9418236 Dalziel A recent hypothesis that the proto-Appalachian margin of Laurentia rifted from the proto-Andean Margin of South america at the end of the Precambrian, and that the Appalachian and Andean orogens were initially a single mountain system resulting from Paleozoic Laurentia-Gondwana interaction, has many far reaching implications. This project will test this hypothesis principally by geologic and geochronologic study of poorly known but critical basement rocks of the Andean Cordillera in northernmost Chile and a paleomagnetic study of Cambrian, Ordovician, and Silurian Strata of the northwest Argentine Precordillera. Results should increase understanding of the origin and development of the Pacific margin of South America in addition to testing the SWEAT hypothesis.
