Mammoths roamed the San Luis Valley

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Mammoths were one type of megafauna to roam the San Luis Valley about 15,000 years ago.

Mammoths were one type of megafauna to roam the San Luis Valley about 15,000 years ago.

Stratigraphic layers as seen from an undisturbed surfact at the Mr. Peat Site.

Stratigraphic layers as seen from an undisturbed surfact at the Mr. Peat Site.

Location of the four study sites in the San Luis Valley.

Location of the four study sites in the San Luis Valley.

by Mary Lowers

 

During the Pleistocene Era, two million to ten thousand years ago, several species of megafauna grazed in the San Luis Valley (SLV). There were mammoth elephants, including the largest of them all, the Columbian Mammoth, and herds of mammoth bison, known as Extinct Bison chomping down in grasslands and wetlands on both sides of the valley. Rich expansive grassy meadows in the mountain parks separating the various ranges of the Rocky Mountains were wetter then, and these huge animals had little to worry about in the way of food scarcity or predators until humans showed up. But when was that?

For many years archeologists have established that the so-called Folsom people hunted mammoths in the SLV 15,000+/- years ago. In the mid 1990s Margaret Jodrey of the Smithsonian Institution excavated a Folsom hunting camp at the Cattle Guard Site near the Great Sand Dunes. The hunters at this site specialized in hunting the huge Extinct Bison. Other sites establish the presence of Clovis people 10,000+/- years ago in the SLV.

In the ensuing decades, an ongoing investigation into the association of mammoths with humans in the SLV has proceeded. The three main sites being investigated by archeologists and geologists are the Villa Grove, Magna, Mr. Peat and Scott Miller mammoth sites. Much of the study of these sites has been undertaken by faculty and students from Adams State University and has been written about by Jared Beeton, Ph.D who is a Professor of Earth Sciences at Adams State, in the SLV Historian. Many quotes in this story are from his work.

Species found at the SLV sites include Columbian Mammoths, largest of the extinct mammoths. This monster was 13’ tall compared to a very large African elephant of our times, which might manage to reach 11’. Each mammoth went through five or six sets of teeth in their lifetime. This explains why mammoth teeth have been found at all the sites studied. If you want to see a mammoth tooth, the Crestone Historic Museum has one on display.

What kind of mammoths were here and when they were here is a lot clearer than when hunters entered the scene. We know both the Folsom and Clovis peoples hunted mammoth, but it’s becoming an increasing possibility that there was a culture predating these groups who are easily identified by the style of their projectiles. Beeton says, “The mysterious pre-Clovis culture, who were most certainly here before Clovis . . . we know little about them . . . we don’t even know what their toolkit looked like and as a result we really don’t know what we are looking for.” Holy history’s mysteries!

So here’s what archeologists and geologists have found out at the four SLV mammoth study sites. The sites were chosen carefully by looking at archeological surveys and geologic studies.

The Villa Grove site is a buried alluvial fan proceeding eastward from the San Juan Mountains. Digging carefully down into the old stream bed, archeologists and geologists discovered a buried landscape called a paleolandscape. The buried soils represent landscapes that were once on the surface. Humans and animals wandered over this landscape dropping things and even dying there, which is how buried soils become windows to the past.

At the Villa Grove Site “the gully was initially carved by a small low-energy stream that subsequently filled in with gravel sediment during high energy floods.” Mammal bones were scattered throughout the gully during these floods. While human evidence has not yet been unearthed at this site, “there’s a high potential for the presence of early human cultural deposits at the Villa Grove site.” Scientists found through geologic studies that the climate and landscape were stable at this site for a long time, maybe even a few thousand years. This would have made the site conducive to mammoth and human occupation.

The Mr. Peat Site is located at the south east side of the SLV. It is on private property and in the past, peat was cut commercially on the land. “The site is represented by scattered mammoth and Extinct Bison bones along with projectile points.” A total of six obsidian points have been uncovered at the site. It is thought there’s a moderate chance of finding more human evidence at this site. “The extent of prehistoric occupation . . . has been picked over by non-scientists.”

Dating here and at the other sites in the SLV is done in part by dating the peat layers. The oldest layer is mucky peat with stratified woody peat above that and the entire soil package topped with organic silt (from decomposing plants or animals). “Peats are easy to date because of their rich organic deposits and because they are full of organic matter for radiocarbon dating and they tell us about the paleoclimate.” Mucky peat, for example, is deposited in a shallow-water, possibly wetlands, environment.

The Scott Miller Site is located on the Monte Vista Wildlife Refuge. The site contains Columbian Mammoth and Extinct Bison bones along with over a thousand projectile points. “Thick peat deposits at the site show a localized rising of the water table resulting in wetlands conditions.” The Scott Miller Site is considered favorable for finding evidence of early human occupation. This site has been continuously used by Paleo-Indian and historic people.

The Magna Mammoth Site was identified first by the University of Colorado Field School in the 1970s. The site now is in a subdivision south of Villa Grove. The site consists of peat layers below covered by rich organic deposits. One of these layers is yellow-greenish clay, where human remains have been found. “The best chance for finding evidence of pre-Clovis people at the Magna Site is to find and analyze additional mammoth remains.”

Steve Holen is an expert on how humans break bones to extract marrow and how they fashion tools. Holen has studied this early human hunting behavior in North America and East Africa. He says, “Humans leave distinct patterns on the bones that are different from lions, hyenas or being trampled by elephants.” At the Villa Grove Site Holen has uncovered mammoth bones with a possibly human-made green fracture, which can only happen when the bones are fresh and still supple. While not conclusive evidence of pre-Clovis human occupation of the SLV with the Columbian Mammoth at the end of the Pleistocene, this sort of find keeps the mystery alive and gives a reason to research further.

As for the disappearance of megafauna in the SLV, researchers do not agree on the cause of the extinction. One theory holds that humans’ hunting wiped them out. Another idea is that disease ended their existence. Some scientists think an asteroid or a comet may have killed off these giant beasts. Others suggest their demise may have come about due to climate change depleting the environment of the volume of food necessary for the megafauna’s survival.

Mammoths were one type of megafauna to roam the San Luis Valley about 15,000 years ago.

Mammoths were one type of megafauna to roam the San Luis Valley about 15,000 years ago.

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