Late Mesoproterozoic rifting in Arctic Canada during Rodinia assembly: impactogens, trans-continental far-field stress and zinc mineralisation

• Published in: Terra nova (Oxford, England) England), 2016-06, Vol.28 (3), p.188-194
• Main Authors: Turner, Elizabeth C., Long, Darrel G. F., Rainbird, Robert H., Petrus, Joseph A., Rayner, Nicole M.
• Format: Article
• Language: English
• Subjects: Geophysics; Mineralization; Plate tectonics; Seismology; Zinc
• ISSN: 0954-4879; 1365-3121
• DOI: 10.1111/ter.12207

This paper challenges the conventional interpretation of a major, economically important Mesoproterozoic intracratonic rift system as a group of aulacogens, proposing instead that they are rifts that developed in response to far‐field stress caused by continent–continent collision (impactogens) during supercontinent assembly. The tectonostratigraphic evolution of the Bylot basins (Arctic Canada) records dramatic alternations between extensional and compressional stress regimes, precluding an aulacogen interpretation and favouring an impactogen interpretation. New geochronological data (U–Th–Pb whole‐rock depositional age; detrital zircon signatures) provide a record of impactogens that developed in Laurentia's interior as a result of Grenvillian (~1.1 Ga) far‐field stress during assembly of the supercontinent Rodinia. Formation of the world‐class Nanisivik zinc deposit in one of the rifts is temporally associated with the Grenvillian orogeny, and consequently represents both (i) a rare exception to the global pattern of few ore deposits forming during supercontinent episodes, and (ii) a hitherto unrecognised tectonic setting for carbonate‐hosted zinc deposits.