High-precision geochronology links the Ferrar large igneous province with early-Jurassic ocean anoxia and biotic crisis

Burgess, Seth D.; Bowring, Samuel A.; Fleming, Thomas H.; Elliot, David H.

doi:10.1016/j.epsl.2015.01.037

Cited by 245 publications

(115 citation statements)

References 60 publications

(118 reference statements)

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“…Existing U-Pb dates from the Umkondo LIP are quite close together in age implying the the province was emplaced rapidly (within ca. 3 million years) as is the case for some other well-constrained intraplate large magmatic events such as the Central Atlantic Magmatic Province (Blackburn et al, 2013) and the Karoo-Ferrar Province (Sell et al, 2014;Burgess et al, 2015). Notably, this magmatic history contrasts with the evidence for prolonged magmatic activity in the Keweenawan Midcontinent Rift wherein applications of paleosecular variation analyses need to be cognizant of the evidence for progressive directional change that is associated with rapid plate motion rather than secular variation (Davis & Green, 1997;Swanson-Hysell et al, 2009, 2014a.…”

Section: Paleosecular Variationmentioning

confidence: 79%

A new grand mean palaeomagnetic pole for the 1.11 Ga Umkondo large igneous province with implications for palaeogeography and the geomagnetic field

Swanson‐Hysell¹,

Kilian²,

Hanson

2015

Geophysical Journal International

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corresponds with a normal or reversed geomagnetic field relative to other continents can constrain the relative orientations between cratons with time-equivalent data. This interpretation is particularly important in comparison to Laurentia as it bears on Kalahari's involvement and position in the supercontinent Rodinia. The dominance of south-directed declinations within the Umkondo Province was previously used to suggest that these directions are the same polarity as reversed directions from the early magmatic stage of the Keweenawan Midcontinent Rift of Laurentia. Two Umkondo sills with northerly declinations have U-Pb baddeleyite ages of ca. 1109Ma that are temporally close to dated Midcontinent rift units having reversed directions. Based on this comparison, and paleomagnetic data from younger units in the Kalahari Craton, we favor the option in which the sites with northerly declinations from the Umkondo Province correspond to the reversed polarity directions from the early magmatic stage in the Midcontinent Rift. This interpretation allows for the Namaqua-Natal metamorphic belt of Kalahari to be a conjugate to the Grenville margin of North America and for Kalahari to have become conjoined with Laurentia within the supercontinent Rodinia subsequent to Umkondo LIP magmatic activity. IntroductionPaired paleomagnetic and geochronologic data demonstrate that between ca. 1112 and 1108 Ma there was large-scale magmatism across the Kalahari Craton over an area of ∼2 x 10 6 km 2 ( Fig. 1; Hanson et al., 2004a). Extrusive components of this province are exposed as tholeiitic basalts that occur at the top of the Umkondo Group in Zimbabwe and Mozambique (Swift, 1962;McElhinny, 1966;Moabi et al., 2015) and as rhyolite lavas, pyroclastics and tholeiitic basalts within the Kgwebe Formation of northern Botswana (Modie, 1996;Hanson et al., 2006). However, the majority of exposed remnants of the Umkondo Large Igneous Province (LIP) are shallow-level mafic intrusions de Kock et al., 2014) which are interpreted as feeders to more extensive flood lavas that have largely eroded away (Hanson et al., 2004a).The widespread extent of these intrusions has led to the inference that the lavas covered nearly Swanson-Hysell et al. (2015) (2011) for sources for the geological data. The inset map shows the location of the main map and the broader geological context. The thick translucent gray line on the inset map indicates the interpreted shape of the Kalahari Craton on the interior of the late Mesoproterozoic orogenic belts that is used in the paleogeographic reconstructions (Fig. 4) (Hanson et al., 2004bSöderlund et al., 2010), post-1.83 Ga dolerite sills in the Soutpansberg Group (Brandl, 1981(Brandl, , 1985Geng et al., 2014), and the widespread 0. basement correspond to the Umkondo event is a reasonable one, it is largely untested since there are precise age constraints for only a small fraction of the total exposed intrusions. If high-quality paleomagnetic data can be generated from a given sill, the distinct paleomagnetic poles ...

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Section: Paleosecular Variationmentioning

confidence: 79%

A new grand mean palaeomagnetic pole for the 1.11 Ga Umkondo large igneous province with implications for palaeogeography and the geomagnetic field

Swanson‐Hysell¹,

Kilian²,

Hanson

2015

Geophysical Journal International

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“…The entire T-OAE isotopic excursion has been estimated as lasting 0.3-0.5 myr (Boulila et al 2014) or 0.6 ± 0.1 myr (Huang & Hesselbo 2014), with the two major anoxic episodes, termed T-OAE1 and T-OAE2, falling on either side of the 183 Ma age estimate (Ikeda & Hori 2014;Sell et al 2014). The substantial carbon isotopic anomaly has been explained by input of large volumes of isotopically light carbon from the Karoo-Ferrar basaltic province (Suan et al 2010;Burgess et al 2015).…”

Section: A Time Of Environmental Crisismentioning

confidence: 99%

The Strawberry Bank Lagerstätte reveals insights into Early Jurassic life

Williams

Benton

Ross

2015

JGS

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“…However, large igneous provinces associated with the arrival of upwelling mantle plumes often result in short (~1 m.y.) pulses of intense and voluminous volcanism (e.g., Blackburn et al, 2013;Burgess et al, 2015;Renne et al, 2015). In contrast, magmatism in the Midcontinent Rift was prolonged over tens of millions of years.…”

Section: Introductionmentioning

confidence: 99%

The End of Midcontinent Rift Magmatism and the Paleogeography of Laurentia

Fairchild

Swanson‐Hysell

Ramezani

et al. 2016

Geological Society of America Abstracts With Programs

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Paleomagnetism of the North American Midcontinent Rift provides a robust paleogeographic record of Laurentia (cratonic North America) from ca. 1110 to 1070 Ma, revealing rapid equatorward motion of the continent throughout rift magmatism. Existing age and paleomagnetic constraints on the youngest rift volcanic and sedimentary rocks have been interpreted to record a slowdown of this motion as rifting waned. We present new paleomagnetic and geochronologic data from the ca. 1090-1083 Ma "late-stage" rift volcanic rocks exposed as the Lake Shore Traps (Michigan), the Schroeder-Lutsen basalts (Minnesota), and the Michipicoten Island

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High-precision geochronology links the Ferrar large igneous province with early-Jurassic ocean anoxia and biotic crisis

Cited by 245 publications

References 60 publications

A new grand mean palaeomagnetic pole for the 1.11 Ga Umkondo large igneous province with implications for palaeogeography and the geomagnetic field

A new grand mean palaeomagnetic pole for the 1.11 Ga Umkondo large igneous province with implications for palaeogeography and the geomagnetic field

The Strawberry Bank Lagerstätte reveals insights into Early Jurassic life

The End of Midcontinent Rift Magmatism and the Paleogeography of Laurentia

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