abstract Gravitational collapses of the lava dome at Soufrière Hills Volcano on 25 June and 26 December 1997 generated pyroclastic surges that spread out over broad sectors of the landscape and laid
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Small‐scale pyroclastic density currents (PDCs) associated with the AD 472 (Pollena) eruption of Somma‐Vesuvius, Italy, were generated by both magmatic and phreatomagmatic explosive fragmentation.
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  • A. Freundt
  • Environmental Science
    Bulletin of Volcanology
  • 2002
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A two layer model for the formation of dense pyroclastic basal flows from dilute, collapsing volcanic eruption columns is presented. The collapsing dilute current is described by depth averaged,
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References

SHOWING 1-10 OF 60 REFERENCES
The formation of high-grade ignimbrites, I: Experiments on high- and low-concentration transport systems containing sticky particles
Abstract High-grade ignimbrites are thought to be deposited by pyroclastic flows at temperatures exceeding minimum welding temperature or even solidus temperature. Corresponding pyroclastic-flow
Sources of unsteady column dynamics in pyroclastic flow eruptions
During the first several minutes of an explosive volcanic eruption, the flow in the column above the vent is unsteady even if the discharge from the vent is steady. At a fixed location in the column,
Emplacement of the Taupo ignimbrite by a dilute turbulent flow
AN ignimbrite is a pumice-rich deposit that records the passage of a ground-hugging ash flow (a 'pyroclastic flow') generated by the collapse of a volcanic eruption column1. Geologists study such
Explosive volcanic eruptions — IV. The control of magma properties and conduit geometry on eruption column behaviour
Summary Plinian air-fall deposits and ignimbrites are the principal products of explosive eruptions of high viscosity magma. In this paper, the flow of gas/pyroclast dispersions and high viscosity
The dynamics and thermodynamics of large ash flows
Abstract Ash flow deposits, containing up to 1000 km3 of material, have been produced by some of the largest volcanic eruptions known. Ash flows propagate several tens of kilometres from their source
A laboratory study of ash flows
Hot ash flows propagate from volcanic vents during some explosive volcanic eruptions. As a flow entrains and heats ambient air and simultaneously deposits pyroclasts, part of the flow may become less
The 1982 eruptions of El Chichon volcano, Mexico (3): Physical properties of pyroclastic surges
Two major pyroclastic surges generated during the 4 April 1982 eruption of El Chichon devastated an area of 153 km2 with a quasi-radial distribution around the volcano. The hot surge clouds
A model for generation of ash clouds by pyroclastic flows, with application to the 1980 eruptions at Mount St. Helens, Washington
Pyroclastic flows are defined as consisting of a dense basal avalanche underlying a turbulent ash cloud. The generation of ash clouds by the basal avalanche is commonly assumed to be closely related
Large-scale rheomorphic shear deformation in Miocene peralkaline ignimbrite E, Gran Canaria
Abstractthe single ignimbrite cooling unit E (average thickness, 28 m; volume, ca. 30 km3) forms the uppermost member of the Miocene Upper Mogán Formation on Gran Canaria. It is strongly chemically
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