Análise estratigráfica da Formação Brejo Santo, Bacia do Araripe, Nordeste do Brasil: implicações paleogeográficas

Fambrini, Gelson Luísa; Neumann, Volker; Barros, Cecília L.; Silva, Sonia Maria Oliveira Agostinho da; Galm, Paulo Cesar; Filho, José Acioli Bezerra de Menezes

doi:10.5327/z1519-874x201300040001

Cited by 20 publications

(29 citation statements)

References 11 publications

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“…A Formação Brejo Santo apresenta contato concordante e brusco com a unidade sobreposta (Fambrini et al, 2013), a Formação Missão Velha, e é correlata às formações Aliança da Bacia do Recôncavo, Tucano e Jatobá, Bananeiras da Bacia de Sergipe-Alagoas (Assine, 1992(Assine, , 2007Fambrini et al, 2011Fambrini et al, , 2012, bem como a contraparte africana, a Formação M'Vone da Bacia do Gabão (Teisserenc & Villemin, 1989;Mounguengui et al, 2008;Kuchle et al, 2011). Além das atividades de campo, a metodologia desta pesquisa inclui análises litofaciológica e mineralógica, além do estudo de macrofósseis e microfósseis, no qual os exemplares foram precedidos de preparação mecânica, e posteriormente identificados e classificados.…”

Section: Contexto Geológicounclassified

“…Apresenta-se intercalada com as demais litofácies lutíticas (L1, L2, L3, L5 e L6) e com a litofácies A3. É semelhante à litofácies Fsm de Miall (1996) e correlaciona-se, em parte, com as litofácies Fm de Fambrini et al (2012) e Fmm de Fambrini et al (2013).…”

Section: Litofácies L4 (Fsm)unclassified

“…Representa 7,7% de todos os afloramentos estudados na Formação Brejo Santo, estando intercalada com as litofácies L2, L3 e L4, com a litofácies A3 e com a litofácies C1. É semelhante à litofácies Fl de Miall (1996) e correlaciona-se, em parte, com a litofácies Fl de Fambrini et al (2012Fambrini et al ( , 2013.…”

Section: Litofácies L6 (Fl)unclassified

“…Apesar da análise litofaciológica sugerir que a unidade em estudo é um sistema fluvial, a Formação Brejo Santo é consagrada na literatura por diversos autores (Assine, 1992(Assine, , 2007Neumann et al, 2008;Barros, 2010;Barros et al, 2011;Kuchle et al, 2011;Carvalho & Melo, 2012;Fambrini et al, 2007Fambrini et al, , 2008Fambrini et al, , 2010aFambrini et al, , 2010bFambrini et al, , 2011Fambrini et al, , 2012Fambrini et al, , 2013 como pertencente a um sistema lacustre. Mais recentemente, Scherer et al (2014), caracterizaram a Formação Brejo Santo como composta por duas associações de litofácies distintas: de inundação fluvial e de planície de inundação distal.…”

Section: Interpretações Paleoambientais Para a Formação Brejo Santounclassified

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Sedimentary Environment of Brejo Santo Formation, Late Jurassic of Araripe Basin, Brazil

2018

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ResumoAtravés das análises litofaciológica e mineralógica dos afloramentos, foi realizada a interpretação paleoambiental para a Formação Brejo Santo, Jurássico Superior da Bacia do Araripe. Foram definidas três litofácies areníticas, uma carbonática e seis lutíticas, interpretadas como pertencentes a sistema fluvial meandrante. O predomínio de litofácies lutíticas de camadas vermelhas (red beds) evidencia a deposição em corpos d'água rasos de planície de inundação, devido às condições oxidantes, sujeitos a alta evaporação em clima árido a semi-árido, associados a momentos esporádicos de inundação fluvial (litofácies areníticas) devido ao extravasamento do canal principal em períodos de cheia. A presença recorrente de carbonato sugere que os corpos d'água eram salobros. O estudo mineralógico dos argilominerais revela mudanças de condições úmidas (presença de caulinita), na base, para condições predominantemente áridas a semi-áridas no topo, confirmada pela ocorrência mineralógica em associação de calcita, dolomita e palygorskita. Palavras-chave: Interpretação paleoambiental; sistema fluvial meandrante; planície de inundação AbstractThrough the lithofaciological and mineralogic analysis of outcrops, it was performed a depositional interpretation of Brejo Santo Formation, Late Jurassic of Araripe Basin. Three sandstone lithofacies were defined, one carbonatic and six lutitic, interpreted as pertaining to meandering fluvial system. The dominance of red bed lutitic lithofacies indicates the deposition in shallow water bodies of floodplain, due to oxidizing conditions, subject to high evaporation in arid to semi-arid climate, associated with sporadic moments of fluvial flooding (sandstone lithofacies) due to the extravasation of the main channel in periods of flood. The recurring presence of carbonate suggest that water from those water bodies was brackish. The mineralogical study of clay mineral, showed changes in the humidity conditions (presence of kaolinite) on the base, for predominantly arid to semi-arid conditions on top, confirmed by the mineralogical occurrence associated to calcite, dolomite and palygorskite.

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Section: Contexto Geológicounclassified

Section: Litofácies L4 (Fsm)unclassified

Section: Litofácies L6 (Fl)unclassified

Section: Interpretações Paleoambientais Para a Formação Brejo Santounclassified

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Sedimentary Environment of Brejo Santo Formation, Late Jurassic of Araripe Basin, Brazil

2018

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“…Its stratigraphic column spans Paleozoic and Mesozoic deposits (Upper Jurassic-Upper Cretaceous). The origin and geological evolution of the Mesozoic rocks of the Araripe Basin are related to the tectonic events that resulted in the Gondwana Supercontinent breakup, and the opening of the South Atlantic Ocean (Asmus and Ponte 1973;Asmus 1976, 1978;Matos 1992;Assine 1992;Mabesoone 1994;Ponte and Ponte-Filho 1996a, b;Matos 1999;Assine 2007;Fambrini et al 2008Fambrini et al , 2009Fambrini et al , 2011aFambrini et al , b, 2012bFambrini et al , 2013Scherer et al 2014). These events ended in the middle Cretaceous.…”

Section: Introductionmentioning

confidence: 99%

Facies architecture of the fluvial Missão Velha Formation (Late Jurassic–Early Cretaceous), Araripe Basin, Northeast Brazil: paleogeographic and tectonic implications

Fambrini

Neumann

Menezes-Filho

et al. 2017

Acta Geologica Polonica

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Sedimentological analysis of the Missão Velha Formation (Araripe Basin, northeast Brazil) is the aim of this paper through detailed facies analysis, architectural elements, depositional systems and paleocurrent data. The main facies recognized were: (i) coarse-grained conglomeratic sandstones, locally pebbly conglomerates, with abundant silicified fossil trunks and several large-to-medium trough cross-stratifications and predominantly lenticular geometry; (ii) lenticular coarse-to-medium sandstones with some granules, abundant silicified fossil wood, and large-to-medium trough cross-stratifications, cut-and fill features and mud drapes on the foresets of cross-strata, (iii) poorly sorted medium-grained sandstones with sparse pebbles and with horizontal stratification, (iv) fine to very fine silty sandstones, laminated, interlayered with (v) decimetric muddy layers with horizontal lamination and climbing-ripple cross-lamination. Nine architectural elements were recognized: CH: Channels, GB: Gravel bars and bed forms, SB: Sand bars and bedforms, SB (p): sand bedform with planar cross-stratification, OF: Overbank flow, DA: Downstream-accretion macroforms, LS: Laminated sandsheet, LA: Lateralaccretion macroforms and FF: Floodplain fines. The lithofacies types and facies associations were interpreted as having been generated by alluvial systems characterized by (i) high energy perennial braided river systems and (ii) ephemeral river systems. Aeolian sand dunes and sand sheets generated by the reworking of braided alluvial deposits can also occur. The paleocurrent measurements show a main dispersion pattern to S, SE and SW, and another to NE/E. These features imply a paleodrainage flowing into the basins of the Recôncavo-Tucano-Jatobá.

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A New Methodological Contribution for the Geodiversity Assessment: Applicability to Ceará State (Brazil)

Araujo

Pereira

2017

Geoheritage

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The concept of geodiversity aggregates the abiotic elements of nature and promotes the geoconservation. The main objective of this work is to contribute to the upgrade of the method for the assessment and quantification of geodiversity proposed by . The method is based on the superposition of a regular grid of 12 × 12 km on different maps (lithology, geomorphology, soil, paleonthology, mineral and geological energy resources) at scales of 1:250,000 to 1:600,000. In addition to other upgrades, the water resources are regarded here as a new component to consider when quantifying geodiversity. The sum of these maps generated the quantitative Map of Geodiversity Indices and the Map of Geodiversity Assessment, ranging from very low to very high geodiversity. The analysis of the geodiversity map of the State of Ceará (Brazil) shows the applicability and advantage of this method, highlighting two regions with higher levels of geodiversity (Northwest and South) and another region with the lowest levels (Sertões Cearenses). The results also allowed the characterization of the State of Ceará concerning the individual components of the geodiversity, especially the water resources. Geodiversity indices and maps are comprehensive and user-friendly data in the territorial planning, considering the geodiversity either as a whole, or each of its components, especially the more sensitive such as fossil conservation, and water, mineral, and nonrenewable energy resources management.

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Análise estratigráfica da Formação Brejo Santo, Bacia do Araripe, Nordeste do Brasil: implicações paleogeográficas

Cited by 20 publications

References 11 publications

Sedimentary Environment of Brejo Santo Formation, Late Jurassic of Araripe Basin, Brazil

Sedimentary Environment of Brejo Santo Formation, Late Jurassic of Araripe Basin, Brazil

Facies architecture of the fluvial Missão Velha Formation (Late Jurassic–Early Cretaceous), Araripe Basin, Northeast Brazil: paleogeographic and tectonic implications

A New Methodological Contribution for the Geodiversity Assessment: Applicability to Ceará State (Brazil)

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