Talk:Epeirogenic movement

After c.55Ma, was the central regions of the North American continental crust "uplifted"; or did the oceanic crust, out in the ocean basins, age, cool, and subside (so draining epicontinental seas out into themselves), as earth plate tectonics slowed? According to the Wikipedia article on the Supercontinent Cycle, slower plate movements translate into older oceanic plates, which lie lower beneath continental surfaces, so deepening ocean basins, and draining away inland seas. This article confuses me -- was the draining away of the Western Interior Seaway due to continents rising, or ocean basins sinking? Perhaps the article could be improved, and clarify that concept. 66.235.38.214 (talk) 12:56, 1 November 2012 (UTC)