Ghost Reef Fossil Find

October 13, 2014


Photographer: Joe Bauman
Summary Author: Joe Bauman
October 2014 Viewer's Choice
High in the mountains of Uinta-Wasatch-Cache National Forest, in Utah’s Albion Basin, a ghost reef hunkers near a popular hiking trail. Low boulders that represent parts of the reef were brought to my attention by Allison Ceresa Genet -- shown in the bottom photo. Thousands of small sharply defined remnants of creatures that lived around 330 million years ago cover the surfaces of several boulders. The vast majority of the figures, which are white or gray and embedded in dark limestone, are solitary rugosan corals, according to Utah’s state paleontologist, James I. Kirkland. Rugosan corals (horn corals) dating to the Mississippian subperiod are found throughout Utah. In boulders left from the ancient reef, horn coral fossils are preserved in three dimensions; erosion cut across them directly through the center, lengthwise or diagonally, resulting in a variety of patterns. Depending on how Nature slices it, the corals look like circles with spokes radiating from the middle, fluted shapes like tiny buffalo horns, spiky vanes, icicles jutting from a semicircle or sprays of white streaks. Other fossils -- some of which are shown here with a coin for scale -- that are not rugosan are even more interesting: ammonites, what looks like a small straight nautiloid, a carapace that's similar to those of Cambrian period shrimplike animals, a possible crinoid, and some clearly rendered but hard to identify shapes. A few seem to show fossilized remains of soft tissue. Horn corals and many other species were annihilated during Permian Extinction approximately 250 million years ago.
Photo Details: Top - Camera: NIKON D70; Focal Length: 70mm (35mm equivalent: 105mm); Aperture: f/5.6; Exposure Time: 0.0040 s (1/250); Software: Adobe Photoshop Elements 2.0. Bottom - same except: Focal Length: 35mm (35mm equivalent: 52mm); Aperture: f/4.2; Exposure Time: 0.0025 s (1/400).