Jéssica de Souza Gabi Barcellos

The Trans-Amazon Drilling Project (TADP) is reconstructing the late Cenozoic history of Amazonian geology, climate, rivers, and forests. Drilling in the Acre Basin of western Brazil in 2023 recovered an 860 m drill core characterized by sediments that were deposited in a large paleo-river system. The overall sequence includes sandstones, siltstones, and mudstones that underwent varied degrees of weathering and pedogenesis. Here, we describe the ongoing geochronologic, geochemical, mineralogical, geophysical, and biotic analyses of the sedimentary record and present some preliminary inferences of the environmental history based on these initial results. Except for the uppermost ∼ 12 m, sediments from the drill core represent a single lithostratigraphic unit, assigned to the Solimões Formation, which is dominated by feldspar-rich sands of Andean origin. The pollen assemblage is quite different from Early to Middle Miocene floras that have been analyzed from a few sites elsewhere in the western Amazon. The novel pollen assemblage and new geochronological results suggest that the sequence may span the latest Miocene and all of the Pliocene Epoch, an interval that currently is not well represented in existing regional records and that is crucial for understanding the evolution of Amazonian biodiversity, as well as landscape transformations driven by Andean uplift and global climate change.

Clay mineral assemblages (CMA) provide important records of paleoclimatic variability in sedimentary basins. Unlike authigenic clay minerals formed during diagenesis, detrital clays are transported from continental source areas and reflect weathering and sedimentary processes linked to climatic conditions. This study examines the Paleozoic evolution of the Parnaíba Basin (Brazil) based on clay mineral composition, with emphasis on detrital kaolinite as a proxy for precipitation. Mineralogical data from the clay fraction were integrated with estimates of mean annual air temperature (MAAT) and mean annual precipitation (MAP). Silurian units are characterized by assemblages dominated by illite and smectite, with MAAT values between 7 and 9 °C and MAP between 200 and 600 mm/yr, consistent with reduced chemical weathering under icehouse conditions. In the Devonian, kaolinite becomes more abundant, accompanied by MAP values ranging from 800 to 1200 mm/yr, suggesting intensified precipitation and enhanced continental weathering. This pattern contrasts with the Permian interval, where kaolinite contents decrease and MAP values fall to 0–400 mm/yr, reflecting progressive aridization associated with the paleogeographic configuration of western Gondwana during the assembly of Pangea. Considered together with paleogeographic reconstructions, these variations coincide with shifts in paleolatitudinal position and associated changes in precipitation distribution. The increase in kaolinite during the Devonian and its reduction in the Permian follow the same general trend observed in the climatic parameters. The distribution of detrital kaolinite records variations in precipitation and the intensity of continental chemical weathering, reinforcing its potential as a paleoclimatic proxy in intracratonic basins throughout the Paleozoic.

O artigo analisa a relação entre interseccionalidade de gênero, raça e classe e insegurança hídrica, evidenciando a segregação socioespacial e ambiental na cidade de São Paulo. A justificativa reside no fato de que as desigualdades socioespaciais, a atomização do cuidado e a privatização dos serviços públicos vêm tornando o acesso ao saneamento ambiental básico cada vez mais precário, e, portanto, um debate urgente. Foi utilizada uma metodologia quali-quantitativa que faz uso de métodos estatísticos e de geoprocessamento. Como as mulheres são responsabilizadas pelos trabalhos reprodutivo e de cuidados na rotina familiar, acabam sendo, também, responsáveis pela gestão hídrica doméstica, tendo em vista a necessidade de água para a realização dessas tarefas. Assim, a segregação socioespacial e a ausência de saneamento básico, marcadas pelos fatores étnico-raciais e de classe, afetam principalmente as mulheres, revelando o caráter racista e patriarcal das desigualdades socioambientais presentes no espaço urbano em São Paulo.