Places to See Cretaceous Rocks in Nebraska
Cretaceous rocks are found on the eastern side of Nebraska. The map below shows three good locations to see Cretaceous-age rocks in Nebraska. Each of the three parks is briefly described in further detail below the map. To learn more about the different Cretaceous rocks of Nebraska, click HERE.
Niobrara State Park
Niobrara State Park is located in northern Nebraska along the border with South Dakota. At this park, excellent exposures of the Niobrara Formation can be observed on the trails along the river. Near the entrance of the park, thick exposures of dark gray/black Pierre Shale can be seen. There are several yellow/white volcanic ash (bentonite) layers within the shale. In some locations along the river, the Crow Creek Member of the Pierre Shale (bright white and ~10 feet thick) can be seen. This layer formed from an ancient tsunami, which occurred after a large asteroid struck Iowa 74 million years ago. Click HERE to learn more about the Manson Impact Crater in Iowa. Also known from the park are large Mosasaur skeletons, which were giant marine reptiles.
For more information about visiting Niobrara State Park, Click HERE.
Ponca State Park
Ponca State Park is another good location to see Cretaceous rocks in Nebraska. At this park, you can see some of the older Cretaceous units in Nebraska, including the Graneros Shale, Greenhorn Limestone, and Dakota Formation. Near the boat ramp in the park, there are ~150 feet of Graneros Shale and Greenhorn Limestone exposed along a cliff. You can see yellow/white ash (bentonite) layers within the Graneros Shale portion of the outcrop. Further downstream of the boat ramp, exposures of the Dakota Formation can be observed.
For more information about visiting Ponca State Park, Click HERE.
Rock Creek Station
Rock Creek Station State Historical Park is a good location to observe exposures of the Dakota Formation, which is the oldest Cretaceous unit preserved in Nebraska. There is one good exposure of sandstone within the park, located along the river. If you travel along nearby State Highway 15 (south of Fairbury, NE) towards Kansas, you will see several exposures of Dakota Formation (mostly sandstone and reddish shale). Closer to Kansas along Highway 15, an exposure of dark gray/black Graneros Shale can be observed along the eastern side of the road.
For more information about visiting Rock Creek Station, Click HERE.
For more information about geology locations in Nebraska (from many geological time periods), see Maher, H., Engelmann, G., and Shuster, R., (2003), Roadside Geology of Nebraska, Mountain Press Publishing Company, 264p.