New Exhibit at Berlin-Ichthyosaur State Park

(Winter 1993)

The Nevada Bureau of Mines and Geology contributed chemical analyses of a fossilized ichthyosaur rib bone to a team investigation of this fossil, which resulted in a new educational exhibit at Berlin- Ichthyosaur State Park. The park, which is located 21 miles east of Gabbs, Nevada is a triple attraction for tourists and Nevada residents; it contains the well-preserved mining ghost town of Berlin, a partially excavated digging containing a death assemblage of nine ichthyosaurs, and a campground.

As many readers may know, ichthyosaurs were large sea-going reptiles which roamed the oceans about 225 million years ago (age of the species found at this park). The park contains the most complete and best preserved ichthyosaurs in North America. It also contains the largest examples of these creatures known in the world. The largest one at this locality is perhaps 35 feet long, but it was from a study of these particular fossils that an extrapolation was made that this species probably grew as large as 50 feet.

The research study that resulted in the exhibit was initiated by Schurer & Fuchs, Reno microscopy consultants, who performed photomicrography and mineralogical analyses by optical polarized-light microscopy and X-ray diffraction. More detailed analysis of some mineral phases by scanning electron microscopy was conducted by James Sjoberg of the U.S. Bureau of Mines in Reno. Paul Lechler, Chief Chemist/ Geochemist of the Nevada Bureau of Mines and Geology, utilized X-ray fluorescence and gravimetric methods to obtain a whole-rock chemical analysis of the fossil. The centerpieces of the exhibit are two enlarged photomicrographs of the fossil rib bone (longitudinal and cross sectional views), which were processed by firing or burning the images onto ceramic-covered steel plates by an extraordinary method developed by Michael Sandquist. The strong support of Park Supervisor Chris Macek, and his insistence that the scientific content be preserved in the exhibit, made the project a success.

The text of the exhibit includes a brief discussion of the fossilization process (by Nevada State Park personnel), which leads into discussions of the physical structure revealed in the photomicrographs, mineralogical composition, chemical composition, and analytical techniques used. Also part of the exhibit is the fossil itself, which can be picked up and examined by the public.

Few people know that, although numerous ichthyosaur localities are known around the world, this park contains one of the only partial excavations where the bones have been left in the rock in their original configuration. A visit to Berlin-Ichthyosaur State Park, which is open for tours from Memorial Day weekend to Labor Day weekend each year, is certain to be a rewarding experience for anyone with geological interests. Tours at other times of the year can be arranged by calling (702) 964-2440.

---William A. Fuchs, Geologist