continental breakup Jurassic 20 Gondwana 18 Patagonia 18 South America 12 large igneous province 8 paleomagnetism 8 tectonic evolution 8 Argentina 6 Paleomagnetism 6 continental margin 6 paleogeography 6 rifting 6 spreading center 6 Andes 4 Chile 4 Cretaceous 4 Gastre 4 Geomagnetism 4 Rifting 4 Southern Ocean 4 Subduction 4 Triassic 4 Weddell Sea 4 apparent polar wander path 4 argon-argon dating 4 backarc basin 4 basin evolution 4 batholith 4 collision zone 4