Newswise — During the late Cretaceous period, southern Utah looked very different than it does today. With a sea to the east and mountains to the west, the area contained a rich diversity of life and geography. Now all of that is gone, but the records of that time in Utah’s history are preserved in the rocks in and around the Grand Staircase-Escalante region. Scientists working there are available to comment on the rich value of the region to science.

Geologist Cari Johnson has been working in the Kaiparowits Plateau (covering a majority of the original Grand Staircase-Escalante National Monument, or GSENM) since 2005. She has worked in every edge and corner and in much of the center of the GSENM. She studies the Straight Cliffs Formation, a layer of rocks that displays several different environments in which sediment can accumulate. In the west, the sediments show evidence of being deposited by rivers. In the east, the rocks change to beaches and lagoons. She’s interested in what factors drive changes in these environments. “I’m hard pressed to think of many other places in the world where one can study and try to answer these questions with as high quality outcrops as we have in the GSENM,” she says. Insights from GSENM can help petroleum geologists working in other parts of the world to understand how petroleum forms and accumulates underground.


Paleontologist Randall Irmis and colleagues study the evolution of ecosystems in the GSENM area. They’ve found tens of thousands of fossils from plants, snails and crabs, fish, amphibians, lizards, mammals, turtles and crocodilians, all the way to many different dinosaur species. They’ve also discovered more than two dozen new species of vertebrate animals. “Most of these species are unique to GSENM and southern Utah; they are not found anywhere else in the world,” he says. They are trying to answer the question of what makes the GSENM area so ecologically unique and what created such a concentration of diverse life. “Although there was a sea to the east, and mountains to the west, an enterprising dinosaur could potentially have walked from the Arctic Circle down to the Gulf of Mexico.  What prevented these animals from spreading north and south — was it physical barriers, differences in climate and plant communities, changes in sea level, or a combination of factors?”

Cari Johnson | professor in the Department of Geology and Geophysics | 801-585-3782 | [email protected]

Randall Irmis | Paleontology Curator - Natural History Museum of Utah | Office: 801.585.0561 Cell 510.847.5335 | [email protected]