Plate Tectonics and Orogenic Belts in the South-east Pacific

Abstract

GEOLOGICAL similarities suggesting the “reappearance” of the South American Andes in the Antarctic Peninsula were first noted at the turn of the century1–3. Further work4–11 was consistent with the view that the South American Andes and Antarctic Peninsula orogens have a common history since at least the Late Palaeozoic, and are to be regarded as parts of an originally continuous and rectilinear cordillera that was subsequently bent and disrupted to form the Scotia Arc. Drift reconstructions12 show this proto-cordillera bordering the Pacific margin as an uninterrupted orogenic belt throughout the Mesozoic and Early Cainozoic. Here, I question this, on the basis of a recent analysis13 which shows that the two orogens have developed under widely different tectonic conditions, and must have had different settings with regard to plate boundaries since the Late Jurassic.