Antarctic Science

Earth Sciences

Granitoids and dykes of the Pine Island Bay region, West Antarctica

Andrea Kipfa1, Nicholas Mortimera2, Reinhard Wernera1 c1, Karsten Gohla3, Paul Van Den Bogaarda1, Folkmar Hauffa1 and Kaj Hoernlea1

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

Abstract

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)

Correspondence:

c1 Corresponding author: rwerner@geomar.de

Metrics