Precise U–Pb baddeleyite dating of the Derim Derim Dolerite, McArthur Basin, Northern Territory: old and new SHRIMP and ID-TIMS constraints

Bodorkos, S.; Crowley, James L.; Claoué-Long, Jonathan C.; Anderson, J.R.; Magee, C. W.

doi:10.1080/08120099.2020.1749929

Cited by 18 publications

(25 citation statements)

References 31 publications

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“…3) suggests fluid-rock interaction processes involving substantial influx of radiogenic crustal fluids during the purported potassic alteration of the dolerite. The Rb-Sr age obtained from sample UR5_229 dolerite overlaps, within error, the crystallization ages of Derim Derim intrusions obtained elsewhere in the McArthur Basin (Bodorkos et al, 2020;Yang et al, 2020), indicating that this fluid-infiltration event likely happened during or soon after dike intrusion.…”

Section: Discussionsupporting

confidence: 60%

Unraveling the histories of Proterozoic shales through in situ Rb-Sr dating and trace element laser ablation analysis

Subarkah

Blades

Collins

et al. 2022

Geology

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Authigenic components in marine sediments are important archives for past environment reconstructions. However, defining reliable age constraints and assessing the effects of post-depositional overprints in Precambrian sequences are challenging. We demonstrate a new laser-based analytical approach that has the potential to rapidly and accurately evaluate the depositional and alteration histories of Proterozoic shales. Our study employs a novel application of in situ Rb-Sr dating coupled with simultaneous trace-element analysis using reaction-cell laser ablation–inductively coupled plasma–tandem mass spectrometry (LA-ICPMS/MS). We present results from shales sourced from two wells in the Proterozoic McArthur Basin, northern Australia. These rocks have been widely used by previous studies as a key section for ancient biogeochemical and paleo-redox reconstructions. Shales from well UR5 yielded initial 87Sr/86Sr ratios, Rb-Sr ages, and rare earth element plus yttrium (REEY) patterns similar to those of a dolerite sampled from the same core. We propose that the UR5 samples chronicle hydrothermal alteration instigated by the dolerite intrusion. In contrast, a correlative shale from well UR6 yielded an age consistent with the expected depositional age (1577 ± 56 Ma) with REEY and initial 87Sr/86Sr ratios similar to ca. 1.5 Ga seawater. We suggest that this sample records the minimum depositional age and early marine diagenetic history for this unit. This new technique can date Proterozoic shales quickly, cheaply, and with minimum sample preparation. Importantly, ages are triaged to differentiate between those recording primary marine versus secondary processes. This novel approach provides a potentially powerful tool for dating and fingerprinting the vast array of ancient marine shales for further studies of Earth systems through deep time.

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Section: Discussionsupporting

confidence: 60%

Unraveling the histories of Proterozoic shales through in situ Rb-Sr dating and trace element laser ablation analysis

Subarkah

Blades

Collins

et al. 2022

Geology

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“…Potential rock-based markers for the Calymmian-Ectasian boundary are elusive. Regional-scale, magmatic events such as the c. 1.32 and 1.23 Ga dike/sill swarms of North China (Zhai et al, 2015;Peng et al, 2015;Wang et al, 2016;Zhang et al, 2017), the 1.32 Ga swarm of northern Australia (Yang et al 2020;Bodorkos et al 2021), the c. 1.27 Ga Mackenzie dyke swarm in Canada and the c. 1.12-1.08 Ga Ghanzi-Chobe-Umkondo and Midcontinent Rift systems have not been linked to any global-scale isotopic excursions that could be used for correlation. However, the coincidence of widespread c. 1385 Ma LIPs and black shales has been proposed as a potential rock-based marker for the Calymmian-Ectasian boundary .…”

Section: Mesoproterozoic Era (C 18 To 10 Ga)mentioning

confidence: 99%

A template for an improved rock-based subdivision of the pre-Cryogenian timescale

Shields

Strachan

Porter

et al. 2021

JGS

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The geological time scale before 720 Ma uses rounded absolute ages rather than specific events recorded in rocks to subdivide time. This has led increasingly to mismatches between subdivisions and the features for which they were named. Here we review the formal processes that led to the current time scale, outline rock-based concepts that could be used to subdivide pre-Cryogenian time and propose revisions. An appraisal of the Precambrian rock record confirms that purely chronostratigraphic subdivision would require only modest deviation from current chronometric boundaries, removal of which could be expedited by establishing event-based concepts and provisional, approximate ages for eon-, era- and period-level subdivisions. Our review leads to the following conclusions: 1) the current informal four-fold Archean subdivision should be simplified to a tripartite scheme, pending more detailed analysis, and 2) an improved rock-based Proterozoic Eon might comprise a Paleoproterozoic Era with three periods (early Paleoproterozoic or Skourian, Rhyacian, Orosirian), Mesoproterozoic Era with four periods (Statherian, Calymmian, Ectasian, Stenian) and a Neoproterozoic Era with four periods (pre-Tonian or Kleisian, Tonian, Cryogenian and Ediacaran). These proposals stem from a wide community and could be used to guide future development of the pre-Cryogenian timescale by international bodies.

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“…North China and northern Australia share a similar Mesoproterozoic and early Tonian sedimentary record and both preserve contemporaneous ca. 1.33-1.31 Ga magmatism (Bodorkos et al, 2020;Yang et al, 2020;Zhang et al, 2017) that is interpreted as a large igneous province. Yang et al (2019) also demonstrated the similarity in detrital zircon ages and hafnium isotope compositions between the Tonian strata of both areas.…”

Section: Australia North China Lhasa and Tasmaniamentioning

confidence: 98%

Extending full-plate tectonic models into deep time: Linking the Neoproterozoic and the Phanerozoic

Merdith¹,

Williams²,

Collins³

et al. 2022

Preprint

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Recent progress in plate tectonic reconstructions has seen models move beyond the classical idea of continental drift by attempting to reconstruct the full evolving configuration of tectonic plates and plate boundaries. A particular problem for the Neoproterozoic and Cambrian is that many existing interpretations of geological and palaeomagnetic data have remained disconnected from younger, better-constrained periods in Earth history. An important test of deep time reconstructions is therefore to demonstrate the continuous kinematic viability of tectonic motions across multiple supercontinent cycles. We present, for the first time, a continuous full-plate model spanning 1 Ga to the present-day, that includes a revised and improved model for the Neoproterozoic-Cambrian (1000-520 Ma) that connects with models of the Phanerozoic, thereby opening up pre-Gondwana times for quantitative analysis and further regional refinements. In this contribution, we first summarise methodological approaches to full-plate modelling and review the existing full-plate models in order to select appropriate models that produce a single continuous model. Our model is presented in a palaeomagnetic reference frame, with a newly-derived apparent polar wander path for Gondwana from 540 to 320 Ma, and a global apparent polar wander path from 320 to 0 Ma. We stress, though while we have used palaeomagnetic data when available, the model is also geologically constrained, based on preserved data from past-plate boundaries. This study is intended as a first step in the direction of a detailed and self-consistent tectonic reconstruction for the last billion years of Earth history, and our model files are released to facilitate community development.

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Precise U–Pb baddeleyite dating of the Derim Derim Dolerite, McArthur Basin, Northern Territory: old and new SHRIMP and ID-TIMS constraints

Cited by 18 publications

References 31 publications

Unraveling the histories of Proterozoic shales through in situ Rb-Sr dating and trace element laser ablation analysis

Unraveling the histories of Proterozoic shales through in situ Rb-Sr dating and trace element laser ablation analysis

A template for an improved rock-based subdivision of the pre-Cryogenian timescale

Extending full-plate tectonic models into deep time: Linking the Neoproterozoic and the Phanerozoic

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