Isotopes to ice: constraining provenance of glacial deposits and ice centers in west-central Gondwana

• Autores: Griffis, Neil; Montañez, Isabel Patricia; Fedorchuk, Nicholas D.; Isbell, John; Mundil, Roland; Vesely, Fernando; Weinschütz, Luis; Iannuzzi, Roberto; Gulbranson, Erik L.; Taboada, Arturo Cesar; Pagani, María Alejandra; Sanborn, Matthew E.; Huyskens, Magda; Wimpenni, Josh; Linol, Bastien; Qing zhu, Yin
• Año de publicación: 2017
• Idioma: inglés
• Tipo de recurso: documento de conferencia
• Materia: ISOTOPES; LPIA; WEST-CENTRAL GONDWANA; GLACIAL DEPOSITS
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

The timing and geographic distribution of glaciers in high-latitude southern Gondwana during the late Paleozoic Ice Age remain poorly constrained, ultimately precluding our ability to estimate ice volume and associated climate teleconnections and feedbacks during Earth’s penultimate icehouse. Here, we report new U-Pb ages and Hf isotope compositions of detrital zircons recovered from diamictites in two key mid- to high-latitude Gondwanan basins (Paraná, Brazil and Tepuel, Argentine Patagonia). The results indicate regional sediment sources for both basins during the early period of late Paleozoic glaciation evolving into more distal sources during the final phase of deglaciation along southern and western Gondwana. Similar age sediment sourced from diamictites in the Congo Basin, that require an ice center in eastern Africa suggest the possibility of a large ice sheet in this area of Africa proximal to the Carboniferous-Permian boundary, which may have sourced sediments to the Paraná Basin. An inferred distal southern source of glacial sediment for the Tepuel Basin argues for the presence of an ice sheet(s) in the Ellsworth block of Antarctica towards the end of the glaciation history in Patagonia. These findings indicate an evolution during the late Paleozoic Ice Age from proximally to extrabasinally sourced sediment reflecting continental-scale glaciation and subsequent drainage from the Windhoek Highlands, Ellsworth Block and an East African source in west-central Gondwana. Coincidence with a long-term fall in atmospheric pCO2 during the Pennsylvanian to a minimum across the Carboniferous-Permian boundary and a subsequent rise in the early Permian suggests a primary CO2-driver for deglaciation in the Paraná Basin. Additional boundary conditions including availability of moisture and paleogeography likely further contributed to the timing of nucleation, growth and demise of these Gondwanan glaciers.
Fil: Griffis, Neil. University of California; Estados Unidos
Fil: Montañez, Isabel Patricia. University of California; Estados Unidos
Fil: Fedorchuk, Nicholas D.. University of Wisconsin; Estados Unidos
Fil: Isbell, John. University of Wisconsin; Estados Unidos
Fil: Mundil, Roland. Berkeley Geochronology Center; Estados Unidos
Fil: Vesely, Fernando. Universidade Federal do Paraná; Brasil
Fil: Weinschütz, Luis. Universidade Do Contestado; Brasil
Fil: Iannuzzi, Roberto. Universidade Federal do Rio Grande do Sul; Brasil
Fil: Gulbranson, Erik L.. University of Wisconsin; Estados Unidos
Fil: Taboada, Arturo Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina
Fil: Pagani, María Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina. Museo Paleontológico Egidio Feruglio; Argentina
Fil: Sanborn, Matthew E.. University of California; Estados Unidos
Fil: Huyskens, Magda. University of California; Estados Unidos
Fil: Wimpenni, Josh. University of California; Estados Unidos
Fil: Linol, Bastien. Nelson Mandela University; Sudáfrica
Fil: Qing zhu, Yin. University of California; Estados Unidos
Geological Society of America Annual Meeting
Seattle
Estados Unidos
Geological Society of America