Cretaceous-Paleogene transition at the Paraíba Basin, Northeastern, Brazil: Carbon-isotope and mercury subsurface stratigraphies

Nascimento-Silva, Maria V.; Sial, Alcídes N.; Ferreira, Valderez P.; Neumann, Volker; Barbosa, José Antônio; Pimentel, Márcio Martins; Lacerda, Luiz Drude de

doi:10.1016/j.jsames.2011.02.014

Cited by 45 publications

(25 citation statements)

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“…11f- Jones 1996;Nascimento-Silva et al 2011). In thin sections, planar cuts of Dentalina alternata show the ridge ornaments of the striated shells and the spherical infilling of the foraminiferal chambers.…”

Section: Nature Of Calcitic and Phosphatic Spheroidsmentioning

confidence: 99%

The Cretaceous–Tertiary boundary (KTB) transition in NE Brazil

Gertsch¹,

Keller

Adatte

et al. 2013

JGS

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At 7800 km from Yucatan the Cretaceous-Tertiary boundary (KTB) transition of the Poty Quarry, NE Brazil, is the most distant locality with published accounts of Chicxulub impact-tsunami deposits, impact spherules and Ir anomaly. New investigations based on sedimentology, biostratigraphy, mineralogy and geochemistry fail to confirm these reports. Latest Maastrichtian planktic foraminiferal zones CF1 below an erosive and bioturbated disconformity and early Danian zone P1a(1) above indicate a short hiatus, with the KTB clay (zone P0), the Ir anomaly and the characteristic negative δ 13 C excursion missing. The disconformity coincides with the globally recognized latest Maastrichtian sea-level fall. Above the disconformity, an upward-fining micro-conglomerate with abundant reworked Cretaceous foraminifera, sub-angular phosphate clasts, calcitic and phosphatic spheroids along with an early Danian zone P1a(1) assemblage is interpreted as a gravity-flow deposit. Common spheroids throughout the late Campanian-Maastrichtian appear to be chamber infillings of the benthic foraminifer Dentalina alternata. Minor Ir anomalies in thin clay layers of zone Pla and no evidence of the Chicxulub impact reveal that the Poty Quarry section remains a very important example of the complex global environmental and sea-level changes observed in KT sequences from North America to Central America that are commonly misinterpreted as impact-tsunami events.Supplementary materials: Data for trace elements are available at www.geolsoc.org.uk/SUP18585. research-articleResearch Article170X10.1144/jgs2012-029B. GertschThe KTB Transition in NE Brazil 2013 at Mount Royal University on June 14, 2015 http://jgs.lyellcollection.org/ Downloaded from B. GERTSCH ET AL. 250 macrofossils were noted, described and photographed for the record.Poty Well-B and the quarry exposures were sampled at 3-5 cm intervals across the suspected KTB and at 5-10 cm intervals through an event deposit (described below), bioturbated intervals and the Danian. The Maastrichtian was sampled at 20 cm intervals. In the laboratory, samples were processed for foraminiferal extraction using standard methods .The PGE, and carbon and oxygen isotopes were analysed on powdered bulk-rock samples at the Institute for Mineralogy und Geochemistry, Karlsruhe Institute of Technology, Germany. PGE were measured by isotope dilution high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) after pre-concentration and matrix reduction by Ni-fire assay (Kramar et al. 2001). Carbon and oxygen isotope measurements were carried out using a Delta V Advantage ratio mass spectrometer equipped with an online carbonate preparation line (GasBench) with separate vials for each sample (Thermo Finnigan, Bremen, Germany). The results are expressed on the V-PDB scale with standard deviations <0.05% for δ 13 C and <0.1% for δ 18 O.Mineralogical analyses were carried out at the Geological Institute of the University of Neuchâtel, Switzerland. Bulk-rock and clay mineral assemblages were analysed by X-r...

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Section: Nature Of Calcitic and Phosphatic Spheroidsmentioning

confidence: 99%

The Cretaceous–Tertiary boundary (KTB) transition in NE Brazil

Gertsch¹,

Keller

Adatte

et al. 2013

JGS

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“…Sanei et al 17 demonstrated that the Siberian Trap eruption, the largest LIP in the geologic record and also associated with the largest Phanerozoic extinction event, left a characteristic mercury spike as a fingerprint in the rock record. Subsequent work has confirmed Hg spikes associated with other LIP events associated with mass extinction intervals [18][19][20][21][22][23] . Grasby et al 21 also demonstrated that background Hg levels appear constant over geologic time, showing that Hg spikes associated with LIPs are truly anomalous features of the rock record.…”

Section: Mercury As a Proxy For Lip Eventsmentioning

confidence: 84%

Mercury Spikes Suggest Volcanic Driver of the Ordovician-Silurian Mass Extinction

Qing¹,

Zhao²,

Wang³

et al. 2017

Geological Society of America Abstracts With Programs

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The second largest Phanerozoic mass extinction occurred at the Ordovician-Silurian (O-S) boundary. However, unlike the other major mass extinction events, the driver for the O-S extinction remains uncertain. The abundance of mercury (Hg) and total organic carbon (TOC) of Ordovician and early Silurian marine sediments were analyzed from four sections (Huanghuachang, Chenjiahe, Wangjiawan and Dingjiapo) in the Yichang area, South China, as a test for evidence of massive volcanism associated with the O-S event. Our results indicate the Hg concentrations generally vary in parallel with TOC, and that the Hg/TOC ratios remain low and steady state through the Early and Middle Ordovician. However, Hg concentrations and the Hg/TOC ratio increased rapidly in the Late Katian, and have a second peak during the Late Hirnantian (Late Ordovician) that was temporally coincident with two main pulses of mass extinction. Hg isotope data display little to no variation associated with the Hg spikes during the extinction intervals, indicating that the observed Hg spikes are from a volcanic source. These results suggest intense volcanism occurred during the Late Ordovician, and as in other Phanerozoic extinctions, likely played an important role in the O-S event.Refinements in radio-isotopic dating techniques has demonstrated a strong temporal link between Large Igneous Province (LIP) volcanism and four out of the five largest mass extinctions in the Phanerozoic, leading to suggestions that LIP events have devastating effects on global ecosystems that in some ways mirrors concerns over modern anthropogenic impacts on the planet [1][2][3][4] . The one anomaly is the Ordovician-Silurian (O-S) mass extinction, the second largest of the "Big Five" extinctions. In terms of species loss the O-S represented about 86% of marine life 5,6 , including the elimination of graptolites 7-9 and brachiopods 10, 11 . The triggering mechanism of the O-S mass extinction has been extensively debated, and various hypotheses have been proposed, including gamma ray burst and bolide impact 12,13 ; however, the cause still remains highly controversial. Intense Late Ordovician volcanism was also suggested as a potential extinction mechanism 14,15 , although no clear geologic record of a Late Ordovician LIP event has been demonstrated. The age of the event makes it possible that any geologic record has been lost 15 . Given this, we tested for indirect evidence of volcanism at the O-S extinction boundary by examining the Hg record from classic sections in south China. Here we show that significant spikes in Hg concentrations occur at the O-S extinction, along with Hg stable isotope data that indicate a volcanic source for these spikes. We suggest that this reflects Hg loading by a LIP event. If correct, these results demonstrate that LIP events have indeed played a critical role in the evolution of life through time. Mercury as a Proxy for LIP eventsVolcanic eruptions are the main natural source of Hg to the environment 16 . Sanei et al. 17 demonstrated that th...

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“…A história deposicional destas rochas começam com a Formação Beberibe, seguida pelas unidades Itamaracá, Gramame e Maria Farinha, acumuladas em uma rampa carbonática distal (Nascimento-Silva et al, 2011).…”

Section: Geologiaunclassified

Petrography of Reef Limestones of the Tambaba Formation (Eocene), Paraíba Basin, Brazil

Távora¹,

Dias²,

Filho

et al. 2017

Anuário IGEO UFRJ

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ResumoEste trabalho trata sobre a caracterização petrográfica dos calcários recifais da Formação Tambaba. Foi identificada a microfácies biomicrito dolomitizado nas camadas correspondentes ao estágio colonização de acreção recifal, enquanto no estágio diversificação as microfácies pelbiomicrito dolomitizado, biomicrito dolomitizado e biolitito dolomitizado (núcleo recifal), biomicrito dolomitizado (superfície de superposição recifal), biointramicrito e biointramicrito dolomitizado (flancos recifais). Por fim, no estágio domínio foi reconhecida a microfácies pelbiomicrito. Os depósitos carbonáticos recifais constituem uma sequência regressiva provavelmente formada em plataforma muito rasa em condições de baixo influxo de sedimentos, durante o estágio de estabilização do nível de base na posição mais baixa do nível do mar em sistema de trato baixo. Os recifes superpostos e a grande concentração de galerias icnofossilíferas sugerem que este pulso transgressivo foi marcado por lentas oscilações do nível do mar, influenciadas pela queda do nível eustático global, e eventos tectônicos locais nas sub-bacias Alhandra e Miriri. A baixa representatividade numérica fossilífera é resultante da ação intensa dos processos diagenéticos locais principalmente compactação mecânica, dolomitização, dedolomitização, dissolução na rocha como um todo pelos fluidos percolantes e dissolução local de CaCO 3 já precipitado nos poros, além da substituição de calcita por sílica, que dissolveram grande parte dos restos de espécimes da biocenose original. Os poucos elementos preservados parecem ser autóctones, representando a composição taxonômica original do recife, sugerindo que a biocenose não foi alterada significativamente. Palavras-chave: Formação Tambaba; microfácies deposicionais; recife AbstractThis work concerns with the detailed petrographic studies of the reef limestones of Tambaba Formation. A dolomitized biomicrite microfacies at colonization stage, dolomitized pelbiomicrite, dolomitized biomicrite and dolomitized biolithite (reef core), dolomitized biomicrite (superposition reef surface), biointramicrite and dolomitized biointramicrite (fore reef), all in diversification stage. Finally, in domination stage was defined the pelbiomicrite microfacies were identified. The reef carbonatic rocks constitute a regressive sequence deposited in shallow marine platform with low sedimentation rate during the establishment of a low stage. The superimposed reefs and ichnofossils content suggest sea level oscillations controlled by changes at global eustatic events and regional tectonic in Alhandra and Miriri sub-basins. The low quantity of biotic constituents explain the intense influence of the diagenetic processes: mechanical compaction, dolomitization, dedolomitization, dissolution and local dissolution of CaCO 3 precipitated in pores as well as replacement of the calcite by silica, that appears to have dissolved many specimens but the structure of the primary biocoenosis was preserved.

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Cretaceous-Paleogene transition at the Paraíba Basin, Northeastern, Brazil: Carbon-isotope and mercury subsurface stratigraphies

Cited by 45 publications

References 49 publications

The Cretaceous–Tertiary boundary (KTB) transition in NE Brazil

The Cretaceous–Tertiary boundary (KTB) transition in NE Brazil

Mercury Spikes Suggest Volcanic Driver of the Ordovician-Silurian Mass Extinction

Petrography of Reef Limestones of the Tambaba Formation (Eocene), Paraíba Basin, Brazil

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