HR: 0800h
AN: T11A-0348    [Abstracts]
TI: Effect of Magma Degassing on Dike Propagation at Mid-Ocean Ridges
AU: * Ramondenc, P
EM: pierre.ramondenc@ce.gatech.edu
AF: Georgia Institute of Technology, School of Civil and Environmental Engineering, 790 Atlantic Drive, Atlanta, GA 30332-0355, United States
AU: Germanovich, L N
EM: leonid.germanovich@ce.gatech.edu
AF: Georgia Institute of Technology, School of Civil and Environmental Engineering, 790 Atlantic Drive, Atlanta, GA 30332-0355, United States
AU: Lowell, R P
EM: rlowell@vt.edu
AF: Virginia Polytechnic Institute & State University, Department of Geosciences, 4044 Derring Hall, Blacksburg, VA 24061-0420, United States
AB: Dike propagation from a subaxial magma body at a mid-ocean ridge may initiate either near the tips or at the center of the magma body. Previous research showed that for magma bodies in the shallow crust, tip dikes could propagate to the seafloor, whereas central dikes, or dikes propagating from deep seated magma lenses may not. Previous work neglected the effect of volatile exsolution on dike propagation, however. Volatile exsolution increases magma compressibility and hence the exsolution of volatiles either prior to or during dike propagation may increase the driving force for dike propagation and increase the propagation distance. Expressing the magma compressibility as a function of the volume fraction of gas, we investigated this scenario through a range of parameters related to the magma lens characteristics. Our results show that tip dikes emerging from magma bodies at the base of the crust may reach the upper crustal magma lens provided the volatile content is greater than 3.5%. Central dikes emerging from the shallow magma chamber can reach the seafloor if the volatile content is 1.75% and the average crystal content of the lens is approximately 40-50%.
DE: 0545 Modeling (4255)
DE: 8145 Physics of magma and magma bodies
DE: 8416 Mid-oceanic ridge processes (1032, 3614)
DE: 8424 Hydrothermal systems (0450, 1034, 3017, 3616, 4832, 8135)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting