HR: 0800h
AN: T11A-1248    [Abstracts]
TI: Jun Jaegyu Volcano: A Recently Discovered Alkali Basalt Volcano in Antarctic Sound, Antarctica
AU: * Hatfield, A
EM: ahatfiel@hamilton.edu
AF: Hamilton College, Dept. of Geology, Clinton, NY 13323 United States
AU: Bailey, D
AF: Hamilton College, Dept. of Geology, Clinton, NY 13323 United States
AU: Domack, E
AF: Hamilton College, Dept. of Geology, Clinton, NY 13323 United States
AU: Brachfeld, S
AF: Montclair State University, Dept. of Earth & Environmental Sciences, Upper Montclair, NJ 07043 United States
AU: Gilbert, R
AF: Queen's University, Dept. of Geological Sciences, Kingston, ON K7C3N6 Canada
AU: Ishman, S
AF: Southern Illinois University, Dept. of Geology, Carbondale, IL 62901 United States
AU: Krahmann, G
AF: Lamont-Doherty Earth Observatory, 61 Route 9W, Palisades, NY 10964 United States
AU: Leventer, A
AF: Colgate University, Dept. of Geology, Hamilton, NY 13346 United States
AB: Jun Jaegyu is a young volcanic construct discovered in May 2004 by researchers aboard the National Science Foundation (NSF) vessel {\it Laurence M. Gould} (LMG04-04). The volcano is located on the Antarctic continental shelf in Antarctic Sound, approximately 9 km due north of the easternmost point of Andersson Island. Swath bathymetry (NBP01-07) indicates that the volcano stands 700 meters above the seafloor, yet remains 275 meters short of the ocean surface. The seamount lies along a northwest-southeast oriented fault scarp and contains at least 1.5 km$^{3}$ of volcanic rock. Video recording of the volcano's surface revealed regions nearly devoid of submarine life. These areas are associated with a thermal anomaly of up to $0.052\deg$C higher than the surrounding ocean water. A rock dredge collected ~13 kg of material, over 80% of which was fresh volcanic rock; the remainder was glacial IRD. These observations, along with reports by mariners of discolored water in this region of Antarctic Sound, suggest that the volcano has been recently active. The basalt samples are generally angular, glassy and vesicular. Preliminary petrographic observations indicate that plagioclase, olivine, and clinopyroxene are all present as phenocryst phases, and that small ($<$1cm) rounded xenoliths are common. A comprehensive study of the volcano's petrography and whole-rock chemistry is currently underway. Jun Jaegyu is the northernmost volcanic center of the James Ross Island Volcanic Group (JRIVG), and the only center in this region of the Antarctic Peninsula with evidence of recent activity. It lies along the boundary between the Late Cenozoic JRIVG and the Upper Paleozoic rocks of the Trinity Peninsula Formation. While the tectonic setting of the region is complex, volcanism appears to be associated with active faults related to within-plate extension.
DE: 9310 Antarctica
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting