K-Ar geochronology of the South Shetland Islands, Lesser Antarctica: apparent lateral migration of Jurassic to Quaternary island arc volcanism
Approximately 70 K-Ar whole-rock ages for low-K tholeiitic and andesitic volcanic and intrusive rocks from the South Shetland Islands, Antarctica, including about 50 not previously published, are reviewed. Activity mainly spanned the range 130 to 30 Ma (Jurassic/Cretaceous to Oligocene/Miocene) with a very recent (∼ 2 Ma), more alkaline, renewal. Throughout the main period of activity magmatism (or, perhaps, its cessation) migrated continuously northeastwards along the length of the island chain.