and U.S. Army
Earth Science Applications, National Training Center, Fort Irwin

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Applying Geology to Modelling the Past

Rocks and deposits of Fort Irwin range in age from deposited months ago to having formed millions and millions of years ago. By understanding where these deposits formed (dry lakes, alluvial fans, or oases), we can interpret changing geography over time. For instance, playa and spring deposits that once formed in low areas of ponding water are now faulted and pushed up onto some of the highest ridges. Fossils and volcanic ashes in the playa deposits indicate that they are 3.5 million years old. Although it seems like a lot of time to make changes like these, information like this tells a geologist that the area is quite active: faults have been rupturing repeatedly during the last several million years and mountains and valleys we now see are very young features.
Two fly-bys were created to depict the changes in ray-traced landscape created from DEMs. One flies along the modern topography from Goldstone toward the Tiefort Mountains. The route is along a major fault that caused most of this dramatic change in topography. The second flies the same route as it may have looked 3.5 million years ago. We have not developed means for showing these on the web yet, but will as soon as possible. Similar techniques, applied to other areas, can be viewed.

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