HR: 1340h
AN: V23A-0683    [Abstracts]
TI: Magnetic Anisotropy in Ferrar Sills from the Upper Taylor Glacier Region, Southern Victoria Land, Antarctica
AU: Grunow, A M
EM: grunow.1@osu.edu
AF: Byrd Polar, Ohio State U., 1090 Carmack Rd., Columbus, OH 43210
AU: * Fleming, T H
EM: flemingt1@southernct.edu
AF: Dept. of Earth Sci., Southern Connecticut State U., 501 Crescent Street, New Haven, CT 06515
AU: Priest, J
V23A-0683 AF: Dept. of Earth Sci., Southern Connecticut State U., 501 Crescent Street, New Haven, CT 06515
AU: Calhoun, A
EM: acalhoun@mac.com
AF: Dept. of Earth Sci., Southern Connecticut State U., 501 Crescent Street, New Haven, CT 06515
AU: Marshak, S
EM: smarshak@uiuc.edu
AF: Dept. of Geology, U.. of Illinois, 1301 W. Green St, Urbana, IL 61801
AU: Whittington, A
EM: whittingtona@missouri.edu
AF: Dept. of Geol. Sci., U. Missouri, 101 Geology Building, Columbia, MO 65211
AB: Jurassic tholeiites of the Ferrar Large Igneous Province (FLIP) crop out in a linear belt that extends for over 3000 km along the Transantarctic Mountains. The FLIP was emplaced over a short time (<1 m.y.) and is temporally associated with the initiation of Gondwana break-up. The intrusive phase of the FLIP consists primarily of a high level complex of dolerite sills and subordinate dikes that have intruded near the base of and within flat-lying sedimentary strata of the Beacon Supergroup. No regionally extensive feeder system has been identified and a number of possible magma transport models have been proposed. We are currently in the process of conducting an integrated structural, geochemical, petrofabric, and magnetic study aimed at establishing flow directions in intrusions from the upper Taylor Glacier. During our pilot study, 454 magnetic drill cores were collected from within two meters of the margins of sills and a few dikes at 15 locations. Mean magnetic susceptibilities for the Ferrar samples were generally low, ranging between 0.5 to 40 SI x 10-5 units. The degree of anisotropy of magnetic susceptibility (AMS) was low, ranging between 1.002 and 1.044. In a number of locations, the AMS results define a clustering of directions such that a flow trend could be inferred, as summarized below: Basement Sill: This sill was sampled in two areas of the Pearse Valley. At each location, well-grouped AMS directions were obtained. We were able to establish a flow trend from both the top and bottom margins of the basement sill to be NW/SE. Peneplain Sill: The lower contacts of this sill were sampled in Pearse Valley and at Pandora Spire. Data from samples up to 50cm from the contact were reasonably grouped. The K1 directions tended to define a NW/SE grouping. Beacon Sills: Sills intruding the Beacon Supergroup were sampled at five locations in the Quartermain Mountains region south of Beacon Valley. The K1 trend obtained from one location is ~NW/SE.
DE: 1518 Magnetic fabrics and anisotropy
DE: 4207 Arctic and Antarctic oceanography (9310, 9315)
DE: 8121 Dynamics: convection currents, and mantle plumes
DE: 8137 Hotspots, large igneous provinces, and flood basalt volcanism
DE: 9611 Jurassic
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005