The Matusevich
Aeromagnetic Anomaly over Oates Land, East Antarctica
F. Ferraccioli1,4, D. Damaske2,
E. Bozzo1 & F. Talarico3
1Dipartimento
Territorio e Risorse, Sez. Geofisica, Università di Genova, V.le
Benedetto XV 5, 16132 Genova – Italy
2Bundesanstalt für Geowissenschaften und Rohstoffe,
Stilleweg 2, 30655 Hannover – Germany
3Dipartimento Scienze della Terra, Università di
Siena, Via del Laterino, 8, 53100 Siena - Italy
4British Antarctic Survey, High Cross, Madingley Road,
Cambridge
Received 25 March 2003; accepted in revised form 31 October 2003
Abstract
- The “Matusevich Anomaly” is a high-amplitude and linear aeromagnetic
feature imaged over Oates Land, East Antarctica. Interpretation of this
anomaly provides new geophysical insight into the Wilson Terrane. We
compare aeromagnetic signatures, ground susceptibility data and geology
to investigate the potential sources for the Matusevich Anomaly. This
comparison indicates that mylonitic hornblende-bearing Granite Harbour
Intrusives or meta-ultramafic rocks and metabasites of the Wilson
Metamorphic Complex could cause the anomaly. The magnetic bodies
located directly beneath the Matusevich Glacier lack a prominent
gravity signature. Hence, an intermediate rather than ultramafic bulk
composition of the magnetic sources is more likely, at least for the
Exiles Nunataks segment of the Matusevich Anomaly. Modelling suggests
that magnetic intrusions, at least 8-km thick, and possibly as much as
14-km thick, are required to fit the Exiles Nunataks segment of the
Matusevich Anomaly. These magnetic intrusions may reveal buried
magmatic arc crust emplaced along the Exiles fault system. This segment
of buried arc crust is an important imprint of Ross-age subduction.
Mafic/ultramafic bodies flank the arc on both sides, as indicated by
approximately coincident gravity and aeromagnetic anomalies. If these
bodies represent remnants of oceanic crust, then the Matusevich Glacier
might conceal not only a major fault, but also a former suture zone.
*Corresponding author (ffe@bas.ac.uk)