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In the Monument Valley Navajo Tribal Park.

A journey to dinosaur country

Merja Salmitie

 

Colorado and Utah, in the United States, are real dinosaur country. There is such an abundance of the remains of those ancient masters of the world that today the remainder of a fossil-bearing layer forms an entire wall of the Dinosaur Quarry building and there is still enough of dinosaur bones to sell to tourists.

When walking in the Colorado wilderness, one can find fossils such as birds’ footsteps imprinted in stone. Or one can have an experience something like that of an 80-year-old grandfather from Grand Junction.

“My six-year-old grandson came over and said he’d go to the backyard to look for dinosaur bones. After some digging he returned to tell us he’d found something. We went to see and there really was a dinosaur’s femur. His mother said that it must have belonged to Tyrannosaurus rex, but I’ve found some bones myself and I think it was a Brachiosaurus bone.

”Denver is situated in the Rocky Mountains at a height of one mile or 1,600 metres. When we approach the Denver International Airport, the scenery has long been monotonously flat. As the teepee-style airport building comes into sight, there is still no sign of the mountains. Only after 20 miles drive west past downtown Denver do we hit a mountain road that has emergency ramps for trucks that have lost their brakes. The road winds past ski resorts, hot springs and a place called No Name.

Grand Junction is located at the height of 1,400 metres, where the Colorado and Gunnison rivers meet. The world’s first Brachiosaurus was discovered on Riggs Hill. To the southwest of the city is the Colorado National Monument, a place of natural beauty with red sandstone canyons. There may be a rattlesnake lurking behind any stone.

Nearby is Grand Mesa, the largest flat-top mountain in the world. ‘Mesa’ means a usually isolated, smallish mountain with steeply sloping sides. The flat upper part of a larger mesa can form a plateau. The average height of Grand Mesa’s lava covered plateau is 3,000 metres. Above its slopes you may see a Golden Eagle soar and rest awhile on a tree branch before continuing on its journey.

Dinosaur bones for sale

To the south, there is ”Switzerland of America”, Mount Sneffels of the San Juan range. In the town of Ouray nearby, you can buy dinosaur bones and trilobites. Opposite the souvenir shop, there is the Sandman, a geologist who came to the area just before the mining industry came to an end. He has earned his living, since 1972, by making sand patterns in bottles. The natural sands of different colours come from 15 different states, mostly from the west and southwest United States. So far no blue sand has been found. The clay content of the sand is high, which is why the dinosaurs, moose, buffalo, birds and clouds stay in place in the patterns of the sandbottles. The Sandman indeed gives them a lifetime guarantee.

South of Ouray, you can drive on a million dollar highway. When the road was nearly finished, it was discovered that the roadbed contained gold ore. Tearing out the asphalt, however, would have been too costly. The road to Red Mountain was, therefore, called the Million Dollar Highway. Red Mountain gets its colour from the very high content of oxidised iron. If you continue your trip to the town of Telluride, you might be lucky enough to catch a glimpse of Tom Cruise and other celebrities who live there.

We notice the pressure change in our ears as we drive in the mountains and then in the valleys. On the way to the Black Canyon of the Gunnison National Park, you can see a hundred or more mule deer, several elks, beavers, Blue Grouse and Canada Jays. You can see large herds of elks especially in the valley owned by Walt Disney’s daughter, where hunting is prohibited. The Black Canyon is 85 kilometres long and as much as 914 metres deep.

There is a dinosaur museum in Fruita, close to Grand Junction. The museum bustles with life, since the staff are cleaning fossils behind glass walls, and you can open a window and ask them questions. You can also put a sheet of paper on metal plates and colour dinosaurs. Visitors can brush fossils from the sand or print the footprints of various animals on it. The trombone sound of Parasaurolophus can be produced with a pump, while an earthquake can be experienced on a moving floor. You can collect dinosaur stamps from the various exhibits.

2000 bones in a rock

Soon after the town of Loma, we cross the state line into Utah. In the desert, the home of rattlesnakes, scorpions and black widow spiders, people can admire rock carvings made by Native Amer-icans some eight or nine thousand years ago. Oil pumps rise from the desert and, sometimes, you can see antelope feeding near them. There, they are safe from hunters.

The Dinosaur National Monument is located in the eastern part of Utah and the northwestern part of Colorado. The building that houses the dinosaur quarry is situated in Utah, eleven kilometres north of Jensen. Paleontologist Earl Douglass began to explore the area in 1908, and it was not by chance that he arrived in this area. Considerable dinosaur finds had been made in similar rocks, the Morrison Formation, in Cañon City, Colorado, and Como Bluff, Wyoming. The following year, he found the first eight Apatosaurus bones (better known as Brontosaurus) and, later, thousands more were discovered in the area, from ten different species altogether and including some entire skeletons.

Even though Douglass continued his excavations for several years, he did not take all the finds to museums. One of the walls of the quarry building is actually a rock containing more than 2000 dinosaur bones. The sandstone reveals 150-million-year-old bones of Apatosaurus, Diplodocus, Stegosaurus, Camarasaurus and Allosaurus that visitors can actually touch with their own hands. There are no bones of Tyrannosaurus rex, the “cousin” of Allosaurus, in the quarry, since it lived millions of years later. They both belong to the Avetheropoda, but Allosaurus, which walked on its hind legs, was the terror of the Jurassic period with its slashing claws and razor-sharp teeth. In the surrounding area, there are shops where visitors can buy souvenirs, such as dinosaur bones and trilobite earrings.

The Colorado Plateau extends from northwest New Mexico through western Colorado to east and southwest Utah and northern Arizona. In the Jurassic period, a hundred million years ago, it was ruled by dinosaurs. When they died, some of them were covered with mud and sand and finally buried deep in the ground, where their bones fossilised (that is, were filled or replaced with agate, quartz, iron, calcite and other minerals) leaving the cellular structure clearly visible. As a result, we have fossils formed partly of stone and partly dinosaur bone.

Radiant bones

Mikko Haaramo from the University of Helsinki (see also Universitas Helsingiensis 1 / 2001) advises people to measure the radiation in dinosaur bones, since the bones of terrestrial vertebrates contain uranium and thorium. For example, a dinosaur rib bought in Lin Ottinger’s Rock Shop in Moab, Utah, gave values over 10 counts per second when measured with a beta Geiger counter. Seija Suksi from the Radiation and Nuclear Safety Authority, Finland, says that such a value is not dangerous, however. Michael Tillander from the Laboratory of Radiochemistry, Department of Chemistry, University of Helsinki, agrees with her, even though he measured higher values and gamma radiation with his bigger equipment.

Juhani Suksi from the same laboratory says that radioactivity in the bones originates in the daughters of uranium as a result of the radioactive decay of uranium included in the bone. The uranium ended up in the bone during the long period it was buried in the ground, since uranium is quite a mobile element in such conditions and bone has the tendency to bind to uranium.

Radioactivity is easy to detect in dinosaur bones, since such a long time has passed since the accumulation of uranium that its daughters have had time to achieve radioactive balance with the parent uranium (that is, there are many other radioactive elements in the bone besides uranium that together create radiation). On the basis of a gammaspectrometric analysis, Juhani Suksi determines that the radiation detected in the rib mostly originated in the isotopes of bismuth (Bi-214), lead (Pb-214) and radium (Ra-226). Mikko Haara-mo estimates the late Jurassic rib to be some 140–160 million years old, most probably 150 million years, during which time the radioactive substances have accumulated in it and decayed into daughter nuclides.

From the above-mentioned Rock Shop, you can also buy fossilised dinosaur dung, dinosaur eggs, ammonites, trilobites and amber.

West of Moab is the Dead Horse Point State Park. It is the top of a peninsula 1,731 metres above sea level and surrounded by cliffs on three sides. The narrow strip of land, called the neck, connects it to a mesa. Legend has it that some hundred years ago the place was used as a paddock for wild mustangs, prairie horses, that wandered on the top of the mesa. Cowboys surrounded the horses and herded them through the narrow neck to the verge of the cliff. The neck was then closed with branches and bushes. This way, they created a natural paddock surrounded by steep rock walls with no way out. Then the cowboys would choose the best horses and set the others free. Once, for some unknown reason, the horses were left in the dry paddock, where they died of thirst with the Colorado River some 600 metres below as their final view.

From the Dead Horse Point, there is a view to the Shafer Trail, where the dramatic closing scene of Thelma and Louise was filmed. The Shafer Trail used to be a cattle trail and was later used by uranium seekers. From the Dead Horse Point, you can also see the Canyonlands National Park. The Green and Colorado rivers have carved the sandstone layers into hundreds of canyons, mesas and arches. Where soft and hard vertical stone layers alternate, rivers divided the plains into basins. If the summit width is less than the height, it is called a butte. In the northern part of the park, there is an area called Island in the Sky, where the Shafer Trail starts.

East of Moab is the Arches National Park with more than 2,000 stone arches. Balanced Rock defies gravity on its weak base until one day erosion will cause it to fall. Sequences in Thelma and Louise were filmed here as well. As the two women are driving their 1966 T-bird convertible, The Three Gossips, remains of a large sandstone mesa, can be seen in the background. By the Courthouse stone tower, they are stopped by a policeman. An Indiana Jones film starring River Phoenix was another film shot in the Arches National Park.

The writer is a molecular geneticist and freelance journalist.