A full-plate global reconstruction of the Neoproterozoic

Merdith, Andrew; Collins, Alan S.; Williams, S.; Pisarevsky, Sergei A.; Foden, John; Archibald, Donnelly B.; Blades, Morgan; Alessio, Brandon L.; Armistead, Sheree; Plavsa, Diana; Clark, Chris; Müller, R. Dietmar

doi:10.1016/j.gr.2017.04.001

Cited by 496 publications

(236 citation statements)

References 550 publications

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“…Despite these potential sources, inheritance of c . 2,500–2,400 Ma is lacking in granulites from the northern EGP (Bose, Das, Torimoto, Arima, & Dunkley, ), a region that is in close proximity to the Rengali Orogen (Bhattacharya et al., ; Sawant, Gupta, Clark, & Misra, ), and potentially accessible from the Vestfold, Ruker and Lambert Terranes based on recent Proterozoic plate tectonic reconstructions (Merdith et al., ). However, the Archean Napier Complex records a high volume of anatectic zircon growth in the age range c .…”

Section: Discussionmentioning

confidence: 99%

Neoproterozoic evolution and Cambrian reworking of ultrahigh temperature granulites in the Eastern Ghats Province, India

Mitchell

Johnson

Clark

et al. 2018

Journal Metamorphic Geology

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The time‐scales and P–T conditions recorded by granulite facies metamorphic rocks permit inferences about the geodynamic regime in which they formed. Two compositionally heterogeneous cordierite–spinel‐bearing granulites from Vizianagaram, Eastern Ghats Province (EGP), India, were investigated to provide P–T–time constraints using petrography, phase equilibrium modelling, U–Pb geochronology, the rare earth element composition of zircon and monazite, and Ti‐in‐zircon thermometry. These ultrahigh temperature (UHT) granulites preserve discrete compositional layering in which different inferred peak assemblages are developed, including layers bearing garnet–sillimanite–spinel, and others bearing orthopyroxene–sillimanite–spinel. These mineral associations cannot be reproduced by phase equilibrium modelling of whole‐rock compositions, indicating that the samples became domainal on a scale less than that of a thin section, even at UHT conditions. Calculation of the P–T stability fields for six compositional domains within which the main rock‐forming minerals are considered to have attained equilibrium suggests peak metamorphic conditions of ~6.8–8.3 kbar at ~1,000°C. In most of these domains, the subsequent evolution resulted in the growth of cordierite and final crystallization of melt at an elevated (residual) H2O‐undersaturated solidus, consistent with <1 kbar of decompression. Concordant U–Pb ages obtained by SHRIMP from zircon (spread 1,050–800 Ma) and monazite (spread 950–800 Ma) demonstrate that crystallization of these minerals occurred during an interval of c. 250 Ma. By combining LA‐ICP‐MS U–Pb zircon ages with Ti‐in‐zircon temperatures from the same analysis sites, we show that the crust may have remained above 900°C for a minimum of c. 120 Ma between c. 1,000 and c. 880 Ma. Overall, the results suggest that, in the interval 1,050 to 800 Ma, the evolution of the Vizianagaram granulites culminated with UHT conditions from c. 1,000 Ma to c. 880 Ma, associated with minor decompression, before further zircon crystallization at c. 880–800 Ma during cooling to the solidus. However, these rocks are adjacent to the Paderu–Anantagiri–Salur crustal block to the NW that experienced counterclockwise P–T–t paths, and records similar UHT peak metamorphic conditions (7–8 kbar, ~950°C) followed by near‐isobaric cooling, and has a similar chronology during the Neoproterozoic. The limited decompression inferred at Vizianagaram may be explained by partial exhumation due to thrusting of this crustal block over the adjacent Paderu–Anantagiri–Salur crustal block. The residual granulites in both blocks have high concentrations of heat‐producing elements and likely remained hot at mid‐crustal depths throughout a period of relative tectonic quiescence in the interval 800–550 Ma. During the Cambrian Period, the EGP was located in the hinterland of the Denman–Pinjarra–Prydz orogen. A later concordant population of zircon dated at 511 ± 6 Ma records crystallization at temperatures of ~810°C. This age may record a low‐degree of...

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Section: Discussionmentioning

confidence: 99%

Neoproterozoic evolution and Cambrian reworking of ultrahigh temperature granulites in the Eastern Ghats Province, India

Mitchell

Johnson

Clark

et al. 2018

Journal Metamorphic Geology

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“…Therefore, a stoppage or drastic slowdown of the girdle of subduction could prevent the breakup of Rodinia. The reconstruction and rifting history of Rodinia are still debated, and various configurations were proposed in the literature (Hoffman, 1991;Li et al, 2008;Meert & Torsvik, 2003;Merdith et al, 2017). The reconstruction and rifting history of Rodinia are still debated, and various configurations were proposed in the literature (Hoffman, 1991;Li et al, 2008;Meert & Torsvik, 2003;Merdith et al, 2017).…”

Section: A Correlation Between Phases Of Subduction and Breakupmentioning

confidence: 99%

“…Ediacaran paleogeographic reconstructions rotated in our Laurentia-fixed mantle reference frame between 635 and 575 Ma (a) and between 575 and 520 Ma (b). The relative position of Siberia (S) and north China (NC) compared to Laurentia was inferred using the reconstruction ofMerdith et al (2017). The position of the blocks in gray is controversial.…”

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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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“…Such a scenario is proposed by Meredith et al. () on the basis of geological and palaeomagnetic synthesis. Rodinia moving to low latitude is easily explained as caused by the transition.…”

Section: Could the Transition To Plate Tectonics Have Caused Neoprotementioning

confidence: 99%

Did the transition to plate tectonics cause Neoproterozoic Snowball Earth?

Stern

Miller

2018

Terra Nova

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A full-plate global reconstruction of the Neoproterozoic

Cited by 496 publications

References 550 publications

Neoproterozoic evolution and Cambrian reworking of ultrahigh temperature granulites in the Eastern Ghats Province, India

Neoproterozoic evolution and Cambrian reworking of ultrahigh temperature granulites in the Eastern Ghats Province, India

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

Did the transition to plate tectonics cause Neoproterozoic Snowball Earth?

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