HR: 1340h
AN: P13A-1043    [Abstracts]
TI: Evidence of Tectonic Fractures as Magma Conduits in the Prometheus Area on Io
AU: Leone, G
EM: leone@unix.lancs.ac.uk
AF: Lancaster University, Environmental Sciences Department, Bailrigg, Lancaster, La1 4YQ, United Kingdom
AU: * Davies, A G
EM: Ashley.Davies@jpl.nasa.gov
AF: JPL, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Wilson, L
EM: L.Wilson@lancaster.ac.uk
AF: Lancaster University, Environmental Sciences Department, Bailrigg, Lancaster, La1 4YQ, United Kingdom
AU: Williams, D A
EM: David.Williams@asu.edu
AF: Arizona State University, School of Earth and Space Exploration, Box 871404, Bateman Physical Sciences F506B, Tempe, AZ 85287, United States
AU: Keszthelyi, L P
EM: laz@usgs.gov
AF: USGS-Flagstaff, Astrogeology Branch, 2255 N. Gemini Road, Flagstaff, AZ 86001, United States
AB: As previously observed during the preliminary analysis of the first Galileo high resolution imaging [1], magma stored in a shallow reservoir exploited a vent along a tectonic fissure extending from the southern corner of the Prometheus patera [2, 3] to feed the long lava flows located in the flow field west of the Prometheus Mesa (see NASA image PIA02565 (Sources of Volcanic Plumes Near Prometheus). Recent analysis of the I24 and I27 imagery have shown that lava flows have been erupted from the westernmost of the tectonic fractures which is connected to the southern tip of the patera and to the eastern hotspot in the inset image in NASA image PIA02512 (Ongoing Geologic Activity at Prometheus Volcano, Io), thus suggesting that the fractures could be directly linked to the Prometheus plumbing system favouring a path to the surface for rising magmas. Although some flows, perhaps the most recent, come from this fracture, we cannot rule out patera overflows yet as a possible source of some of the southern flow field (as well as the northern flows coming out of the patera) due to the low resolution of the available images. Further analysis of the I24 data also shows that the south-eastern margin of the flow field does not contain vents and its morphology is suggestive of embayment in the rough topography along the main fault which heads to the southern tip of the Prometheus patera rather than originating from it as previously thought in the preliminary observations. The tectonic scenario observed in the Prometheus area, mainly thrust faults, is consistent with the horizontal stress, much greater than the (essentially lithostatic) vertical stress component throughout most of the lithosphere of Io, due to the volcanic activity which produces the high eruptive resurfacing rate and the consequent subsidence of the crust. References: [1] McEwen et al., Science 288, 1193, 2000. [2] Davies et al., Icarus 184, 460, 2006. [3] Keszthelyi et al., JGR 106, 33,025, 2001. Part of this work was carried out at the Jet Propulsion Laboratory-California Institute of Technology under contract to NASA and with the support of a grant from the NASA Planetary Geology and Geophysics Program.
DE: 5480 Volcanism (6063, 8148, 8450)
DE: 6219 Io
DE: 8425 Effusive volcanism
DE: 8450 Planetary volcanism (5480, 6063, 8148)
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting