A paleomagnetic and U–Pb geochronology study of the western end of the Grenville dyke swarm: Rapid changes in paleomagnetic field direction at ca. 585Ma related to polarity reversals?

Halls, H. C.; Lovette, Alan; Hamilton, M. A.; Söderlund, Ulf

doi:10.1016/j.precamres.2014.11.029

Cited by 60 publications

(35 citation statements)

References 45 publications

(79 reference statements)

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“…There is a >200 Ma gap in reliable Laurentian paleomagnetic data between ~1000 and ~790 Ma, followed by another ~100 Ma gap between ~720 and 615 Ma (e.g., Pisarevsky et al, 2008;Pisarevsky et al, 2003). Later (>615 Ma) Ediacaran Laurentian paleopoles are controversial (e.g., Halls et al, 2015;McCausland et al, 2011), but they all suggest that Rodinia had already broken up . Consequently paleopositions of Laurentia are paleomagnetically well constrained for the initial (>1000 Ma) stages of the Rodinian assembly, and for the time of…”

Section: East and Southeast Laurentia -Grenville Orogenmentioning

confidence: 99%

Laurentia-Baltica-Amazonia relations during Rodinia assembly

Cawood

Pisarevsky

2017

Precambrian Research

146

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Section: East and Southeast Laurentia -Grenville Orogenmentioning

confidence: 99%

Laurentia-Baltica-Amazonia relations during Rodinia assembly

Cawood

Pisarevsky

2017

Precambrian Research

146

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“…The apparent polar wander paths (APWP) of Laurentia, one of the most populated data sets, is divided into two groups of coeval paleomagnetic poles offset by some 90°. Various hypotheses were proposed in the literature to explain these data, involving the presence of unreliable paleomagnetic data or datings (e.g., Hodych et al, 2004), a nonuniformitarian magnetic field (Abrajevitch & Van der Voo, 2010;Halls et al, 2015), or very rapid true polar wander (TPW) episodes (Evans, 2003;Kirschvink et al, 2005;McCausland et al, 2007;Mitchell et al, 2011). respect to the rotational axis due to the angular momentum conservation (Munk & MacDonald, 1960). Similar features were suggested for the APWP of Baltica (e.g., Abrajevitch & Van der Voo, 2010).…”

Section: Introductionmentioning

confidence: 99%

True Polar Wander: A Key Indicator for Plate Configuration and Mantle Convection During the Late Neoproterozoic

Robert

Greff-Lefftz

Besse

2018

Geochem Geophys Geosyst

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Large polar motions are observed in the apparent polar wander paths of several continents during the Ediacaran. Among various hypotheses proposed in the literature, one consists of the occurrence of two successive fast and large true polar wander (TPW) episodes, from 615 to 590 Ma and then between 575 and 565 Ma. In this study, we explored the effect of the reactivation of a girdle of subduction to produce such TPW. First, we performed a reconstruction of the main continents between 615 and 520 Ma including Laurentia, Baltica, west and central Gondwana, and Australia‐Antarctica. We then implemented this paleogeography into a simple mantle dynamic model to calculate the TPW during the Ediacaran. Our results show that the reactivation of a girdle of subduction surrounding the continents along with a reduced effect of the return flow rising from the lower mantle can produce two TPW episodes consistent with the paleomagnetic observations. This mechanism is possible if the sinking velocities associated with the girdle of subduction drastically decrease between 635 and 730 Ma. Such a large geodynamic event is consistent with the detrital zircon age distribution of the Neoproterozoic supporting a low subduction activity during the Cryogenian and a boost during the Ediacaran. Decrease of subduction‐related stress induced on the lithosphere may have interrupted the rifting of the supercontinent Rodinia for 100 Ma. Finally, the weakening in subduction magmatism might have strongly reduced the CO2 flux into the atmosphere and played a major role in driving the Neoproterozoic global‐scale glaciations.

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“…Similarly incompatible, shallow and steep, magnetization directions have been observed in Ediacaran rocks at multiple localities in Laurentia, Baltica, and Africa (e.g., Abrajevitch & Van der Voo, ). Although the primary versus secondary nature of these components is disputed (e.g., Bono & Tarduno, ), the primary nature of several components has been demonstrated by paleomagnetic tests in several cases (e.g., Halls et al, ; Robert et al, ). The proposed explanations for such incompatible components range from true polar wander (TPW) (e.g., Evans, ; Robert et al, ), an equatorial dipole (Abrajevitch & Van der Voo, ), or an unusually high number of transitional directions (e.g., Halls et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…Although the primary versus secondary nature of these components is disputed (e.g., Bono & Tarduno, 2015), the primary nature of several components has been demonstrated by paleomagnetic tests in several cases (e.g., Halls et al, 2015;Robert et al, 2017). The proposed explanations for such incompatible components range from true polar wander (TPW) (e.g., Evans, 1998;Robert et al, 2017), an equatorial dipole (Abrajevitch & Van der Voo, 2010), or an unusually high number of transitional directions (e.g., Halls et al, 2015). So far, no deviating components have been reported from Australia.…”

Section: Paleomagnetismmentioning

confidence: 99%

Magnetic Properties and Paleomagnetism of Zebra Rock, Western Australia: Chemical Remanence Acquisition in Hematite Pigment and Ediacaran Geomagnetic Field Behavior

Abrajevitch

Pillans

Roberts

et al. 2018

Geochem Geophys Geosyst

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Zebra Rock, a decorative stone remarkable for its unusual pattern of regularly spaced reddish bands and rods with white background, is found within the Neoproterozoic succession in East Kimberley, Western Australia. The unusual pigment distribution suggests that precipitation of hematite, or its precursor phase, occurred in a single episode. Magnetic properties of hematite pigment in Zebra Rock are distinctly different from those of the host shale, with a smaller median particle size and higher degree of structural perfection. The low thermal stability of the Zebra Rock pigment, with onset of thermal alteration at 300°C, suggests that the rocks have not undergone significant metamorphic heating. Stepwise thermal demagnetization reveals multiple magnetization components. Short‐range variability in the relative contributions of the components to the total remanence is indicative of the stochastic nature of the hematite pigment growth process. In addition to seven magnetization components with shallow to intermediate inclinations that can be matched to the Paleozoic Australian apparent polar wander path, Zebra Rock samples contain a distinct steeply dipping magnetization that is not observed in the host shales. The steep magnetization appears to be primary, based on its unique association with the Zebra pattern, dissimilarity with younger directions, and evidence for low degree of thermal alteration of the rocks. The steep characteristic remanence contrasts with previous paleomagnetic indications of low Australian Neoproterozoic paleolatitudes. The characteristic Zebra Rock magnetization is the first Australian example of incompatible magnetization directions that have been reported previously from Ediacaran rocks in Laurentia, Baltica, and Africa.

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A paleomagnetic and U–Pb geochronology study of the western end of the Grenville dyke swarm: Rapid changes in paleomagnetic field direction at ca. 585Ma related to polarity reversals?

Cited by 60 publications

References 45 publications

Laurentia-Baltica-Amazonia relations during Rodinia assembly

Laurentia-Baltica-Amazonia relations during Rodinia assembly

True Polar Wander: A Key Indicator for Plate Configuration and Mantle Convection During the Late Neoproterozoic

Magnetic Properties and Paleomagnetism of Zebra Rock, Western Australia: Chemical Remanence Acquisition in Hematite Pigment and Ediacaran Geomagnetic Field Behavior

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