Site near Aspen an ice-age mystery

Man's possible presence vexes scientists

$PHOTOCREDIT_ON$Snowmass Ski Area fills the background from Ziegler Reservoir near Aspen. Scientists are examining whether early man was in the ice age mix at the site. $PHOTOCREDIT_OFF$ Enlarge photo

Chris Council/Aspen Daily News

$PHOTOCREDIT_ON$Snowmass Ski Area fills the background from Ziegler Reservoir near Aspen. Scientists are examining whether early man was in the ice age mix at the site. $PHOTOCREDIT_OFF$

ASPEN (AP) – As more than 40 scientists continue to study the myriad ice-age findings from Ziegler Reservoir, one mystery continues to vex experts: Was early man at the site?

The question arose this summer at the site outside Snowmass Village, which has yielded a cache of more than 4,800 fossils since a construction worker uncovered the remains of a young Columbian mammoth in October 2010. Workers were enlarging the drained reservoir’s water capacity and installing a new dam; the site is now back under water again.

The possible presence of Paleo-Indians arose when Kirk Johnson and Ian Miller, co-leaders of the dig, and others noticed small boulders where they shouldn’t have been. Several soccer ball-sized stones were found in what was once the middle of the ancient lake. The rocks were next to, above and below a partial mammoth skeleton, Johnson said last week.

The rocks were out of place geologically as no similar stones were found nearby, he said. Paleontologists have established that early man used such stones to hide meat caches in ice-bound spots away from predators and to prevent the protein from spoiling.

So it appeared as if early man may have used Ziegler as a frozen meat locker, except for one problem: Man wasn’t supposed to have been here by then. Most researchers put North America’s earliest settlement by early man at around 14,000 years ago. Ziegler’s ice-age finds are estimated to be between 40,000 and 150,000 years old.

Johnson said he and the other researchers were circumspect when they began pondering last summer whether this was a meat cache, and with good reason: If they are able to find evidence of man – butchering marks left on bones from stone tools, for instance – it would rewrite by 26,000 years the earliest known existence of man on the continent. That scientists were pondering the possible meat cache came to light in the “NOVA” special “Ice Age Death Trap” that aired on PBS in February.

Last year, museum staff and volunteers hoisted a 10,000-pound cast containing the elderly mammoth and the tantalizing boulders onto a flat-bed trailer and drove it to the Denver Museum of Nature & Science.

“We’ve been excavating the rock, chopping it down, and looking very closely for stone tools or other evidence,” Johnson said. “If we find something like that, it would be game over.”

While the boulders have scrape marks, it’s unclear if they are from an early butcher. The site is seemingly far too old to have seen Paleo-Indians, but “in our heart of hearts, it looks like a meat cache,” Johnson said. “It’s the classic case of not enough data, but we’re not done yet.

“We will analyze the hell out of this thing.”

Meanwhile, other scientists, studying everything about the site from its soil, plant life and insects to high-altitude climate change, are to meet in June in Denver. The goal is to synthesize all of the information into a paper that will be submitted to Science magazine.

“If we perform good science and write in a compelling way, this could be picked up internationally,” Johnson said.