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The Río de la Plata Craton (RPC) comprises part of southern Brazil, Paraguay, Uruguay and the central-eastern sector of Argentina. To the north, the RPC is bounded by the southern Amazonian craton, whereas to the east it is bounded by the allochthonous Cuchilla Dionisio Terrane. The RPC is limited in the west by the Pampia Terrane of Argentina. Three tectono-stratigraphic terranes compose the RPC: the Piedra Alta, Tandilia and Nico Pérez terranes, separated by the first-order Sarandí del Yí and Colonia shear zones. Basement rocks range in age from Archaean to Mesoproterozoic, with Palaeoproterozoic igneous–metamorphic complexes making up most of the Tandilia and Piedra Alta terranes. Neoproterozoic (mainly Ediacaran) sedimentary successions occur in the three terranes, and mainly represent passive margin deposits. Abundant granitic intrusions between 630 and 530 Ma in the Nico Pérez Terrane may represent rift-related granitoids or a transpressive regime with subduction towards the north-northwest during the Brasiliano Cycle. Fil: Bossi, Jorge. Universidad de la República; Uruguay Fil: Cingolani, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina

Neoproterozoic palaeoclimate in the Río de la Plata Craton (RPC) can be understood in terms of a warm, possibly tropical, “background” climate punctuated by several cold or even glacial events. Evidences of a dominantly tropical palaeoclimate are: (1) Thick carbonate deposits blanketed the marginal areas of the RPC in the Neoproterozoic, beginning in the late Mesoproterozoic-Tonian (Mina Verdún Group) and especially in the late Ediacaran-Early Cambrian (Sierras Bayas and Arroyo del Soldado groups). (2) Clay minerals derived from the granitic-metamorphic basement were predominantly kaolinitic during certain periods. (3) Preliminary palaeomagnetic data suggest a tropical latitude for the late Ediacaran and Early Cambrian. On the other hand, clear evidences of ice-rafting and glacially-influenced deposits were reported from the Playa Hermosa and Las Ventanas formations, which could be lateral equivalents. These evidences will be discussed in detail below. Fil: Gaucher, Claudio. Universidad de la República; Uruguay Fil: Poire, Daniel Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina

Neoproterozoic stromatolites were first recognised in the Río de la Plata Craton (RPC) by González Bonorino (1954) in the Sierras Bayas Group (Argentina). The first body fossils were also described from this unit by Fairchild (1978) and Pothe de Baldis et al. (1983), consisting of organic-walled microfossils (acritarchs). In Uruguay, Montaña and Sprechmann (1993) were the first to recognise Cambrian stromatolites in the Cerro Victoria Formation. The first report of Neoproterozoic body fossils (acritarchs) in Uruguay is due to Gaucher and Schipilov (1994) and Gaucher et al. (1996). Since these first reports, around a dozen papers appeared that deal with Neoproterozoic and Cambrian fossils in the RPC. The sedimentary successions deposited on and around the RPC record the existence of a diversified biota in Ediacaran times, including cyanobacteria, acritarchs, shelly fossils, stromatolites, trace fossils and –possibly- rare members of the Ediacara fauna. Fil: Gaucher, Claudio. Universidad de la República; Uruguay Fil: Poire, Daniel Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina