2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 8
Presentation Time: 10:15 AM

Advancing and Quantifying Paleogeographic Maps


UMHOEFER, Paul J. and BLAKEY, Ronald C., Geology, Northern Arizona University, Box 4099, Flagstaff, AZ 86011, paul.umhoefer@nau.edu

In recent years, the tectonics community has realized the critical need to better understand the complete paleogeographic evolution of an ancient orogen – its 4D history. As the importance of the role of tectonics and climate and their feedback is increasing, it is clear that the history of the landscape of a region is a key to understanding long-term tectonic processes. Current paleogeographic maps are being used extensively for teaching, in the oil & gas industry, and in some research applications. But their use as major research tools that fully integrate diverse datasets is less apparent; however, paleogeographic maps have great potential for tectonics research. An accompanying presentation uses traditional maps of west-central North America in the Cretaceous to investigate plate boundary and interior events. We target five diverse basins: Bisbee AZ, Kaparowits UT, Great Valley CA, Ochoa OR, Tyaughton-Methow BC-WA. How can we make progress in quantifying paleogeographic maps? One advancement will be making fully digital maps in ArcGIS so that metadata and other tools can elucidate the legacy of how the map was made and integrate them with fast-growing data archives. Another promising approach is to incorporate a “source to sink” view of specific regions at specific time intervals. Because maps are holistic, a source to sink view is natural. For the five basins, we look at diverse data sets during early Early (140 Ma), late Early (100 Ma), and Latest (70 Ma) Cretaceous: we plot igneous activity and exhumation in source areas, facies and isopach patterns, paleocurrents of fluvial systems, deltas and shorelines, offshore sandstone packages. Examining these criteria for each age-specific source-to-sink system readily reveals both data gaps and links across an orogen and targets future research.