‘Dinobusters’ Use High-Tech to Find Giant Critter’s Bones

New technology that should move the tedious search for dinosaur skeletons beyond the age of the pick and shovel is helping scientists recover the longest dinosaur ever discovered.

By using sonic images of the sandstone beneath a site in New Mexico, scientists were able to detect the dark shadows of bones of “seismosaurus”--so named because it was so big that when it walked the ground must have trembled. Results of the project were presented here Thursday during the fall meeting of the American Geophysical Union.

The early digging consisted of hit-or-miss, time-consuming excavations, but today about 50 workers know precisely where to dig because of a technology developed by the federal Department of Energy to help locate acceptable burial sites for waste disposal. Much of the skeleton has already been excavated but it will take about two years to finish the project.

The process is similar to computer tomography, which uses X-rays to produce images of tissues and bones inside humans, except in this case sound waves are used instead.

“We call ourselves the ‘dinobusters,’ ” said geophysicist Alan Witten of Oak Ridge National Laboratory. Mimicking the theme from the movie Ghostbusters, he added: “Something big in your neighborhood? Who ya gonna call?”

“Seismosaurus” is one of the largest critters ever found, measuring 110 feet in length, according to Peggy Bechtel of the Southwest Paleontology Foundation Inc., Albuquerque, coordinator of the excavation.

The strange beast, which is mostly tail and neck extending from a disproportionately small body, was buried almost intact along a river bank northwest of Albuquerque about 150 million years ago. The exact location is in a federal wilderness area, and it has not been revealed in an effort to discourage uninvited guests who might vandalize the site.

Most dinosaur skeletons are spread over huge areas by erosion and predators, but sonic images of “seismosaurus” reveal that it was buried in a fetal position that it probably assumed at the time of death.

One reason the bones were not carried off by other animals lies in their great size. One chunk from the animal’s vertebra weighs about 3,300 pounds, which was more than the entire weight of the largest other animal known to inhabit that region at that time, said Wilson Bechtel, who is helping to coordinate the excavation.

Once the great beast is fully unearthed, it will be reassembled at the New Mexico Museum of Natural History in Albuquerque and put on public display.

Shotgun on Wheels

The excavation has been accelerated considerably by the technique developed by Oak Ridge’s Witten and Jozef Sypniewski of Wayne State University.

The heart of the process is an 8-gauge shotgun on wheels, which Witten called a “cannon.”

“It fires a slug of soft metal into the ground,” Witten said. “It hits the ground and flattens,” sending out sound waves.

An array of 29 microphones lowered down a well on the other side of the site picks up the sound waves, which are affected by the different materials they pass through. The cannon is then moved two feet away and the process repeated.

By plotting the time at which the sound waves are received, Witten is able to show precisely where the bones are hidden beneath the eight-foot-deep layer of sandstone that has built up over the last 150 million years.

The system works, he said, because sound waves travel 12,000 feet per second through the bones, but only 1,500 feet per second through the surrounding sandstone. The difference in arrival time casts a “sound shadow” that can be used to create an image of the skeleton.

“This animal has been unique,” Witten said, “because usually only one or two bones are found, but here we have one bone after another.”

The images tell workers precisely where the bones are located, including some that broke away from the main skeleton and either slid down a sand dune or were washed a few feet away.

The technology was developed by the Energy Department to help find sites that are suitable for waste disposal and to find past sites that may harbor hazardous materials. It cost about half a million dollars to develop the technology, Witten said, but paleontologists should be able to build their own systems for about $20,000, he said.