Was the Midcontinent Rift part of a successful seafloor-spreading episode?

Carol A. Stein*, Seth Stein, Miguel Merino, G. Randy Keller, Lucy M. Flesch, Donna M. Jurdy

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

The ~1.1 Ga Midcontinent Rift (MCR), the 3000 km long largely buried feature causing the largest gravity and magnetic anomaly within the North American craton, is traditionally considered a failed rift formed by isolated midplate volcanism and extension. We propose instead that the MCR formed as part of the rifting of Amazonia (Precambrian northeast South America) from Laurentia (Precambrian North America) and became inactive once seafloor spreading was established. A cusp in Laurentia's apparent polar wander path near the onset of MCR volcanism, recorded by the MCR's volcanic rocks, likely reflects the rifting. This scenario is suggested by analogy with younger rifts elsewhere and consistent with the MCR's extension to northwest Alabama along the East Continent Gravity High, southern Appalachian rocks having Amazonian affinities, and recent identification of contemporaneous large igneous provinces in Amazonia. Key Points ~1.1Ga Mid-Continent Rift (MCR) formed during rifting of Amazonia from Laurentia MCR continues to northwest Alabama along East Continent Gravity High Apparent polar wander path's cusp reflects rifting event

Original languageEnglish (US)
Pages (from-to)1465-1470
Number of pages6
JournalGeophysical Research Letters
Volume41
Issue number5
DOIs
StatePublished - Mar 16 2014

Keywords

  • Amazonia
  • Laurentia
  • Mid-Continent rift
  • apparent polar wander path
  • continental extension

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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