TECTONIC AND SEDIMENTARY LINKAGES BETWEEN THE BELT-PURCELL BASIN AND SOUTHWESTERN LAURENTIA AND IMPLICATIONS FOR SUPERCONTINENT CONFIGURATIONS DURING THE MESOPROTEROZOIC, CA. 1.60–1.40 GA
At ca. 1.45 Ga, both the Belt- Purcell and southwest U.S. successions underwent major sedimentological changes, with a pronounced shift to Laurentian provenance and the disappearance of 1.61–1.50 Ga detrital zircon. Upper Belt-Purcell strata contain strongly unimodal ca. 1.73 Ga detrital zircon age populations that match the detrital zircon signature of Paleoproterozoic metasedimentary rocks of the Yavapai Province to the south and southeast. We propose that the shift at ca. 1.45 Ga records the onset of the Picuris Orogeny in southern Laurentia coeval with rifting along its northwestern margin. Bedrock uplift associated with orogenesis and widespread, coeval magmatism caused extensive exhumation and erosion of the Yavapai Province ca. 1.45–1.36 Ga, providing a voluminous and areally extensive sediment source––with suitable zircon ages––during upper Belt deposition. This model provides a comprehensive and integrated view of the Mesoproterozoic tectonic evolution of western Laurentia and its position within the supercontinent Columbia as it evolved into Rodinia.