Long duration (&gt;4 Ma) and steady-state volcanic activity in the early Cretaceous Paraná–Etendeka Large Igneous Province: New palaeomagnetic data from Namibia

Dodd, Sarah C.; Niocaill, Conall Mac; Muxworthy, Adrian R.

doi:10.1016/j.epsl.2015.01.009

Cited by 66 publications

(49 citation statements)

References 46 publications

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“…Although a link between the Paraná-Etendeka igneous province and the Weissert Event has been suggested previously , available dates suggest that this is unlikely (e.g. Martinez et al, 2013), and that the environmental impacts of the volcanism were minimal due to its longevity (Dodd, Niocaill & Muxworthy, 2015). In the latest Barremian, the single largest volcanic province known on Earth was emplaced in the southwest Pacific, the Ontong Java Plateau (approximately 50 million km 3 ; Coffin & Eldholm, 1994).…”

Section: (4) Volcanismmentioning

confidence: 99%

“…However, the Otong Java Plateau volcanism is a strong candidate for the increase in sulphur toxicity. Instead, the Etendeka volcanic episode might have been responsible for a positive δ 13 C excursion and higher CO 2 levels throughout the Valanginian Weissert oceanic anoxic event , although the environmental impact might have been relatively small compared to other large-scale igneous events (Dodd et al, 2015). The potential impact that these dramatic events and clear environmental changes might have had on biotic patterns during the Late Jurassic and Early Cretaceous requires future investigation.…”

Section: (C) Additional Environmental Changes That Require Explorationmentioning

confidence: 99%

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Biotic and environmental dynamics through theLateJurassic–EarlyCretaceous transition: evidence for protracted faunal and ecological turnover

et al. 2016

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The Late Jurassic to Early Cretaceous interval represents a time of environmental upheaval and cataclysmic events, combined with disruptions to terrestrial and marine ecosystems. Historically, the Jurassic/Cretaceous (J/K) boundary was classified as one of eight mass extinctions. However, more recent research has largely overturned this view, revealing a much more complex pattern of biotic and abiotic dynamics than has previously been appreciated. Here, we present a synthesis of our current knowledge of Late Jurassic-Early Cretaceous events, focusing particularly on events closest to the J/K boundary. We find evidence for a combination of short-term catastrophic events, large-scale tectonic processes and environmental perturbations, and major clade interactions that led to a seemingly dramatic faunal and ecological turnover in both the marine and terrestrial realms. This is coupled with a great reduction in global biodiversity which might in part be explained by poor sampling. Very few groups appear to have been entirely resilient to this J/K boundary 'event', which hints at a 'cascade model' of ecosystem changes driving faunal dynamics. Within terrestrial ecosystems, larger, more-specialised organisms, such as saurischian dinosaurs, appear to have suffered the most. Medium-sized tetanuran theropods declined, and were replaced by larger-bodied groups, and basal eusauropods were replaced by neosauropod faunas. The ascent of paravian theropods is emphasised by escalated competition with contemporary pterosaur groups, culminating in the explosive radiation of birds, although the timing of this is obfuscated by biases in sampling. Smaller, more ecologically diverse terrestrial non-archosaurs, such as lissamphibians and mammaliaforms, were comparatively resilient to extinctions, instead documenting the origination of many extant groups around the J/K boundary. In the marine realm, extinctions were focused on low-latitude, shallow marine shelf-dwelling faunas, corresponding to a significant eustatic sea-level fall in the latest Jurassic. More mobile and ecologically plastic marine groups, such as ichthyosaurs, survived the boundary relatively unscathed. High rates of extinction and turnover in other macropredaceous marine groups, including plesiosaurs, are accompanied by the origin of most major lineages of extant sharks. Groups which occupied both marine and terrestrial ecosystems, including crocodylomorphs, document a selective extinction in shallow marine forms, whereas turtles appear to have diversified. These patterns suggest that different extinction selectivity and ecological processes were operating between marine and terrestrial ecosystems, which were ultimately important in determining the fates of many key groups, as well as the origins of many major extant lineages. We identify a series of potential abiotic candidates for driving these patterns, including multiple bolide impacts, several episodes of flood basalt eruptions, dramatic climate change, and major disruptions to oceanic systems. The J/K t...

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Section: (4) Volcanismmentioning

confidence: 99%

Section: (C) Additional Environmental Changes That Require Explorationmentioning

confidence: 99%

Biotic and environmental dynamics through theLateJurassic–EarlyCretaceous transition: evidence for protracted faunal and ecological turnover

et al. 2016

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“…3), from the Central Atlantic Magmatic Province (CAMP) at 200 Ma (Marzoli et al 1999), the Karoo event some 183-182 Ma ago (Riley et al 2004;Svensen et al 2012), the Etendeka LIPS between 135 and 130 Ma (Turner et al 1994;Dodd et al 2015), the Madagascar-Agulhas LIPS around 100 Ma within a greater southeast African LIP (Gohl et al 2011), and finally the Afar volcanism ϳ45 to 30 Ma ago (Hofmann et al 1997;Ershov and Nikishin 2004) further north and the subsequent northward migration of intraplate volcanism across the western Arabian plate and eastern Anatolia (Courtillot et al 1999;Faccenna et al 2013b;Gaina et al 2013). The Madagascar-Agulhas LIP, in particular, has been present offshore South Africa from ϳ140 to 95 Ma (Gohl et al 2011).…”

Section: Africa From Mantle Plumes To Subductionmentioning

confidence: 99%

Neo-Tethys geodynamics and mantle convection: from extension to compression in Africa and a conceptual model for obduction

et al. 2016

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Since the Mesozoic, Africa has been under extension with shorter periods of compression associated with obduction of ophiolites on its northern margin. Less frequent than “normal” subduction, obduction is a first order process that remains enigmatic. The closure of the Neo-Tethys Ocean, by the Upper Cretaceous, is characterized by a major obduction event, from the Mediterranean region to the Himalayas, best represented around the Arabian Plate, from Cyprus to Oman. These ophiolites were all emplaced in a short time window in the Late Cretaceous, from ∼100 to 75 Ma, on the northern margin of Africa, in a context of compression over large parts of Africa and Europe, across the convergence zone. The scale of this process requires an explanation at the scale of several thousands of kilometres along strike, thus probably involving a large part of the convecting mantle. We suggest that alternating extension and compression in Africa could be explained by switching convection regimes. The extensional situation would correspond to steady-state whole-mantle convection, Africa being carried northward by a large-scale conveyor belt, while compression and obduction would occur when the African slab penetrates the upper–lower mantle transition zone and the African plate accelerates due to increasing plume activity, until full penetration of the Tethys slab in the lower mantle across the 660 km transition zone during a 25 Myr long period. The long-term geological archives on which such scenarios are founded can provide independent time constraints for testing numerical models of mantle convection and slab–plume interactions.

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“…The province consists of a series of predominantly mafic lavas punctuated by some large volume silicic units with these units recording a number of reversals of Earth's magnetic field [ Dodd et al ., ; Marsh et al ., ; Milner et al ., ; Renne et al ., ]. We have recently produced a magnetostratigraphy for the bulk of the Etendeka province [ Dodd et al ., ] based on samples from 70 sites that produced high‐quality directional data. We used this information in our selection of 14 flows for paleointensity determinations.…”

Section: Ages and Samplingmentioning

confidence: 99%

“…The Paran a-Etendeka large igneous province was formed prior to the opening of the South Atlantic in the Early Cretaceous, and it is now exposed in South America and Africa [Peate, 1997]. The province consists of a series of predominantly mafic lavas punctuated by some large volume silicic units with these units recording a number of reversals of Earth's magnetic field [Dodd et al, 2015;Marsh et al, 2001;Milner et al, 1992;Renne et al, 1996]. We have recently produced a magnetostratigraphy for the bulk of the Etendeka province [Dodd et al, 2015] based on samples from 70 sites that produced high-quality directional data.…”

Section: Ages and Samplingmentioning

confidence: 99%

Paleointensity determinations from the Etendeka province, Namibia, support a low‐magnetic field strength leading up to the Cretaceous normal superchron

Dodd

Muxworthy

Niocaill

2015

Geochem. Geophys. Geosyst.

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Paleointensity estimates provide much needed information on field generation within Earth's core and upon the convective processes at work within the mantle. We present new paleointensity estimates from the early Cretaceous Etendeka large igneous province in Namibia (135Ma), which add to the sparse Southern Hemisphere data set. The Early Cretaceous marks an important change in the Earth's magnetic field from a state of rapid polarity reversals, to one of long-term stability associated with the onset of the Cretaceous Normal Superchron at 121 Ma. Paleointensity determinations, using the IZZI protocol, were carried out on a total of 172 specimens from 14 sites encompassing the exposed stratigraphy of the Etendeka province. Numerous checks of data reliability were considered before results were accepted, including partial thermoremanent magnetization (pTRM) checks and pTRM tail checks, hysteresis properties, thermomagnetic analyses, observations under reflected light, and changes to room-temperature susceptibility during the experiments. Following these checks, a total of 64 individual samples from five sites were considered to provide reliable paleointensity determinations. These results were combined to provide site mean data with an overall average virtual dipole moment (VDM) for the study of 2.5 6 1.0 3 10 22 Am 2 . This value equates to approximately 30% of present Earth's field and, when considered alongside existing studies, suggests that Earth's field strength was low in the time leading up to the Cretaceous normal superchron.

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Long duration (>4 Ma) and steady-state volcanic activity in the early Cretaceous Paraná–Etendeka Large Igneous Province: New palaeomagnetic data from Namibia

Cited by 66 publications

References 46 publications

Biotic and environmental dynamics through theLateJurassic–EarlyCretaceous transition: evidence for protracted faunal and ecological turnover

Biotic and environmental dynamics through theLateJurassic–EarlyCretaceous transition: evidence for protracted faunal and ecological turnover

Neo-Tethys geodynamics and mantle convection: from extension to compression in Africa and a conceptual model for obduction

Paleointensity determinations from the Etendeka province, Namibia, support a low‐magnetic field strength leading up to the Cretaceous normal superchron

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