One of the most important concepts resulting from oceanographic data is the segmented nature of the oceanic ridge and rise areas. These segments are separated by transverse faults. Continental orogenic areas both past and present possibly may exhibit this same phenomenon.

Model studies using vertical uplift were conducted in an effort to duplicate the segments. The forces involved in the development of the individual segments were analyzed, as well as those caused by the interaction between segments resulting from differential uplift. By applying principles observed in the modeling, known first-order orogenic areas were modeled. These areas include parts of the Rocky Mountain system and the California system.

A theory is developed which mechanically relates the orogenic events of the past with those of the present. A proposed corollary relates the major transgressions and regressions of past geologic seas to the geographic distribution of the orogenic belts. During times of extensive oceanic orogenic activity, the belts were distended and the water was displaced onto the continents. The distention was followed by extrusion and collapse which resulted in regression of the seas.

The theory is applied to the continental United States, and a series of sketches shows the possible tectonic development of the southern part of the North American continent from the late Precambrian to the present.

End_of_Article - Last_Page 638------------