Early in the Decade of North American Geology, a planning document was assembled and published as Perspectives in Regional Geological Synthesis (Palmer, 1982). This collage of diverse contributions included an item devoted to the North American Craton in the United States that closed with several “unresolved questions” (Sloss, 1982a, p. 39):

What is the significance of episodic emergences of the craton responsible for the sequence-bounding unconformities? The natural corollary is the meaning of the several episodes of cratonic submergence. In both cases the magnitude of vertical movement far exceeds that which could be ascribed to any combination of eustatics and loading-unloading by sediment and water. Is there a demonstrable correlation with plate interactions?

Why is deformation of the craton sometimes dominated by flexure, at other times by fracture? When the fractural mode is operating, is the continental crust in extension or compression? That is, are the downdropped basins and block uplifts characteristic of Absaroka I deposition produced by thrusts of Wind River type or are they representative of distinctly different stress/strain patterns? In either case, what are the driving forces?

Is the tectonic mode prevailing on the craton during Sauk deposition as distinct from the younger Phanerozoic as is suggested here? If so, does this indicate that there are irreversible secular changes in cratonic behavior as a product of evolving crustal thickness, or rheologic change, or whatever?

Why do sedimentary basins and intervening arches remain fixed in positions for hundreds of millions of years? Is it demonstrable that basins are