On a hazy Thursday morning, Jacob Thacker is helping a group of a dozen people see the landscape of southcentral Montana through a different lens. “We are looking at a sculpted landscape, because we have nature’s sculpture right here." Thacker said.
Thacker is a geologist with Yellowstone Bighorn Research Association, a non-profit organization based in nearby Red Lodge that specializes in earth science research and education. He is one of the guides on the geo-paleo tour at Tippet Rise.
“So this is kind of one of the fun things about doing this tour at Tippet Rise which is about art and sculpting things to think about and evoke emotions for geologists this is our sculpture that we get to look at and think about, because we have natures sculpture right here." Thacker said.
Tippet Rise is a 12,500-acre working ranch at the foothill of the Beartooth Mountains. The ranch is an open-air art center, known for its large sculptures that sit among the rolling prairie landscape. But the sculpture the tour group is learning about is the landscape itself.
Thacker explains, although we are standing on a high bench overlooking the property, our feet are planted on what was once a river bottom.
“So we start this tour in the youngest part of geologic history,“ Thacker said.
“As geologists, we think about earth history kind of like a book and the beginning of the book starts at the oldest and we come all the way to the youngest. Well we're going to read the book backwards today.”
This 150,000-year-old rock deposit is the youngest rock on the property, but even from the end of the geologic book, we can get a glimpse of the first chapter.
“So we’ve got a ton of time here, you look up to the high Beartooths you’ve got pieces of material almost four billion years old,” Thacker said.
Thacker clarifies it’s not the oldest rock, but the microscopic mineral zircon has been found in these mountain peaks. We try to guess the age of the earth.
“6 billion, any other guesses? 4.2. Okay, we’re going to go somewhere in the middle but closer to the 4.2.- 4.56 billion with a 'B' is the scientifically accepted age of the earth.” Thacker said.
With so much time to cover and only a few hours in the tour, we load up into vans and head to our next stop.
After climbing up a grassy hill, our other tour guide also with YBRA, Matt Knight sets the tone for this chapter of geologic history.
“We’re now into Mesozoic rocks, so middle life, if you want a direct translation. This is actually the Hell Creek formation, which is quite famous for dinosaur fossils.” Knight said.
Even as we talk about dinosaur bones, Knight reminds of the enormous time scale we are covering today.
“A lot of times people think dinosaurs were all together, well stegosaurus and tyrannosaurus never existed at the same time. We’re actually closer to tyrannosaurus than stegosaurus was,” Knight said.
We look at rocks beneath our feet that are more speckled than our first stop.
“This is a record, this is the book that’s right in front of us, for us to be able to try and read and figure out what earth was doing back then,” Thacker said.
One mystery solved by reading rocks was what happened to the dinosaurs. The answer came from a father and son team.
“They started looking at the cretaceous tertiary boundary. It’s a very sharp boundary, it actually exists here just off of the Tippet rise property,” Knight said.
The bounty presents as a thin, dark band, which after testing contained a mineral not often found on earth, so they hypothesized there had been a large meteor impact at the time. Their hypothesis set off a hunt to locate an impact site, which was eventually found off the coast of Mexico.
At our final stop of the day, we see an entire petrified tree trunk laying on its side just off the road.
“This has actually been identified at least tentatively as an old member of the magnolia family,” Knight said, which helps us imagine a very different climate from the dusty road we stand today.
“Sub tropical very hot, very hot, very vegetated environment here,” Knight said.
Our group spread out looking for imprinted leaf fossils in the rocks at our feet.
Temia Keel holds a rock open and shows a small dark squiggle.
“Some twig that was picked up in a river flow, which is kind of cool. It’s an amazing place to be. It’s overwhelming you know really, when you think of the span of time and how much there is to learn,” Keel said.
Keel lives in Bozeman, and brought her daughter and granddaughter visitng from Tennessee on the tour. She says she was recently in Ekalaka looking for fossils
“And then to see that it’s here as well. I really did not have a sense for the range of Hell Creek. We're a big state but gosh were not all that different from one part to another,” Keel said.
We head back to the visitors center passing a looming sculpture that resembles a large tree with no leaves. The sculpture titled 'Iron Tree' was made by Ai Weiwei in 2013. Even though the iron is rusted, it looks brand new compared to the 80 million-year-old petrified tree we just saw. But that was always the intention at Tippet Rise, to have sculptures on a naturally sculpted landscape.
