A fission track thermochronological study of King George and Livingston islands, South Shetland Islands (West Antarctica)

• Published in: Antarctic Science
• Main Authors: SELL, I., POUPEAU, G., GONZÁLEZ-CASADO, J.M., LÓPEZ-MARTÍNEZ, J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2004
• Subjects: Antarc*; Antarctic; Antarctic Peninsula; Antarctic Science; Antarctica; King George Island; Livingston Island; South Shetland Islands; West Antarctica
• Online Access: http://dx.doi.org/10.1017/s0954102004001907; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102004001907

This paper reports the dating of apatite fission tracks in eleven rock samples from the South Shetland Archipelago, an island arc located to the north-west of the Antarctic Peninsula. Apatites from Livingston Island were dated as belonging to the Oligocene (25.8 Ma: metasediments, Miers Bluff Formation, Hurd Peninsula) through to the Miocene (18.8 Ma: tonalites, Barnard Point). Those from King George Island were slightly older, belonging to the Early Oligocene (32.5 Ma: granodiorites, Barton Peninsula). Towards the back-arc basin (Bransfield Basin), the apatite appears to be younger. This allows an opening rate of approximately 1.1 km Ma −1 (during the Miocene–Oligocene interval) to be calculated for Bransfield Basin. Optimization of the apatite data suggests cooling to 100 ± 10°C was coeval with the end of the main magmatic event in the South Shetland Arc (Oligocene), and indicates slightly different tectonic-exhumation histories for the different tectonic blocks.