Completing their dig at Snowmass Village, scientists from the Denver Museum of Nature and Science and other institutions now wonder if an ancient earthquake that created quick sand explains the unusual number of bones from juvenile mastodons.
“What is so curious about this site is that we are regularly finding parts of small animals,” said Johnson, a paleontologist and chief curator of the Denver Museum of Nature and Science.
In the lower levels of the ancient lakebed, most of the bones are of mastodons, a creature somewhat like the elephants of today.
Scientists believe the remains of fossils, trees, leaves, and insects were deposited more than 40,000 to 50,000 years ago, as radiocarbon dating has proven useless. The technique is useful only on more recent remains. But they think the lakebed can be no older than 150,000 years. That’s when a massive glacier shoved bits of soil and rock into a mounded ridge, called a terminal moraine, on which the lakebed was then formed.
Johnson said the scientists don’t yet have the evidence to support this hypothesis. One piece of evidence will come from study of the mastodon tusks. Like trees, they display growth cycles, revealing even the season of the year when the animal died. If the tusks reveal identical seasons for many of the tusks, they likely had a common killer.
Study of sediments will also reveal whether an earthquake caused creation of quick sand.