IAVCEI 2013 SYMPOSIUM 3.6 REMINDER: The complexity and diversity of fallout deposits
From: Ray Cas <ray.cas@xxxxxxxxxx>
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IAVCEI 2013 SYMPOSIUM 3.6 ABSTRACT DEADLINE REMINDER:
3-6. The complexity and diversity of fallout deposits
Dear Colleagues,
This is to remind you that the deadline for submission of Abstracts for the IAVCEI 2013 Scientific Assembly in Kagoshima, Japan, from 20th to 24th July, 2013, is 31st January at http://www.iavcei2013.com. We invite submission of abstracts for Symposium 3.6: The complexity and diversity of fallout deposits. The scope of the symposium is as follows:
Pyroclastic fallout deposits have commonly been classified into end-member types, based on dispersal patterns, and deposit grain-size characteristics (e.g. Walker 1973; Pyle 1989). These deposit types have then been related to relatively simple end-member explosive eruption styles, including aspects such as plume height, explosive (fragmentation) intensity, external water – magma explosive interaction. More recently attempts have been made to relate juvenile pyroclast vesicularity to the standard eruption styles (Mueller et al. 2011). Although the dispersal – grain-size characteristic approaches are valuable for young fallout deposits whose original extent is still well preserved, there are many limitations in applying these approaches to older, variably eroded deposits. For these, the facies aspect or deposit characteristics at remaining, isolated outcrops are commonly used to infer the general eruption style. However, many recent explosive eruptions have demonstrated that explosive fallout forming eruptions can be very complex, pulsing from one eruption style to another or having characteristics of more than one style simultaneously (e.g. Etna, with simultaneous Hawaiian and micro-plinian styles). Can these multiple, simultaneous eruption styles be detected in the characteristics of the deposits, and can the deposits be distinguished from those of simple end-member eruption styles? Some explosive fallout deposit forming eruptions also experience multiple intra-plinian column collapse events that produce pyroclastic flow deposits, apparently at the same time as fallout deposits continue to form (e.g. Pinatubo, Philippines; Fogo A, Azores). Are there distinctive differences between the fallout deposits before and after the collapses, should they be treated as discrete separate fallout events and deposits, or do they just represent an ongoing continuum of the one fallout-forming event?
There are many complications in the eruptions that produce fallout deposits and these are not adequately represented in the current approach to classification. The aim of this symposium therefore is to invite presentations on the characteristics of fallout deposit forming explosive eruptions, the complexities that can occur in the eruption styles, how we recognize these complexities in the deposits, new approaches that can be used to study fallout deposits as a basis for classifying them and understanding the eruption styles, and the limitations of traditional approaches. In particular, we invite proposals on approaches that can be applied to incompletely preserved deposits, to improve understanding of their origins. We also invite multidisciplinary approaches, coupling tephra studies with numerical models and geophysical observation of the eruption dynamics.
Co-Convenors: Ray Cas* (ray.cas@xxxxxxxxxx), Kathy Cashman, Guido Giordano, Kazutaka Mannen, Laura Pioli
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Emeritus Professor Ray Cas,
School of Geosciences,
P.O. Box 28,
Monash University,
Victoria 3800, Australia.
Tel Local: (03) 9905 4897
Tel International: +61 3 9905 4897
email: ray.cas@xxxxxxxxxx
Fax: +61 3 9905 4903
http://www.geosci.monash.edu.au//about/directory/cas/index.html
President,
International Association for Volcanology and Chemistry of the Earth's Interior (IAVCEI)
http://www.iavcei.org/
Emeritus Professor Ray Cas,
School of Geosciences,
P.O. Box 28,
Monash University,
Victoria 3800, Australia.
Tel Local: (03) 9905 4897
Tel International: +61 3 9905 4897
email: ray.cas@xxxxxxxxxx
Fax: +61 3 9905 4903
http://www.geosci.monash.edu.au//about/directory/cas/index.html
President,
International Association for Volcanology and Chemistry of the Earth's Interior (IAVCEI)
http://www.iavcei.org/
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