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The late Palaeozoic to Triassic sedimentary record of the central Argentinean offshore was analysed through the integration of data from exploratory wells and 2D seismic lines. Our interpretations were combined with existing ones in Argentina, Uruguay, Brazil and South Africa for their analysis in the late Palaeozoic south-western Gondwana context. The mapped upper Palaeozoic-Lower Triassic stratigraphic record offshore Argentina bears a thickness of +7.000 m south of the Colorado basin and encompasses the time span between Pennsylvanian and Lower Triassic; this means that it triples that of the Sierras de la Ventana of Argentina and involves a far larger time span. On the basis of seismic stratigraphic interpretations in localities near the coast, we interpret that a strong denudation process removed a Accepted ArticleThis article is protected by copyright. All rights reserved.great portion of the stratigraphic record in the Sierras de la Ventana, the surrounding plains and the Tandilia system of Buenos Aires. The seismic stratigraphic configuration of the late Palaeozoic succession shows continuous and parallel reflections in a wide sediment wedge extending for more than 1.000 km between the Gondwanides orogen core to the south and offshore Uruguay to the north. Two salient aspects of this sedimentary wedge are that no flexural depocentre was observed at the Ventania fold belt front, and that deformation in the orogenic front is post-Lower Triassic. The original westwards extent of the basin is interpreted to have encompassed the whole of Buenos Aires province in continuity with the Chacoparaná basin; to the east continuity and a straightforward correlation with the Karoo basin was interpreted. The name of Hespérides Basin (1) is proposed herein to refer to a Pennsylvanian to Lower Triassic basin mainly controlled by dynamic subsidence that encompasses and exceeds the area of the Sauce Grande and Colorado basins and the Claromecó fore-deep in Argentina. The Hespérides basin is interpreted to have been in lateral continuity with the Kalahari, Karoo and Chacoparaná basins of Africa and South America forming a +3,000,000 sq. km depocentre.Page footer: (1) Hespérides is one of the sons of Zeus, as Adamastor (the Neoproterozoic Ocean) and Atlantis (the Meso-Cenozoic Ocean), all them consecutive basins that opened in the Present South Atlantic. INTRODUCTION Foreword and objectivesThe Argentinean continental shelf between 35° and 42° S has a width ranging from 300 to 560 km that has represented a wide blank in the south-western Gondwana reconstructions; recent interpretations based on gravimetric and seismic data provide a comprehensive basement block configuration and tectonic evolution of the area integrated with both onshore Argentina and South Africa (Pángaro & Ramos 2012;Pángaro 2013). However, upper Palaeozoic sedimentary rocks known on the Argentinean continental shelf since the early 80s through exploratory drilling and 2D seismic interpretation (Uliana & Biddle 1987;Archangelsky 1996;Juan et al. 1996...

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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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