HR: 0800h
AN: T11A-1234    [Abstracts]
TI: High Resolution Magnetic Anomaly Imaging of Southern McMurdo Sound (Antarctica)
AU: * Chiappini, M
EM: chiappini@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia, Vigna Murata 605, Roma, 00143 Italy
AU: Gaya Pique, L R
EM: pique@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia, Vigna Murata 605, Roma, 00143 Italy
AU: Pignatelli, A
EM: pignatelli@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia, Vigna Murata 605, Roma, 00143 Italy
AU: Wilson, T
EM: twilson@mps.ohio-state.edu
AF: Ohio State University, 125 S. Oval Mall, Columbus, OH 43210 United States
AB: During the 2003-04 austral summer season, a low-altitude, high-resolution airborne magnetic survey was conducted in the area of Southern McMurdo Sound, western Ross Sea, in the framework of the joint Italian-US initiative called GEOIMAG (GEOphysical IMAGing of Antarctic tectonic and volcanic units in the Transantarctic Mountains and Ross Sea area). The survey was flown by helicopter from McMurdo Station, at a constant terrain clearance of 70 m. Profile spacing was 350 m. The resolution of the survey, the accuracy of the data acquisition, and a preliminary digital enhancement of the processed magnetic data have contributed to highlight the short-wavelength component of the regional magnetic anomaly field, resolving volcanic bodies and faults. A broad positive anomaly tapers northward from the volcanic Brown Peninsula. The breadth and low amplitude of the anomaly suggests this may mark relatively thin deposits of volcanic material on or near the seafloor. High-frequency and high-amplitude anomalies are associated with the volcanic Daily Islands at the edge of the Ross Ice Shelf. Anomalies of similar amplitude and size in adjacent areas indicate additional volcanic cones occur on the seafloor and beneath the ice sheet. Low-amplitude, curvilinear anomalies with a convex shape toward McMurdo Sound occur offshore of the outlet of Ferrar Glacier and extending southward parallel to the coastline. The new data are being integrated with a multi-source database (magnetic, digital terrain data, bathymetry, regional structural trends) to obtain an unprecedented view of the magnetic signature of the major tectonic elements in the area. The structural and volcanic framework resulting from this investigation will provide important site survey information for the proposed ANDRILL drill sites in southern McMurdo Sound.
DE: 8015 Local crustal structure
DE: 1517 Magnetic anomaly modeling
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting