Brittle Deformation of the Beacon and Ferrar
Rocks
in the Eisenhower Range ? Deep Freeze Range
Area,
Northern Victoria Land, Antarctica
F. Storti* & F. Rossetti
Dipartimento di Scienze Geologiche, Università ́Roma Treî, Largo S. L. Murialdo 1, 00146 Roma - Italia
Received 4 June 2001; accepted in
revised form 18 January 2002
Abstract - We present new data on the brittle
faults that occur in Beacon and Ferrar rocks outcropping in the northern
Eisenhower Range and in the northern Deep Freeze Range-Exposure Hill area,
in northern Victoria Land. Faults have a predominant dextral strike-slip
sense of shear and a NW-SE strike. Reverse faults with the same strike
are common. Subordinate thrust and normal faults also occur. The structural
architecture of fault populations recognised in the visited outcrops fit
into a right-lateral strike-slip tectonic framework along NW-SE striking
master faults. The presence of NE-SW striking normal faults may relate
to Ross Sea extension predating the strike-slip tectonics. However, a younger
age of at least part of them, related to the partitioned transtension which
has affected the Ross Sea Region in Late Cenozoic times or, possibly, to
fluctuations of the glacial load, cannot be ruled out. Our data provide
further support to the results of recent work on brittle faults in Victoria
Land and the Ross Sea, emphasising the significant role of intraplate right-lateral
strike-slip tectonics on the post-Jurassic structural architecture of the
region. Understanding Cenozoic deformation is thus necessary for palinspastic
restoration of the Early Paleozoic Ross orogenic belt and for better constraining
the opening and evolution of the Ross Sea.
*Corresponding author (storti@uniroma3.it)