A LATE MESOPROTEROZOIC SEMI-SUPERCONTINENT “LAUSINALIA”

Semi-supercontinent is the hierarchical level attained by Gondwana, Eurasia and similarly large and long-lived landmasses that were subsets of true supercontinents. Based on an idealized supercontinent cycle with two successive stages of assembly, one might expect a semi-supercontinent during the Nuna-Rodinia transition, but whether it existed or not, and its configuration, are still controversial.

Umkondia and WABAMGO were proposed as late Mesoproterozoic semi-supercontinents. Umkondia was originally based on matching only the ca.1100 Ma paleomagnetic data and large igneous provinces (Choudhary et al., 2019), and was later suggested as a megacontinent (synonymous with semi-supercontinent). However, the putative assembly history of Umkondia is not yet well defined. WABAMGO is suggested as a long-lived assemblage forming as early as ca.1260 Ma (Antonio et al., 2021), but this reconstruction would seem at odds with a collisional interpretation of the Putumayo Orogen from Amazonia.

In this study, by compiling the available paleomagnetic data, Laurentia, Siberia, North China craton and the Australian cratons share a similar apparent polar wander path in shape and age during ca. 1140–750 Ma. We propose there should be one late Mesoproterozoic semi-supercontinent “Lausinalia” at late Mesoproterozoic, although large-scale dextral shearing model between the Australian cratons and Laurentia at ca.1050–900 Ma was postulated (Wen et al., 2018).

The Lausinalia hypothesis plays a pivotal role in regulating the rhythm of the supercontinent cycle, determining the spatial patterns of the amalgamation of the supercontinent Rodinia (introversion, extroversion or orthoversion), as well as assessing the global tectonic evolution of Earth’s middle age.

Reference

Antonio et al., 2021, West Africa in Rodinia: High quality paleomagnetic pole from the ~860 Ma Manso dyke swarm (Ghana): Gondwana Research, v. 94, p. 28–43.

Choudhary et al., 2019, Geochemical characterization of a reconstructed 1110 Ma Large Igneous Province: Precambrian Research, v. 332, 105382.

Wen et al., 2018, A positive test for the Greater Tarim Block at the heart of Rodinia: Mega-dextral suturing of supercontinent assembly: Geology, v. 46, p. 687–690.