CONSTRAINTS FROM THE AREQUIPA TERRANE ON THE NEOPROTEROZOIC-CAMBRIAN RIFT HISTORY OF LAURENTIA

As a commonly proposed missing link between eastern Laurentia and western Amazonia, the Arequipa Terrane (Central Andes, western South America) can be used to test the configuration of the supercontinent Rodinia and the timing of its breakup. The tectonic history of the Arequipa Terrane is captured in a >4 km thick Cryogenian to early Cambrian succession on its western margin containing two Cryogenian diamictite and cap carbonate pairs, an Ediacaran carbonate-dominated passive margin developed across a west-facing hinge zone, and overlain by a late Ediacaran to early Cambrian foreland basin. The lithostratigraphy, timing of basin formation events, and provenance of the succession suggest rift-related linkages between the Kalahari craton and southeastern Laurentia. Thus, we propose that the Arequipa Terrane shared successful Tonian-Cryogenian rifted margins with Kalahari and southeastern Laurentia, was an isolated terrane in the Ediacaran, and collided with southwestern Amazonia in the late Ediacaran to early Cambrian Pampean Orogeny. The tectonic history of the Arequipa Terrane is consistent with Tonian-Cryogenian breakup of Rodinia, fails to support a late Ediacaran to early Cambrian rift-related linkage to southern or eastern Laurentia, and does not support the existence of the supercontinent Pannotia.