HR: 16:50h
AN: P34A-03 INVITED     [Abstracts]
TI: Icelandic Rootless Volcanic Cone Eruptions as Analogs to Explosive Lava-Water Interactions on Mars
AU: * Fagents, S A
EM: fagents@hawaii.edu
AF: HIGP/SOEST, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822, United States
AU: Bruno, B C
EM: barb@hawaii.edu
AF: HIGP/SOEST, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822, United States
AU: Hamilton, C W
EM: cwh@higp.hawaii.edu
AF: HIGP/SOEST, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822, United States
AU: Thordarson, T
EM: Thor.Thordarson@ed.ac.uk
AF: University of Edinburgh, Grant Institute, West Mains Road, Edinburgh, EH9 3JW, United Kingdom
AB: Rootless volcanic cones form by explosive lava-water interaction when a lava flow moves over a water-bearing substrate, such as lake deposits, riverbeds, or marshes. Rootless cones are common in the Holocene lava flows of Iceland, where they form groupings of hundreds of structures within a host lava flow. Since the late 1990's, high-resolution Mars Orbiter Camera and Thermal Emission Imaging System images have revealed in great detail fields of cones in the northern volcanic plains of Mars. In this case, it has been postulated that the cones are produced by interactions of lava with ice contained at shallow depths within the martian regolith. In the Cerberus region, the co-location of extensive young effusive volcanism with repeated aqueous flood events would provide a mechanism for rootless eruptions. Hundreds of cones have been identified in this area, implying the presence of low-latitude water/ice stores in geologically recent times. Our work involves detailed field studies of Icelandic rootless cones aimed at elucidating the formation mechanism of rootless explosions and developing models of the lava-water interaction. Furthermore, we have devised statistical methods for the unequivocal identification rootless cone fields on Mars, and mapped their occurrence on a number of young lava flows. Our presentation will include new insights into cone formation processes gleaned from our field campaigns, and discuss the implications for regolith ice stores on Mars.
DE: 5480 Volcanism (6063, 8148, 8450)
DE: 6225 Mars
DE: 8414 Eruption mechanisms and flow emplacement
DE: 8450 Planetary volcanism (5480, 6063, 8148)
DE: 8486 Field relationships (1090, 3690)
SC: Planetary Sciences [P]
MN: 2007 Joint Assembly