Sítio Baixa Grande – Nova Localidade Fossilífera Para a Formação Romualdo (Grupo Santana), Bacia Do Araripe

Abstract

ResumoUma nova localidade fossilífera, Sítio Baixa Grande, é descrita para a Formação Romualdo, Cretáceo Inferior do Nordeste do Brasil. Localizada próxima da área urbana da cidade de Potengi, na porção oeste da Bacia do Araripe, esse sítio foi descoberto em 2010 e apresenta diversidade e grande quantidade de fósseis. As concreções, de coloração bege a avermelhada, com formas regular e irregular, são facilmente encontradas sobre o solo. Apresentam forma ovoide, com textura pouco laminada. Os macrofósseis estão localizados na porção mediana da concreção, podendo apresentar também tridimensionalidade, uma feição comum aos fósseis da Formação Romualdo. Dentre os fósseis coletados estão tetrápodes, representados por ossos isolados de pterossauros e restos de tartarugas. Os peixes encontrados incluem: Vinctifer comptoni, Cladocyclus gardineri, Tharrhias araripis, Calamopleurus cilindricus e Neoproscinetes penalvai. Os fósseis aqui apresentados compreendem os únicos com localidade de coleta entre os encontrados na região oeste da Bacia do Araripe, uma área onde os afloramentos fossilíferos do Grupo Santana foram considerados como inexistentes. Dessa forma contribuindo para o conhecimento da distribuição de níveis fossilíferos dessa importante feição tectônica. Palavras-chave:Cretáceo. Concreções. Albiano. Tetrapoda. Ictiofósseis. THE BAIXA GRANDE SITE, A NEW FOSSIL LOCALITY OF THE LOWER CRETACEOUS ROMUALDO FORMATION (SANTANA GROUP) ARARIPE PLATEAU AbstractThe Baixa Grande Site, a new fossil locality of the Lower Cretaceous Romualdo Formation is described from Araripe Basin, northeast Brazil. Located around the urban area of the Potengy town, in the western portion of the Araripe Plateau, this locality was discovered in 2010 and shows a great diversity of fossils. The concretions have a beige to reddish coloration and are easily found laying on the ground. They show an ovoid shape, with low laminated texture. Macrofossils are mostly preserved in the middle ________ 1 .Professor,

An Unusual Fossiliferous Site in the Romualdo Formation in the Socorro Basin (Northeast Brazil)

“…Inst. Geociênc., 2023;46:57260 When comparing the fossils found in this new locality with the fossils prospected in the Romualdo Formation (Araripe Basin) in the state of Ceará, specifically at the Baixa Grande site in the municipality of Araripe (Saraiva et al 2016), its rocky matrix resembles the approximate size and shape (ovoid), with a slightly laminated texture.…”

“…Fossils from the Baixa Grande site included specimens of Vinctifer comptoni, Cladocyclus gardineri, Tharrhias araripis, Calamopleurus cylindricus, and Neoproscinetes penalvai that were preliminarily collected from the surface (Saraiva et al 2016), according to the classification proposed by Saraiva et al (2007). The concretions at the Baixa Grande site, which had a regular matrix and ovoid shape with a slightly laminated texture, are concretions containing one fossil; macrofossils are present in their median portion, they are generally compressed in appearance, and they may also have shown fossils in three dimensions, like the fossils found in our results.…”

“…Considering the coverage area of the Romualdo Formation, eventually, new fossiliferous areas are likely to be found (Saraiva et al 2016). Thus, this work describes a new fossiliferous site of this geological unit in the state of Pernambuco based on surface prospecting activities carried out in this region.…”

Mercury chemostratigraphy as a proxy of volcanic-driven environmental changes in the Aptian-Albian transition, Araripe Basin, northeastern Brazil

“…The Araripe Basin is located between the states of Ceará, Pernambuco and Piauí in northeastern Brazil (Fig. 1), comprising an area of approximately 9000 km 2 , being considered the most extensive sedimentary basin in northeastern Brazil (Assine, 1992;Valença et al, 2003;Neumann et al, 2008;Costa et al, 2014;Saraiva et al, 2016;Fabin et al, 2018). The geological history of this intracratonic basin began about 150 Ma ago and is associated with the separation of Gondwana and the opening of the South Atlantic (Ceará State Government, 2012).…”

“…The Crato Formation has a thickness of 50 m and overlies the Barbalha Formation that gradually changes into parallel, fine, horizontal laminated marls. This Formation, is well known because of its exceptionally well preserved fossil record, the most diversified fossil assemblage from the non-marine Cretaceous, including a large diversity of birds, insects, plants and even pterodactyls (Kellner 2002;Santana et al, 2013;Martill et al, 2007;Saraiva et al, 2015). Sediment deposition occurred during the Lower Cretaceous(~113-115 Ma), displaying a sequence of lacustrine limestone interbedded by siliciclastic facies, deposited in a saline lacustrine environment (Assine, 2007) or even a hypersaline lagoon with restricted connections to the sea (Varejão et al, 2016).…”