Figure 3

Figure 3.

(A) Schematic reconstruction of plate positions relative to Laurentia ca. 1100 Ma during formation of Rodinia. After the Elzeverian and Shawinigan orogenies, but before the Grenville orogeny, spreading likely initiated between the major plates. Following failure of the Midcontinent Rift (MCR), Amazonia shifted north along the margin before recolliding. (B) Similar reconstruction at ca. 560 Ma as Rodinia was breaking up. Cuyania (Cu) block rifted off Laurentia, leaving the Southern Oklahoma Aulacogen (SOA) and Reelfoot Rift (RR) as failed arms. (C) Apparent polar wander (APW) path of Laurentia, plotted in present-day coordinates, at 10-m.y. increments. Red cusp (1200–1000 Ma) is related to formation of the MCR, and blue cusp (700–500 Ma) is related to initial rifting of the SOA and RR. Path between these events plotted in gray.

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