The Andrelândia succession comprises six lithofacies associations, from base to top, represented by: A1-paragneiss; A2paragneiss, quartzite and schist; A3-quartzite; A4-grey phyllite/schist; A5-biotite schist/gneiss; A6-paragneiss, metachert and calc-silicate rocks. Amphibolite bodies are common in the A1, A2 and A6 associations. They represent continental and oceanic tholeiitic magmatism generated during the basin evolution. The vertical and horizontal distribution of these lithofacies suggest transgressive and regressive depositional systems of common intraplate continental margin paleoenvironments, probably including continental (A1), coastal plain-platform (A2, A3, A4, A6), submarine fan and basin plain deposits (A5,A6). The lithofacies associations and the mafic magmatism also reflect different stages of basin evolution from rifting (A1) to proto-oceanic (A2, A6) and mature continental margin stages (A3, A4, A5, A6). This continental margin had its paleocoastline oriented NW-SE and depocenter to WSW as indicated by the regional distribution of the quartzitic and pelitic lithofacies. The basin opening is related to a world-wide taphrogenic event that started at circa 1,000 Ma. The Andrelândia Basin comprises the intraplate continental margins between the São Francisco plate and the Paraná Block. The basin closure took place in two subsequent collisional stages during the Brasiliano Orogeny that resulted in the Brasília Belt and the Central Segment of the Ribeira Belt.

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-The South Orkney Islands are the exposed part of a continental fragment on the southern limb of the Scotia arc. The islands are to a large extent composed of metapelites and metagreywackes of probable Triassic sedimentary age. Deformation related to an accretionary wedge setting, with associated metamorphism from anchizone to the greenschist facies, are of Jurassic age (176-200 Ma). On Powell Island, in the centre of the archipelago, five phases of deformation are recognized. The first three, associated with the main metamorphism, are tentatively correlated with early Jurassic subduction along the Pacific margin of Gondwana. D 4 is a phase of middle to late Jurassic crustal extension associated with uplift. This extension phase may be related to opening of the Rocas Verdes basin in southern Chile, associated with the breakup of Gondwanaland. Upper Jurassic conglomerates cover the metamorphic rocks unconformably. D 5 is a phase of brittle extensional faulting probably associated with Cenozoic opening of the Powell basin west of the archipelago, and with development of the Scotia arc.

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São apresentados os resultados do estudo de um perfil geológico realizado ao longo da rodovia Melo-Centurion, no Uruguai, em afloramentos da Formação Yaguari. O Membro Inferior desta unidade é dominantemente pelítico enquanto o Superior apresenta-se essencialmente arenoso, exibindo laminação planoparalela e estratificações cruzadas de pequeno a grande porte. O Membro Superior inclui também níveis de conglomerados intraformacionais, onde são encontrados fragmentos ósseos muito semelhantes aos que ocorrem na Formação Sanga do Cabral (Triássico Inferior) do Estado do Rio Grande do Sul. O Membro Inferior mais a parte basal do Membro Superior apresenta claras afinidades litológicas e de posicionamento estratigráfico com a Formação Rio do Rasto que aflora na rodovia Bagé-Aceguá; o Membro Superior, por sua vez, corresponde à Formação Sanga do Cabral. Em vista da correspondência traçada acima e da falta de evidências de um hiato sedimentar maior, o limite Permo-Triássico na região parece ser claramente gradacional.