Arts & Humanities
Scientists have discovered a huge concentration of thousands of dinosaur footprints in a small area of the U.S. Southwest.
Before reading, display a U.S. map and ask students to identify the locations of Arizona and Utah. If your map is detailed, perhaps students can identify the locations of Page, Arizona, and Kanab, Utah. This weeks news story takes place in a remote spot about halfway between Page and Kanab.
Next, introduce these words that appear in the News Word Box on the students printable page: border, determined, erosion, scattered, sandstone, and upright. Discuss the meanings of any of those words that might be unfamiliar. Then ask students to use one of those words to complete each of these sentences:
Read the News
Click for a printable version of this weeks news story Scientists Marvel at Dinosaur Dance Floor.
More Facts to Share
You might share these additional facts with students after they have read this weeks news story.
About 1,000 dinosaur footprints and tail-drag marks were discovered in a remote site along the Arizona-Utah border in what is now the Vermilion Cliffs National Monument. The new discovery is rare because of the large number of tracks found in a small area. "Unlike other trackways that may have several to dozens of footprint impressions, this particular surface has more than 1,000," according to researchers who recently published their findings in the journal Palaios. [See photos of the site.]
Scientists believe that during the Early Jurassic Period the U.S. Southwest was covered with a field of sand dunes. This desert area was larger than the Sahara Desert; it covered much of Utah, Wyoming, Colorado, New Mexico, Arizona, and Nevada. Low oasis-like watering holes were located between the dunes. These tracks were found near one such watering hole; the wet, soft sand at the hole would explain why the tracks were so distinct and deep, the scientists say. "You can see the mounds of the sand going around their toes," Marjorie Chan, professor and chair of geology and geophysics at the University of Utah, told National Geographic.
Winston Seiler, a geologist at the University of Utah, studied the shapes and sizes of the tracks. He suggests that four different dinosaur species gathered at the watering hole based on his identification of four distinct types of tracks:
--- long, three-toed prints, with heel marks, 10 to 16 inches long; these were likely made by upright-walking dinosaurs with body lengths of 16 to 20 feet (smaller than Tyrannosaurus rex)
--- three-toed tracks, 4 to 7 inches long, left by small dinosaurs only a few feet tall
--- circular tracks, 6 to 11 inches long, left by creatures that walked on four legs and were the largest dinosaurs at the site; the tail-drag marks are associated with these footprints
--- additional tracks, 7 to 10 inches long, made by dinosaurs that ranged from 6 to 13 feet in length
Alan Titus, a paleontologist at Grand Staircase-Escalante National Monument in Kanab, Utah, has not seen the site in person but is not convinced that these are really dinosaur tracks. "I've observed thousands of tracks in early Jurassic rocks of the Colorado Plateau and have never seen one that looked like the one [the researchers found]," he told National Geographic.
Chan first visited the site of the dinosaur tracks in 2005 with a U.S. Bureau of Land Management ranger who was puzzled by them. Chan initially called them potholes, which are erosion features common in desert sandstone. "But I knew that wasn't the whole story because of the high concentration and because they weren't anywhere else nearby but along that one surface."
Seiler, who first saw the tracks in 2006, had similar thoughts. "At first glance, they look like weathering pits -- a field of odd potholes," he said. "But within about five minutes of wandering around, I realized these were dinosaur footprints."
Jim Kirkland, Utah's state paleontologist, has not been to the site, but he has seen many of the researchers' photos and agrees with some of their conclusions. "Some of the [imprints] are definitely tracks," he said. Kirkland is a little more leery about the tail-drags, which are rare and can be difficult to verify.
Seiler and Chan say they remain certain that the tracks are not erosion potholes. Upon close inspection, many of the impressions are ringed by mounds of displaced sand that had to be formed when the sand was soft, before it was turned to rock," said Seiler. He also identified the repeating patterns of the footprints and, in some cases, three clear toes. In addition, the tracks "are rarely flat and are typically oriented at an angle and indicate a clear direction of travel" to the west-southwest. The evidence that these are dinosaur tracks outweighs evidence for the other possibilities, he said.
Think About the News
Discuss the Think About the News question that appears on the students news page. You might use the think-pair-share strategy with students to discuss this question. If you use this strategy
Social Studies geography. Ask students to identify on a U.S. map the borders of Arizona and Utah, where this weeks news story takes place. Then ask them to identify how many states border Arizona and Utah. (Arizona is bordered by five other states -- California, Nevada, Utah, Colorado, and New Mexico -- as well as the country of Mexico. Utah is bordered by six states -- Arizona, Nevada, Idaho, Wyoming, Colorado, and New Mexico.) Then provide students with a U.S. outline map. [alternate map].
--- For younger students: Tell students two states in the United States share their borders with eight other states. Ask them to use their maps to identify the two states that have eight neighbors.
--- For older students: Make the task a bit more difficult. Ask them to use the map to find the state that has the most neighbors (that is bordered by the most states). Their research will tell them that there are actually two states that each have eight neighbors.
--- Answers: Two states -- Tennessee and Missouri -- share their borders with eight states. Tennessee shares its border with Kentucky, Virginia, North Carolina, Georgia, Alabama, Mississippi, Arkansas, and Missouri. Missouri shares its border with Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas, and Nebraska.
Science careers. An archaeologist studies past life and culture based on remains left behind and often dug up. A geologist studies the materials that comprise our planet. What do other scientists and scholars study? Challenge students to tell what each of these scientists do; you might ask them to use library resources to match each type of scientist to what he or she studies.
--- For younger students:
Use the Comprehension Check (above) as an assessment. Or have students work on their own (in their journals) or in their small groups to respond to the Think About the News question on the news story page.
Lesson Plan SourceEducation World
SOCIAL SCIENCES: Geography
GRADES K - 12
NSS-G.K-12.1 The World in Spatial Terms
See recent news stories in Education Worlds News Story of the Week Archive.
Article by Ellen Delisio and Gary Hopkins
Copyright © 2009 Education World