Ashfall Fossil Beds, Nebraska

Ashfall Fossil Beds, Late May 2013

On our way to attend a gathering of fiberglass camping trailers we stopped at the Ashfall Fossil Beds State Historical Park in rural northeastern Nebraska. It takes a little doing to get to this place; it is certainly not on the way to anywhere else. But, if you have any interest in the geologic and paleologic history of North America, these fossil beds should be on your "must see" list. They are, in fact, unique in all the world!

Arriving at the park, your first stop is the visitor center where you pay the entry fee. Considering the costs of other attractions around the country, the entry fee to the fossil beds is quite modest. Be sure to allow plenty of time when you visit the park. To more fully understand what you will see later on, you should study the many artifacts and informative displays in the visitor center.

The Ashfall Fossil Beds Visitor Center

 The displays and artifacts in the visitor center are very well done. They are very approachable and easy to understand yet manage to convey a ton of information about a sequence of events that happened at the site some twelve million years ago.

Inside the visitor center

 The fossil beds themselves are located a short walk from the visitor center. They are protected by a large structure built on the side of the gully where the fossils were discovered. To give you a sense of how long ago the events that created the fossil beds occurred, each step you take on the walk takes you 30,000 years back in time.

Walking 12,000,000 years back in time

These fossil beds are an active paleontology site. From May through September, university students from around the country work to uncover more of the fossils. A unique feature of this place is that any fossil that is uncovered from the ash bed is left in place. Enough of the ash is removed to reveal the entire fossil, and there it is, just as it was when the animal died all those millions of years ago!

The majority of the fossils uncovered thus far are of barrel-bodied rhinoceros, an ancient species now extinct. Along with the rhinos, there are fossils of several species of dog, of three-toed horses, and even of birds, lizards, and turtles. All of this is in the Hubbard Rhino Barn, as the large building covering the beds is called.

Inside the Hubbard Rhino Barn

In the rhino barn, a series of trenches twenty feet apart have been dug to determine the extent of the fossils in the ash bed. Nancy and I were the only people in barn. As we walked along, studying the fossils and the displays along the walls, an older gentleman who had been clearing dirt from one of the trenches returned to the barn to continue working.  He stopped to ask if we had any questions.

We had a few and we asked them. He seemed to know quite a lot about the fossils, so we asked more questions, many, many more questions. What we got from him was a veritable seminar on the animals whose fossils are in the beds, how they came to be there, why the fossils are so remarkably well preserved, and on and on... It was fascinating.

Turns out, the older gentleman was Dr. Mike Voorhies. Dr. Voorhies is an emeritus professor of paleontology at the University of Nebraska, Lincoln. He was the person who made the initial discovery at the Ashfall site. He is THE expert on the Ashfall site! What a fortuitous encounter!

Nancy talking with Dr. Voorhies about some of the fossils

 The animals in the fossil beds died from suffocation when very fine ash (actually, finely powdered glass) from a volcano far to the west covered the region to a depth of one or two feet.

(1) Barrel-bodied rhino, (2) Three-toed horse

Barrel-bodied rhino bull

 The volcano that produced the ash that covered Nebraska resulting in the deaths of the animals in the fossil beds was located in what is now southwestern Idaho. It was one of a series of volcanoes that erupted as the tectonic plate of North America moved to the west and south over a hot spot in the Earth's mantle. The most recent eruption in this series is the super-volcano that created the caldera that now holds Yellowstone National Park.

A map of the ash plume

As I mentioned at the beginning, Ashfall Fossil Beds State Historical Park, deserves a spot on your "Must See" list. Although may be a bit off the beaten track, it is very much worth the effort to get to.

Some useful links:
About the Ashfall Fossil Beds State Historical Park
http://ashfall.unl.edu/

About Dr. Voorhies's discovery of the fossil beds:
http://nebraskastudies.org/0200/stories/0201_0103.html

About Dr. Voorhies:
http://www.geosciences.unl.edu/people/faculty_page.php?lastname=Voorhies&firstname=Michael&type=ADJ