Overthrust Fault

Located near the National Zoo in Washington, D.C., is a fenced-in area that looks like nothing more than a giant pile of dirt and rocks. However, it's much more than that, it's actually an amazing example of an overthrust fault. This type of fault occurs when the upper side of the fault is pushed up through constant compression. There are actually several various examples of overthrust faults found around the nation's capital.

The layers of rock represent the Piedmont region and the Atlantic Coastal Plain. Geologists were surprised to discover these faults as it was believed that the region wasn't a geological hotspot. Geologist N.H. Darton first discovered the overthrust during the 1920s and had the fault enclosed and protected from the elements. However, erosion still weathered down the fault making it difficult to view today.