Soft-sediment deformation structures in Aptian lacustrine laminites: Evidence of post-rift paleoseismicity in the Araripe basin, NE Brazil

Alencar, Márcio Lima; Filho, Osvaldo José Correia; Miranda, Tiago Siqueira de; Barbosa, José Antônio; Celestino, Maria Alcione Lima; Ramos, Germano Mário Silva; Araújo, Araly Fabiana Lima de; Neumann, Volker; Topan, João Gabriel; Roemers-Oliveira, Eduardo

doi:10.1016/j.jsames.2020.102955

Cited by 12 publications

(3 citation statements)

References 76 publications

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“…In addition, the presence of possible sismoslumps in "embombado" could mark changes in the vertical movement rates of lakes' substratum, indicating seismic activity in postrift deposits otherwise considered less, or nonaffected, by tectonic activity. Recently, Alencar et al (2021) suggested that these paleoseismic structures were probably associated with reactivation of the Patos shear zone.…”

Section: Facies Correlation Modelmentioning

confidence: 99%

Petrological Meaning of Ethnostratigraphic Units: Laminated Limestone of the Crato Formation, Araripe Basin, NE Brazil

et al. 2022

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Crato Formation, NE Brazil, consists of laminated limestones deposited in a lacustrine environment during the Early Cretaceous. The Nova Olinda Member, the lowest unit of the Crato Formation, is world-famous for their exceptionally well-preserved fossils. The Nova Olinda limestones have been economically exploited for centuries. Today, this commercial excavation still represents the main economic activity in the region. During the mining process, the quarry workers have developed an informal stratigraphic code to individualize the different beds in the quarries. Upward, the local workers recognize the succession as “lajão dos sete cortes”, “matracão", “lajão branco", “pão de milho”, “veio da paiba”, "veio doidão”, “lajão amarelo” and “veio do besouro”. Here, we used principles of ethnostratigraphy to verify the origin and validity of these informal stratigraphic nomenclatures by classifying them as ethnostra. For this, we applied a detailed petrographical analysis with thin sections and high-resolution X-ray techniques to characterize each ethnostratum. Our results suggest possible linkages between informal and formal stratigraphic nomenclatures in Nova Olinda Member. Finally, this study showed that ethnostratigraphy can be applied as an auxiliary tool in stratigraphic studies, in both, as an initial exploratory approach and as enhancing the relationship between the geologists and the local community.

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Section: Facies Correlation Modelmentioning

confidence: 99%

Petrological Meaning of Ethnostratigraphic Units: Laminated Limestone of the Crato Formation, Araripe Basin, NE Brazil

et al. 2022

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“…Therefore, the brittle–ductile SSDS at the top of FA‐4 are interpreted to be seismites ( sensu Seilacher, 1969). Other SSDS were previously identified in FA‐4 (Martill et al ., 2008; Miranda et al ., 2018; Alencar et al ., 2020), suggesting early extensional and compressional tectonics during sedimentation (Miranda et al ., 2018; Alencar et al ., 2020) of the strata below those described here. This tectonic event probably had some effect on the variation of the isotope values of this bed, which is accompanied by less evaporative conditions.…”

Section: Facies Associationsmentioning

confidence: 99%

Mixed siliciclastic–carbonate sedimentation in an evolving epicontinental sea: Aptian record of marginal marine settings in the interior basins of north‐eastern Brazil

et al. 2021

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The Aptian evaporitic transitional sequence (sag phase) of the Brazilian marginal basins records the first connection between the Central and South Atlantic oceans in the equatorial area. During this phase, lacustrine carbonate reservoirs and giant salt deposits developed in the southern basins of Santos and Campos, forming world-class petroleum reservoirs. The sag succession is also well-preserved in the interior rift basins of north-eastern Brazil, where upper Aptian strata are represented by a continuous section. This contribution presents an interpretation of the evolution of a third-order depositional sequence comprising lacustrine limestones, marine siliciclastic facies and evaporite deposits of the intracontinental Araripe Basin. The Lowstand Systems Tract is characterized by fluvial deposits filling accommodation generated during the syn-rift phase. The overlying deposits comprise marine facies with preservation of dinoflagellates and marine ichnotaxa, evidencing marine deposition in bayhead delta settings. The transgressive surface is represented by limestones, including the Konservat-Lagerst€ atte laminites, onlapping the basement rocks. Above, tide-dominated bay deposits with distinct subtidal, intertidal and supratidal portions are recorded. The Maximum Flooding Surface is a dark shale below foreshore to shoreface facies, marking the beginning of the Highstand Systems Tract, culminating with deposition of evaporites (gypsum and anhydrite). The stratigraphic architecture and palaeocurrents measured in different facies associations suggest that marine waters reached the basin from the south. The data unequivocally records late Aptian marine ingressions of an incipient South Atlantic Ocean over the interior basins of north-eastern Brazil, while lacustrine conditions were still prevailing in the Pre-Salt sag units of the Santos and Campos basins.

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“…Crevice is commonly found in soil sciences [5], geotechnics [6], and metallurgy [7]. Fracture and karst are other popular designations in reservoir engineering and geology groups [8][9][10]. Given this large onomastic spectrum, the term aperture is appropriate to denominate any of those crack events in the most generic mode since it can represent countless shapes observed both in pore-scale and macroscale, from small fissures to highly tortuous channels and seams.…”

mentioning

confidence: 99%

Irregularly-bounded cross sections’ shape factors from high-order piecewise-polynomials

Júnior

Oliveira

2023

Preprint

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In a two-dimensional domain, bounded cross-sections are interpretable from the generalized concept of “aperture” and embrace uncountable applications. Shapefactors for apertures confined by irregular boundaries are much less known than regular ones. Besides, they are poorly estimated due to restrictions in experimental measurements of underlying properties and do not have immediate determination. An example is the estimation of the Kozeny constant in models derived from the classical Kozeny-Carman equation. This paper presents a numerical Galerkinbasedintegral (GBI) model that computes shape factors for apertures confined by arbitrary boundaries, thus filling a knowledge gap regarding shape factor determination. The technique relies on two underlying pillars: accurate boundary reconstruction by high-order piecewise polynomials and shape factor recovery using the Poiseuille number. The GBI technique treats the fluid flow as fully developed under the laminar regime, thus allowing a reasonable comprehension of the cross-sectional dynamics. Our study stands on realistic apertures modeled from rock core samples and is additive to understanding transport mechanisms in fractured media. The outcomes are specifically helpful for people who deal with fluid injection of any kind and need to compute shape factors for ducts, fissures, or cracks, either for biotechnology, engineering, or medical applications.

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Soft-sediment deformation structures in Aptian lacustrine laminites: Evidence of post-rift paleoseismicity in the Araripe basin, NE Brazil

Cited by 12 publications

References 76 publications

Petrological Meaning of Ethnostratigraphic Units: Laminated Limestone of the Crato Formation, Araripe Basin, NE Brazil

Petrological Meaning of Ethnostratigraphic Units: Laminated Limestone of the Crato Formation, Araripe Basin, NE Brazil

Mixed siliciclastic–carbonate sedimentation in an evolving epicontinental sea: Aptian record of marginal marine settings in the interior basins of north‐eastern Brazil

Irregularly-bounded cross sections’ shape factors from high-order piecewise-polynomials

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