The application of sequence stratigraphy concepts to continental deposits lacking the referece provided sea level has been a challenge, mainly because the temporal relationships between stratigraphic surfaces and systems tracts depend on the tectonic and climatic evolution of the area. Using the concept of accommodation space (A) and sediment supply (S), we identify specific stacking patterns of aeolian, lacustrine, fluvial and alluvial systems that correspond to the particular tectonic and climatic evolution of the southeastern portion of South America. With the end of the Early Cretaceous volcanism (133 Ma), the southeastern portion of South America underwent tectonic restructuring, which generated basins that encompassed continental sedimentary sequences. The tectonic events responsible for the accumulation of these sequences occurred during two primary phases. The first phase is related to Early Cretaceous thermal subsidence, which was more pronounced in the regions where the thickest Serra Geral Formation basaltic successions are found, resulting in the formation of Bauru Basin. The second phase was related to the Late Cretaceous uplift in southeastern Brazil as a result of magmatic/volcanic activity associated with the Trindade Mantle Plume. Stratigraphic analysis based on well-logs and outcrops and aided by petrographic studies identified three sequences that are bounded by regional unconformities that record important changes in the Bauru Basin's tectonic and paleoenvironmental conditions. The unconformity K-0 is related to the origin of the Bauru Basin in the Early Cretaceous. The Early Cretaceous Sequence 1 (Caiu a Group) is interpreted as a second-order sequence, formed by aeolian and fluvial deposits and constituting a Fluvial-Aeolian Systems Tract. Unconformity K-1 that was generated in the Late Cretaceous (Cenomanian -Campanian?) is related to the tectonic evolution of the basin and source area. Overlying Unconformity K-1, lacustrine, fluvial and alluvial deposits display progradational characteristics of the two-third-order sequences: Sequences 2A and 2B, constituted by the Fluvial-Lacustrine and Alluvial Systems Tracts, respectively, and separated by the Unconformity K-1A. Sedimentological characteristics, paleosols and stratigraphic architecture, suggest that A/S ratio was neutral in the late stage of the Sequence 1, whereas in the Sequence 2 there was an increase (Sequence 2A) followed by a decrease in the A/S ratio (Sequence 2B). Aeolian facies and paleosol P1 (Sequence 1), fluvial-lacustrine facies and hydromorphic soils (Sequence 2A), and alluvial facies and Paleosol P2 (Sequence 2B), indicate climatic changes in the South American during the Cretaceous. The stratigraphic framework, subaerial unconformities and paleosols provide key elements for subdividing of the Brazilian continental sequence into third-order sequences and systems tracts, for identification of allocyclic and autocyclic patterns in time and space.

Resumo Com o término das manifestações vulcânicas eocretáceas (133 Ma) a porção Sudeste da PlacaSul-americana passou por um processo de reestruturação tectônica gerando bacias que abrigaram sequências sedimentares continentais. Os eventos tectônicos responsáveis pelo acúmulo dessas sequências podem ser divididos em duas fases principais. A primeira fase está relacionada à subsidência termal eocretácea, que foi mais expressiva nas regiões onde se situam as maiores espessuras de basaltos da Formação Serra Geral, no centrooeste do Rio Grande do Sul, noroeste do Paraná e oeste do estado de São Paulo, responsável pela formação das bacias Jacuí e Caiuá. Já a segunda fase, na qual se originou a Bacia Bauru, deveu-se aos soerguimentos neocretáceos na região sudoeste de Minas Gerais e Sul de Goiás, resultantes das atividades magmáticas associadas à Pluma Mantélica de Trindade. As análises mostraram que a Bacia Caiuá (Eocretáceo) foi caracterizada por uma depressão cujo depocentro estaria localizado na porção mais ao sul em direção ao estado do Paraná e cujo limite norte se estendia até o Sudeste de Minas Gerais. Nessa época, o clima era árido atestado por uma sedimentação eólica. A Bacia Bauru, gerada no Neocretáceo, apresenta depocentro situado entre o oeste paulista e sudoeste mineiro, abrigando depósitos lacustres rasos (playa-lakes) e aluviais de clima árido a semi-árido, com características sedimentológicas e paleopedológicas sugestivas de condições climáticas mais úmidas. Os dados obtidos revelam a reestruturação tectônica ocorrida entre o Eo e Neocretáceo nessa porção da Placa Sulamericana, além de indicar variações do nível de base que influenciaram na evolução dos tratos de sistemas.Palavras-chave: Bacias Cretáceas, tratos de sistemas, nível de base, evolução tectônica. Abstract Framework and evolution of the Caiuá and Bauru Basins in the southest of Brazil. With

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In the last three decades, records of tribosphenidan mammals from India, continental Africa, Madagascar and South America have challenged the notion of a strictly Laurasian distribution of the group during the Cretaceous. Here, we describe a lower premolar from the Late Cretaceous Adamantina Formation, São Paulo State, Brazil. It differs from all known fossil mammals, except for a putative eutherian from the same geologic unity and Deccanolestes hislopi, from the Maastrichtian of India. The incompleteness of the material precludes narrowing down its taxonomic attribution further than Tribosphenida, but it is larger than most coeval mammals and shows a thin layer of parallel crystallite enamel. The new taxon helps filling two major gaps in the fossil record: the paucity of Mesozoic mammals in more northern parts of South America and of tribosphenidans in the Cretaceous of that continent. In addition, high-precision U-Pb geochronology provided a post-Turonian maximal age (≤87.8 Ma) for the type stratum, which is overlain by the dinosaur-bearing Marília Formation, constraining the age of the Adamantina Formation at the site to late Coniacian–late Maastrichtian. This represents the first radioisotopic age for the Bauru Group, a key stratigraphic unit for the study of Cretaceous tetrapods in Gondwana.