Unraveling the cryptic Neoproterozoic tectonic evolution of the western margin of Baltica

The Neoproterozoic evolution of the western Baltican margin is fundamental to models of Proterozoic paleogeography and assembly of the North Atlantic region. Conventional interpretations place Baltica and Laurentia facing each other following Sveconorwegian collision at ca. 1000 Ma, with rifting and Iapetus Ocean opening at ca. 600 Ma. However, several recent studies challenge this framework, suggesting that Sveconorwegian Orogeny did not involve continent–continent collision but rather an active-margin system, allowing for substantially different paleogeographic starting conditions for the subsequent Neoproterozoic evolution. Neoproterozoic detrital records from western Baltica indicate relatively proximal active sources and episodic medium- to high-grade metamorphic events in the allochthonous Seve and Kalak nappe complexes imply an accretionary margin setting between ca. 980 and 600 Ma. These observations call for a critical reevaluation of long-standing passive-margin models for the Neoproterozoic western Baltican margin and the timing and nature of Iapetus Ocean opening. Progress relies on moving beyond long-held models and integrating multimineral detrital datasets to generate robust barcodes for sedimentary successions, resolving Neoproterozoic tectonothermal histories for allochthonous units, better-constrained Ediacaran paleolatitudinal control, multidisciplinary studies involving geology and geophysics to verify critical temporal and spatial relationships between different rock units and, importantly, critically testing existing models.