A tectonic-rules-based mantle reference frame since 1 billion years ago – implications for supercontinent cycles and plate–mantle system evolution

Abstract

Abstract. Understanding the long-term evolution of Earth's plate–mantle system is reliant on absolute plate motion models in a mantle reference frame, but such models are both difficult to construct and controversial. We present a tectonic-rules-based optimization approach to construct a plate motion model in a mantle reference frame covering the last billion years and use it as a constraint for mantle flow models. Our plate motion model results in net lithospheric rotation consistently below 0.25∘ Myr−1, in agreement with mantle flow models, while trench motions are confined to a relatively narrow range of −2 to +2 cm yr−1 since 320 Ma, during Pangea stability and dispersal. In contrast, the period from 600 to 320 Ma, nicknamed the “zippy tricentenary” here, displays twice the trench motion scatter compared to more recent times, reflecting a predominance of short and highly mobile subduction zones. Our model supports an orthoversion evolution from Rodinia to Pangea with Pangea offset approximately 90∘ eastwards relative to Rodinia – this is the opposite sense of motion compared to a previous orthoversion hypothesis based on paleomagnetic data. In our coupled plate–mantle model a broad network of basal mantle ridges forms between 1000 and 600 Ma, reflecting widely distributed subduction zones. Between 600 and 500 Ma a short-lived degree-2 basal mantle structure forms in response to a band of subduction zones confined to low latitudes, generating extensive antipodal lower mantle upwellings centred at the poles. Subsequently, the northern basal structure migrates southward and evolves into a Pacific-centred upwelling, while the southern structure is dissected by subducting slabs, disintegrating into a network of ridges between 500 and 400 Ma. From 400 to 200 Ma, a stable Pacific-centred degree-1 convective planform emerges. It lacks an antipodal counterpart due to the closure of the Iapetus and Rheic oceans between Laurussia and Gondwana as well as due to coeval subduction between Baltica and Laurentia and around Siberia, populating the mantle with slabs until 320 Ma when Pangea is assembled. A basal degree-2 structure forms subsequent to Pangea breakup, after the influence of previously subducted slabs in the African hemisphere on the lowermost mantle structure has faded away. This succession of mantle states is distinct from previously proposed mantle convection models. We show that the history of plume-related volcanism is consistent with deep plumes associated with evolving basal mantle structures. This Solid Earth Evolution Model for the last 1000 million years (SEEM1000) forms the foundation for a multitude of spatio-temporal data analysis approaches.

Ghost-arc geochemical anomaly at a spreading ridge caused by supersized flat subduction

“…3 a, b), the extreme inland growth of the South Gondwana flat slab would not have been caused by forced trench retreat as documented in active flat subduction in the Andes 45 . Thus, this process most likely resulted from large-scale inland migration of the flat slab tip at different possible rates that, depending on the mantle reference frame used, are 6 cm/yr 32 , 5.42 cm/yr 33 , and 5.08 cm/yr 34 (Fig. 4 , Methods).…”

“…The inland growth of the South Gondwana flat slab would have taken place with different possible magnitudes depending on the mantle reference frame employed. The reconstructions yield variable but large paleo-trench-slab distances (2600 km 32 , 2400 km 33 , and 2280 km 34 ) (Figs. 3 d, 4 , Supplementary Fig.…”

“…This model includes a recently developed approach 62 to reconstruct absolute plate motions back to 220 Myr ago in a mantle reference frame using a joint global inversion of multiple constraints, including hot spot location and associated trail data for the last 80 Myr, optimization of subduction zone migration behaviour considering global trench migration, and estimates of net lithospheric rotation, providing both paleo-latitudes and paleo-longitudes relative to the mantle. Also, we included Mesozoic plate kinematic reconstructions utilizing the mantle reference frames of Müller et al 33 , van der Meer et al 34 and Torsvik and Cocks 35 (Supplementary Fig. 3) .…”

“…3) . Müller et al 33 extend the concept of ‘tectonic rules-based mantle reference frame’ introduced by Tetley et al 62 by including the evaluation of continental velocities relative to the mantle as an additional criterion. The model of van der Meer et al 34 is built on the paleomagnetic frame of Torsvik et al 63 and constraints paleolongitude based on tomographic images of subducting slabs distributed in the mantle.…”

Quantifying the Link Between the Detrital Zircon Record and Tectonic Settings

“…We focus primarily on the utility of detrital zircon samples to make the first-order discrimination between areas witnessing active subduction or not. Robustly mapping these areas (and assessing confidence in these maps) is particularly important for many applications of full-plate models, such as applying boundary conditions for simulations of mantle flow (e.g., Flament, 2019) and estimating long-term changes in volatile fluxes at subduction zones (e.g., Mills et al, 2017;Müller et al, 2022). As well as for subduction zones, we also consider how the characteristics of detrital zircon spectra depend on the proximity to continental rifts, both active and passive and failed and successful.…”