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Implications of Paleogeologic Maps of North America: Abstract
A sequence of subcrop and paleogeologic maps of North America are presented showing the geology at the beginning of the Ordovician, Devonian, Mississippian, Pennsylvanian and Cretaceous systems.
There are many implications to be seen in such a set of maps. Some are as follows:
1. The continent has been in repeated periods of broad structural upswells in which great arches formed. Later the crests were eroded, the surface peneplaned, and the overlying sediments deposited across the truncated edges of the older rocks.
2. The intervening basins are structural and not depositional in nature. Their location is fortuitous, inasmuch as the boundaries are formed by arches that occurred at different times.
3. Each time an arch or regional uplift occurs, the pressures and temperatures within the sediments change, volumes change, and as the pressures and temperatures return to equilibrium, the fluids move to adjust to the changing conditions. This is the time of oil and gas migration, and local traps present at the time of migration become the sites of oil and gas pools. Hydrodynamic phenomena are set up and the flow of all fluids is influenced by these uplifts. Either barren or productive regions may be due to these changes in fluid flow and fluid pressure.
4. The location of favorable rock and fluid regions is greatly helped by the preparation of paleogeologic maps and thus becomes a powerful exploration tool.
Acknowledgments and Associated Footnotes
1 Consulting Geologist
Copyright © 2006 by the Tulsa Geological Society