A dynamic 2000—540 Ma Earth history: From cratonic amalgamation to the age of supercontinent cycle

Emplacement of the Argyle diamond deposit into an ancient rift zone triggered by supercontinent breakup

“…The same applies to Argyle and Nuna breakup. Whilst Argyle appears to be coincident with the onset of Nuna breakup, together with temporally near-coincident magmatism at Helpmekaar in South Africa 41 and kimberlites in the East European platform 43 , it is not until 1200-1100 Ma that diatreme emplacement peaked worldwide, coincident with accelerated plate velocities 30 . Thus, there appears to be a first-order control of continental extension and plate velocities on (diamondiferous) kimberlite and related volatile-rich ultramafic diatreme production 41 .…”

“…At the time, most plate tectonic reconstructions place Argyle at the periphery of the McArthur-Yanliao Gulf (Fig. 4), an intercontinental Mesoproterozoic basin between proto-Australia, North China, Siberia and Laurentia [27][28][29][30][31][32] (and in some reconstructions also including India 29,31 and/or South China 28,29 ). Temporally-constrained paleomagnetic and geological evidence indicates that Nuna was together at c. 1320 but dispersed by c. 1220 Ma, with scarce high-quality paleomagnetic data in the intervening 100 Myr making it difficult to be more precise on the exact timing of breakup 28 .…”

“…Continental amalgamation and associated post-orogenic relaxation/extension is known to be better at preserving the geological record 47,48 . Thus, one might expect that preservation would be higher at c. 1800-1600 Ma (Nuna assembly), 1100-900 Ma (Rodinia assembly), 650-500 Ma (Gondwana assembly) and 250-200 Ma (Pangea assembly) 30 . With the exception of Gondwana assembly, periods of continental breakup after supercontinent assembly are marked by significantly more kimberlite and related volatile-rich ultramafic production 38,49 , further supporting the notion that crustal extension is a first order control that is not erased by preservation bias.…”

“…The implication is that continental extension is one of the dominant driving forces in ensuring that volatiles are destabilised in the deep mantle and propagated towards the surface. That being said, there was still likely significant erosion of breakup-related diatremes, and it is perhaps for this reason that 30 . The potential extent of plume head that caused the Derim Derim-Galiwinku-Yanliao LIP is also shown, with its dimension elongated along rift zones 28,34 .…”

On pole position

“…Prior to the Jurassic, paleomagnetism provides the main quantitative tool to reconstruct paleogeography and to estimate 'absolute' plate tectonic motions (Torsvik et al, 2008a;Domeier & Torsvik, 2014). Paleomagnetic data has played a key role in deciphering paleogeography in deep geological time and forms the foundation of most Precambrian plate reconstructions (Piper, 1974;Merdith et al, 2017Merdith et al, , 2021Li et al, 2023), providing quantitative constraints on the past existence and configuration of supercontinents, such as Rodinia, Nuna and other -more speculative -continents like Kenorland (Evans, 2013), as well as on the onset of plate tectonics in deep geological time (e.g., Evans & Pisarevsky, 2008;Brenner et al, 2020;. In addition to these deeptime applications, paleomagnetic data also has many applications for the reconstruction of relative motions of tectonic terranes through time (Beck, 1976;Demarest, 1983;Butler, 1992): allowing the estimation of vertical-axis rotations, relative convergence, and the paleolatitudinal evolution of intra-oceanic terranes.…”