Can Kirk Johnson be right about Wyoming’s Bighorn Basin?
by Allen Best
Kirk Johnson made a tall claim early in his presentation last week at the Denver Museum of Nature and Science. Johnson was once was head curator of paleontology at the museum before being appointed to direct the Smithsonian’s National Museum of Natural History. He’s tall, built like a bear and seemingly emerged from the womb as a native-born storyteller.
He was back in Denver to promote his new book, about Wyoming’s Bighorn Basin. The basin measures 100 miles across, bounded on the east by the Bighorn Mountains and on the west by Yellowstone and the Absaroka Range. The basin’s largest town is Cody, but the the most curiously named settlement is Meeteetse.
The Bighorn Basin, said Johnson, is “maybe the best place on earth to understand the history of our planet.”
I became familiar with Johnson when he led the paleontological excavation at Snowmass beginning in late 2010. I’m accustomed to hearing Johnson making great claims about this and that, extracting truth from a proposition without betraying fact. I have to assume he had great merit in making that claim. He did note that all but two geological ages can be examined in the various outcrops in the basin.
You can examine his argument for yourself in the book, “Ancient Wyoming: A Dozen Lost Worlds Based on the Geology of the Bighorn Basin.” It’s a short book, co-written with Will Clyde, a geologist form New Hampshire with Bighorn cred of his own. You might make it through the book with a large cup of coffee.
Johnson’s most tantalizing comments were about the Paleozoic-Eocene Thermal Maximum, which occurred about 55.5 million years ago. For 10,000 years, the Earth’s temperature spiked 6 degrees C, or about 12 degrees Fahrenheit. The geological record today shows palm fronds in the Arctic from that time. The geologic deposits also show a spike in carbon dioxide in the atmosphere then, as well as a spike in calcium carbonate in the ocean.
Nobody seems to know exactly what happened to cause this spike in global warming, “but we are all really extremely interested,” said Johnson. Some of the research underway to help provide answers has been conducted in a coring (drilling) project in the Bighorn Basin. The basin has 17,000 feet of layered rocks to explore.
One hypothesis, he said, is that volcanic eruptions occurred in coal seams, causing the carbon that warmed the atmosphere and elevated temperatures. Then there’s the potential for methane releases from hydrates (also called clathrates), in which a large amount of methane is trapped within a crystal structure of water, forming a solid similar to ice.
The relevance to today? Johnson didn’t go there at any depth, but I think he could have. Two years ago, I heard him speak before the Colorado Oil and Gas Association annual conference, and there he was not in the last shy in saying that human-caused climate change is a serious issue.
How Johnson uses his authority at the Smithsonian to couch this delicate and important issue of human-caused forcing of climate change is the question I wish I’d asked during the brief question-and-answer session.
But Johnson also had another story to tell, a more personal one that begins in 1879 with the arrival in Wyoming of a young man from Bristol, England. The young man had been commissioned to accompany a valuable mustang to Rawlins, on the new transcontinental railroad. Once in Wyoming, the young man, named Herbert Pearce, decided he wanted to stay. So he homesteaded northeast of Rawlins and south of Casper in what is called the Shirley Basin. It’s lonesome country, wildly beautiful in the tall grasses of June, wildflowers everywhere and, apparently, the cliffs rich with fossils. This homesteader plucked the fossil of a saber-toothed tiger from one of those outcrops and gave it to a geologist.
Some of you may notice a certain similarity to another homesteading story from Wyoming. In 1986, as I had spent a bit of time myself in that country, I read John McPhee’s “Rising from the Plains” and was transfixed by the opening sequence of a school teacher arriving at Rawlins on her way to a rural outpost. And that’s also how Kirk Johnson’s grandmother came to live in Wyoming—and married the homesteading Englishman.
There’s more to the story here, but perhaps it’s best to let you hear Johnson tell it sometime. As I said, he’s a great storyteller. Suffice to say, the family that is central to John McPhee’s book had the ranch that was the next ranch over more or less from that of Herbert Pearce.