Abstract
- During the joint German-Italian Antarctic expedition 1999-2000, new
tectonic results triggered a revisiting of the classic terrane model
for northern Victoria Land which postulated three terranes, the
high-grade Wilson Terrane and the very low-grade to low-grade Bowers
and Robertson Bay terranes. The brittle character of the former terrane
boundaries was studied in detail and it was shown, that Meso- to
Cenozoic brittle to semi-brittle tectonics has overprinted the
inherited Early Palaeozoic structural pattern to a large extent. In
addition to a revision of the Ross-orogenetic pattern in northern
Victoria Land, the tectonic history and the arguments for a simple
three-terrane model were questioned. A new model is proposed, which
accepts the allochthonous character of arc volcanics and sediments, now
called the Bowers Arc Terrane. These Bowers Arc rocks collided due to
W-directed subduction processes with the Wilson active margin of
Gondwana. As it is not yet proven that the Wilson plutonic and
metamorphic rocks form a distinct terrane themselves, the term Wilson
Terrane is abandoned consequently in favour of the newly suggested
Wilson Mobile Belt. In addition, there are no proofs that the
metasedimentary rocks of the Robertson Bay Group metasedimentary rocks
docked as a separate terrane to the Bowers Arc Terrane. These
turbidites were deposited after docking of the Bowers Arc and represent
the continued sedimentary history in an accretionary environment at the
Gondwana active margin.
*Corresponding author (nw.roland@bgr.de)