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A tectonic model for the Transcontinental Arch: Progressive migration of a Laurentian drainage divide during the Neoproterozoic–Cambrian Sauk Transgression

A widespread provenance shift recorded by passive margin strata of western Laurentia, from predominant Stenian (1.2–1.0 Ga) detrital zircon age components to their absence, occurred during the Neoproterozoic–Cambrian Sauk transgression and is commonly used as a ca. 540 Ma chronostratigraphic marker throughout the west/south‐western United States. However, in Neoproterozoic–Cambrian strata of this region, we identify a probable shift from distal to more proximal Stenian‐age zircon sources before a diachronous loss of Stenian detrital zircon age components. We suggest these provenance patterns reflect progressive subsidence of the passive margins surrounding Laurentia and concomitant relative uplift of the Transcontinental Arch, a broad and segmented northeast–southwest trending topographic high across the Laurentian midcontinent possibly due to lithospheric flexure. The Transcontinental Arch segments align with transverse rift structures of the Neoproterozoic–Cambrian Iapetan margin and the Mesoproterozoic Midcontinent Rift, perhaps reflecting rejuvenation of midcontinent lithospheric weaknesses during the Sauk transgression and final Rodinia breakup.