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

• Published in: Antarctic Science
• Main Authors: Kipf, Andrea, Mortimer, Nicholas, Werner, Reinhard, Gohl, Karsten, Van Den Bogaard, Paul, Hauff, Folkmar, Hoernle, Kaj
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2012
• Subjects: Antarc*; Antarctic Science; Antarctica; Pine Island; Pine Island Bay; West Antarctica
• Online Access: http://dx.doi.org/10.1017/s0954102012000259; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102012000259

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.