GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 165-11
Presentation Time: 11:00 AM


HODGIN, Eben Blake, Harvard University, 20 Oxford St, Cambridge, MA 02138, MACDONALD, Francis A., Department of Earth Science, UCSB, 2111 Webb Hall, Santa Barbara, CA 93109, CROWLEY, James, Department of Geosciences, Boise State University, Boise, ID 83725, NEWMANN, Justin, Dept. of Earth Science, UC Santa Barbara, Santa Barbara, CA 93106-9630 and CARLOTTO, Victor, Universidad Nacional de San Antonio Abad del Cusco, Avenida de la Cultura, 733, Cusco, 921, Peru

Ian Dalziel pioneered work on the Proterozoic configuration of Laurentia, Amazonia, and Kalahari, forming the core of the supercontinent Rodinia. Here we build off this work with new stratigraphic and geochronological constraints from the Arequipa terrane in southern Peru as a missing link to provide new ties between these cratons. Two Cryogenian diamictite and cap carbonate pairs, the Ediacaran Shuram Isotope Excursion, the Precambrian-Cambrian boundary, and an Early Cambrian fossil assemblage are identified in coastal southern Peru, and are used to provide an age model for basin formation. Basement ages, lithostratigraphy, and the timing of basin formation suggest a Kalahari origin of the Arequipa terrane and a connection with the Pampean Orogeny in northwestern Argentina. We propose that the Arequipa terrane rifted from the Kalahari during the Tonian to Cryogenian, was an isolated carbonate platform during the Ediacaran, and was dextrally translated along the Gondwanan margin during the Cambrian. Evidence for final amalgamation of the Arequipa terrane is recorded by Late Cambrian magmatic and metamorphic ages in the Eastern Cordillera of southern Peru.