BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Bubbles and Bangs: Volatile Controls on Magma Fragmentation - Kath
 y Cashman\, University of Oregon
DTSTART:20120131T163000Z
DTEND:20120131T173000Z
UID:TALK33166@talks.cam.ac.uk
CONTACT:John Maclennan
DESCRIPTION:An ongoing challenge in volcanology is to relate conditions of
  magma ascent to eruption style using information preserved in pyroclastic
  deposits. Verhoogen [1951] first suggested a correlation between the kine
 tics of bubble formation and the proportion of magma that is fragmented to
  ash\; Walker [1973\, 1981] extended this concept by linking ash formation
  (fragmentation efficiency) to eruptive style. However\, a theoretical bas
 is for this relationship is not well established. Dynamic fragmentation mo
 dels typically predict only a threshold criterion for fragmentation and no
 t the resulting grain size distribution. In contrast\, experiments that co
 nstrain relationships between grain size characteristics and fragmentation
  overpressure consider initial vesicularity but not the dynamics of decomp
 ression-related vesiculation. I will examine ways by which we can relate t
 he physical characteristics of individual clasts to the total grain size d
 istributions from which those individual clasts are derived to extend frag
 mentation models.
LOCATION:Harker 1 seminar room\, Department of Earth Sciences
END:VEVENT
END:VCALENDAR