Evidence for pre-Jurassic subduction in western Antarctica
The South Shetland Islands (from King George Island to Livingston Island) are situated on a small crustal plate bounded by incipient back-arc spreading along the axis of Bransfield Strait to the east, a well defined oceanic trench to the west (along which subduction has apparently now ceased) and transverse faulting to the north and south1 (Fig. 1), The discovery of glaucophane-schists on Smith Island (Fig. 1, inset) suggests that subduction may have begun as early as the Upper Palaeozoic.