a1 Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), Wischhofstr. 1–3, D-24148 Kiel, Germany
a2 GNS Science, Private Bag 1930, Dunedin, New Zealand
a3 Alfred Wegener Institut für Polar- und Meeresforschung, Postfach 120161, D-27515 Bremerhaven, Germany
We present geochronological and geochemical data for eight plutonic rocks from five locations in the Pine Island Bay area of West Antarctica, collected during RV Polarstern expedition ANT-XXIII/4. Ar-Ar laser method dating yielded closure temperatures ages of c. 147–98 Ma for dioritic and granitic plutonic rocks and an age range of c. 97–95 Ma for granitoid and trachyandesitic dykes. Major and trace element compositions indicate that all rocks have an I-type subduction-related chemistry. There are no A-type granitic rocks in our dataset, and none are yet reported from the Pine Island Bay area. Our results confirm earlier models of post 100 Ma subduction on this part of the Gondwana margin.
(Received October 10 2011)
(Accepted February 09 2012)
(Online publication May 14 2012)