Brian Platt, a doctoral student in geology at the University of Kansas rotates the 3-D image of an elephant footprint on a computer screen. It's the first time a 3-D laser scanner is being used to preserve images of trace fossils, or soil impressions left by animals and plants, both modern and prehistoric.
The NextEngine Desktop 3D Scanner, about the size of Cheerios carton, scans images of irregular-shaped objects using a multi-laser system, as it revolves up to 360 degrees. The machine, which costs about $5,000, including cost of the actual computer software, is connected directly to the computer software by a USB port, and then projects a full color 3-D image of what is being scanned onto the computer screen, even while the image is being scanned.
Using this technology, Platt is able to preserve the eroding latex and plaster-of-Paris casts he has made of both elephant and dinosaur trace fossils. He hopes to develop a formula for uncovering the percentage of soil moisture content of fossils in ancient soils, using the scanner. It automatically calculates the volume of the object that it scanned. The formula would predict the moisture content of a soil surface at the time a trace fossil was created. His research falls under the category of neo-ichnology or the study of modern trace fossils.
He said his research, would give paleontologists a more detailed snapshot of the prehistoric climates dinosaurs inhabited. When he began his doctoral studies in 2006 at KU he discovered a dinosaur footprint and "tail drag" in Bighorn Basin, Wyo., a plateau region in Wyoming. This inspired him to find out what the climate was like when dinosaurs left their impressions in soil.
Platt creates plaster-of-Paris casts from footprints created by two elephants at the Topeka Zoo. He does this to simulate the tracks large dinosaurs, such as Sauropods, characterized by their skyscraper height, long neck and tail and herbivorous appetite, according to encyclopediabritannica.com. Platt uses elephants in his experiments because they are the closest in size among modern-day animals. Unlike the elephants, Platt said the Sauropod's footprints, weighing about 4 tons, would have left behind were about "size of trash can lids." Because the two animals are different sizes he uses volume to compare their footprints.
During his experiments, Platt changes the amount of water in the soil the elephants step on in order to recreate the various types of prehistoric environments. After the elephants make their footprints in the sediment mixture he creates, he makes plaster casts of the footprints and stores them in the computer using the 3-D scanner. The scanner automatically measures the footprints' length, width, and overall density of the material.
"Tracks are an ancient snapshot in time," Platt said. "They tell us about the water table, where you are in the flood plain, climate change and precipitation."
Before using the multi-laser scanner, Platt measured the density of his elephant footprints using a nuclear density gauge, a machine that is typically used to measure the density of street pavement. In addition to not being safe because it was radioactive, it couldn't accurately measure the volume of the footprints.
Daniel Hirmas, assistant geography professor at KU, who has conducted research soil clods and modern soil compositions, said determining the density of an irregular shaped object, such as a trace fossil, is almost impossible to do without being able to measure its volume.
The scanner has been instrumental to the effort, Platt said, by automatically determining an irregular-shaped object's volume. The machine accomplishes this by creating a high-definition rendering of the object, using "voxels" or pixels that make the image appear raised or in 3-D. Each voxel is about 120 micrometers or about one-tenth the width of a human hair, Hirmas said. He helped Platt scan the dinosaur and elephant trace fossils that he collected.
He said that Platt's research could produce a more quantitative means of describing modern soils as opposed to just classifying them by their color, texture and rock fragments.
"It all goes back to the soil," Hirmas said.
By conducting these experiments, Platt will also be able to determine what percentage of moisture certain soils contained in prehistoric times.
Jon Smith, post-doctoral researcher in the Kansas Geological Survey, said conducting these experiments could help geologists and paleontologists eliminate some of the guesswork associated with determining climate patterns.
"It's sort of like the black box, Smith said. "There's this incremental error that creeps into what we're doing."
Other geologists say Platt's research boils down to the potential "magic formula" that could be used as a climate model for understanding not only past climate patterns, but also climate patterns in the future.
"People want to understand where we've been to understand where we're going," said KU Geology Department Chair Robert Goldstein. "We don't want what happened to the dinosaurs to happen to us."
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