sgr ms thesis - University of Maine

pluton margins (Johnson et al., 2001, 2003, 2004; Gerbi et al., 2004; Aizawa et
al., 2006). However, wall rock shortening can only account for 25-40% of a
magma chamber’s volume, so other processes must provide additional volume
for chamber expansion (Paterson and Fowler, 1993; Johnson et al., 1999).
There has been much discussion on the topic of volume accomodation by
stoping (e.g. Clarke et al., 1998; Glazner & Bartley, 2006; Clark & Erdman, 2008;
Glazner & Bartley, 2008; Paterson et al., 2008; Yoshinobu & Barnes, 2008),
assimilation (melt and mixture) of crust (e.g. Beard & Ragland, 2005; Clarke,
2007), visco-elastic deformation of host rock (e.g. Cruden & McCaffrey, 2001;
Jellinek and DePaolo, 2003; Cruden, 2005; Dietyl & Koyi, 2008; Paterson &
Farris, 2008) and dike propagation and sill accretion (e.g. Baer, 1987; Pinel &
Jaupart, 2004; Bartley et al., 2006; Michel et al., 2008). All of these processes
allow progressive growth of a shallow intrusive complex.
The continued uplift from progressive shallow intrusion magma
emplacement is often observed as a precursor for eventual magma reservoir
overpressure and rupture, wall rock failure, and caldera collapse. The
subvolcanic system is the zone between the ruptured magma reservoir and the
collapsed volcanic edifice, and it is here that the intrusive history of the volcanic
event is stored (Johnson et al., 2002).
3.2. Subsurface Response to Volcanic Eruption
Many geologists have studied the linkage between magma chambers and
volcanism through subvolcanic wall rock deformation (Lipman, 1984; Lipman,
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