The Neoproterozoic glacial record in the Río de la Plata Craton: a critical reappraisal
Published:January 01, 2008
P. J. Pazos, L. S. Bettucci, J. Loureiro, 2008. "The Neoproterozoic glacial record in the Río de la Plata Craton: a critical reappraisal", West Gondwana: Pre-Cenozoic Correlations Across the South Atlantic Region, R. J. Pankhurst, R. A. J. Trouw, B. B. de Brito Neves, M. J. de Wit
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Neoproterozoic glacial successions have been described in South America, but the glacial deposits of the Río de la Plata Craton have been neglected in previous studies addressing the global distribution of glacially influenced successions. The Río de la Plata Craton contains Neoproterozoic glacial deposits in the Sierra del Volcán Formation (Tandilia System, Argentina), glacial influenced deposits in the Playa Hermosa and Zanja del Tigre formations (Dom Feliciano Belt, Uruguay) and suspected glacially influenced deposits in Passo da Areia (São Gabriel block, Brazil). The Tandilia System glacial record includes diamictites, dropstones and rhythmites deposited in glaciomarine conditions in a tectonically stable depositional setting. The Dom Feliciano Belt includes a thin section with ice-rafted clasts in carbonates and a thicker section containing diamictites, rhythmites, outsized clasts and deformed beds in a volcano-sedimentary succession. The São Gabriel block occurrence deserves more attention to confirm any glacial influence in the fine-grained part of the succession. Glaciation is considered to be contemporaneous with the Gaskiers glaciation (580 Ma), with the exception of the carbonates with dropstones that may represent a previous event correlative with one of the glaciations described in the Kalahari Craton, prior to Kalahari–Río de la Plata assembly in the proto-western Gondwana margin.
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West Gondwana: Pre-Cenozoic Correlations Across the South Atlantic Region
Some 75 years after the visionary work of Wegener and du Toit, Neoproterozoic to Mesozoic geological correlations between South America and Africa are re-examined in the light of plate tectonics and modern geological investigation (structural and metamorphic studies, stratigraphic logging, geochemistry, geochronology and palaeomagnetism). The book presents both reviews and new research relating to the shared Gondwana origins of countries facing each other across the South Atlantic Ocean, especially Brazil, Argentina, Cameroon, Nigeria, Angola, Namibia and South Africa. This is the first comprehensive treatment to be readily available in book form. It covers the common elements of cratonic areas pre-dating Gondwana, and how they came together in late Precambrian and Cambrian times with the formation of the Pan-African/Brasiliano orogenic belts (Dom Feliciano, Brasília, Ribeira, Damara, Gariep, Kaoko, etc.). The subsequent shared Palaeozoic and Mesozoic sedimentary record (Karoo system) prior to Gondwana break-up is also reviewed.