DEGEO - Departamento de Geologia

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/8

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2021 - 20222

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Autor: search.filters.author.Cerri, Rodrigo IrineuAssunto: search.filters.subject.U–Pb geochronology

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    Using detrital zircon and rutile to constrain sedimentary provenance of Early Paleozoic fluvial systems of the Araripe Basin, Western Gondwana.
    (2022) Cerri, Rodrigo Irineu; Warren, Lucas Veríssimo; Spencer, Christopher J.; Varejão, Filipe Giovanini; Promenzio, Paloma; Luvizotto, George Luiz; Assine, Mario Luis
    The Early Paleozoic of the NE Brazilian sedimentary basins are key to understanding the primeval depositional environments and paleogeography of Western Gondwana after its final assembly. In this context, determining the sedimentary provenance of the Early Paleozoic Cariri Formation (basal unit of the Araripe Basin) may improve paleogeographic reconstructions and stratigraphic correlations. Despite the Araripe Basin being one of the best-studied interior basins of northeastern Brazil, the Cariri Formation lacks detailed geochronological and sedimentary provenance analyses, which hamper precise definitions of its depositional age, sedimentary source areas and paleogeography. Considering this scenario, we performed a combined multiproxy approach, including sedimentologic and stratigraphic analysis, detrital zircon U–Pb dating and provenance studies based on trace elements in detrital rutile. The maximum depositional age for the Cariri Formation suggests that its sedimentation started after the Late Cambrian. Detrital zircon ages and detrital rutile provenance indicate that the primary source areas for the Cariri Formation fluvial system were the orogenic terranes related to the Brasiliano Orogeny, located at the SE of the Borborema Province (e.g., Sergipano Belt), with secondary, but also important, the contribution of Cambrian sources. Records of this event are also found in northern Africa, where units related to the Neoproterozoic East African-Antarctic and Pan African orogens provided sediments for basin-scale fluvial systems.
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    So close and yet so far : U–Pb geochronological constraints of the Jaibaras Rift Basin and the intracratonic Parnaíba Basin in SW Gondwana.
    (2021) Cerri, Rodrigo Irineu; Warren, Lucas Veríssimo; Varejão, Filipe Giovanini; Silva, Alex Joaquim Choupina Andrade; Lana, Cristiano de Carvalho; Assine, Mario Luis
    Several sag-type basins apparently developed from rift systems, but there is no consensus about how and if these grabens influenced the sedimentation of the post-rift thermal subsidence phase. The Ediacaran Jaibaras Rift Basin is one of the best-exposed sedimentary records among the NE Brazil late Precambrian – early Cambrian rift system, cropping out at the eastern margin of the intracratonic Parnaíba Basin and extending below it towards the west. Here we present detrital zircon U–Pb ages of rocks from the Jaibaras (Aprazível Formation) and Parnaíba (Ipu Formation) basins, in order to understand the provenance patterns, maximum depositional ages (MDA) and age relationship between these units. The MDA for the Aprazível Formation (c. 499 ± 5 Ma) indicates a Cambrian age for the upper part of the Jaibaras Basin. The bulk U–Pb data indicate that the Ipu Formation started to deposit during late Cambrian and/or Early Ordovician time, despite its MDA (c. 528 ± 11 Ma) being older than that of the Aprazível Formation. Detrital zircon provenance suggests that the primary source areas for the early deposits of the Parnaíba Basin were mountains related to the Brasiliano Orogeny to the south and SE (e.g. Rio Preto and Riacho do Pontal metamorphic belts). Finally, our data emphasize the key change in source areas from the rift to the initial deposition of the intracratonic phase, indicating major depositional style changes between both basins after the Gondwana assembly.