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obvious to everyone that what was being uncovered at the site was
truly remarkable and perhaps unprecedented. On the other hand,
the construction crew had a very real deadline to meet. The ques-
tion on everyone’s mind was, “Can we really pull this off in time?”
After the furious schedule of the salvage operation in 2010, it
was clear that site was vast and important. The bladerunning
technique had to be abandoned in 2011 because there were simply
too many fossils. An army of highly trained volunteers was
brought in with the task of excavating dirt, rocks, and bones for
eight hours a day, six days a week. The clank of metal shovels
echoed through the subalpine forest day after day amidst project
co-leader Kirk Johnson’s imploring calls to “dig faster!” and an
occasional cry of “bring me the head of Ziggy the sloth!” During
the 2011 field season alone, the crew removed roughly 8,000 cubic
meters of sediment, all by hand, and recovered more than 5,000
large bones and tens of thousands of smaller ones. On average, a
large bone was pulled out of the ground about every five minutes
for the entirety of the dig. The work was hard, no doubt, but the
allure of discovery was a powerful force!
NEXT, A WOBBLE, AND THEN THE FINISH LINE
Each night, after meals prepared by yet another group of volun-
teers, the team would get together for a daily round of show-and-
tell. It was a fun and light-hearted way to recount the day’s finds,
as well as to encourage and challenge each other as the days grew
longer. One particular night, toward the end of the 2011 season, a
visitor questioned the team about the long-term plans for the site.
Until then, with so much work to be done before the impending
deadline, little energy was directed at anything but moving the
next pile of dirt. With the crowd perking up a bit, and the transfer
of thought moving from the present to the future, he suggested
that the site was of such scientific importance that the team
should reconsider their agreement with SWSD and push for some
sort of effort to preserve the site as an open-pit paleontological site for those interested in studying aspects of the site that were not
where visitors could view the specimens laid out as they were
discovered.
Intense debate, alternatives, and opinions were thrown about
late into the night. The enlarged lake basin, which by then was
nearly ten meters deep, was supposed to be filled with water in
just a few short months. What lay before us was a pretty simple,
but terrifying, conundrum: “Do we want a palace (park/museum)
or a puddle (reservoir)?” Arguments went back and forth, with the
idea of preserving the site gaining traction.
At that point, an observation was made. The site was incredible
to be sure. And the preservation of the fossil material—including
intact conifer cones and sedge leaves that remained green after
nearly 100,000 years of burial, not to mention tusks that were so
pristine that they reflected the image of the person holding
them—were things that none of us had ever seen. But what was it
about the site that allowed for such preservation over such a long
period of time? Was it an open pit in the past? Obviously not—it
was a lake. If we really wanted fossils that remained in the lake
sediments to be preserved for future generations, what better way
to do this than to return the site to its original condition? After
still more debate, a final decision was made: We would return the
site to its original condition and landowner intent, that is, a lake.
Knowing they could make good on their promises, Kirk Johnson
and project co-leader Ian Miller breathed sighs of relief and got GSA TODAY | www.geosociety.org/gsatoday
back to work.
Remarkably, the SWSD had also been thinking about the
long-term plans for the site as they neared completion of the
dam. On their own initiative, the SWSD built a gravel road that
extended down to the bottom of the lake basin. Their idea was
that some time in the future, during summer months in years
where the demand for water was low, the lake could be drained
and a new round of excavations could take place. Thus, the
delicate dance between science and construction had come full
circle—from the uneasy wariness of the first few days after the
initial discovery, to full cooperation and promises kept—and
work at the site was complete.
AND FINALLY, ON TO THE FUTURE
Using a combination of dating techniques ranging from radio-
carbon and cosmogenic surface-exposure dating to uranium
series and optically stimulated luminescence, scientists ultimately
determined that lake sediments at the site spanned 85,000 years,
from ~140,000 to 55,000 years before present, including the end of
Marine Oxygen Isotope Stage (MIS) 6, all of MIS 5 and MIS 4,
and the earliest part of MIS 3. Importantly, the site provides the
first opportunity to study ecosystem response to climate change
during the Last Interglacial Period (MIS 5) at high elevation
(~2705 m above sea level) in the Colorado Rockies.
Thus far, scientists have used a variety of environmental
proxies, including pollen, plant macrofossils, tree rings, macro-
and micro-vertebrates, and macro- and micro-invertebrates, as
well as close examination of the stratigraphy, particle size distri-
bution, and geochemistry of the lake sediments, to reconstruct
changes in environmental conditions at the site over time.
However, there are still tremendous opportunities for future work
covered by the original studies. Vertebrate fossils are housed at the
DMNS; pollen, plant macrofossils, and invertebrates (insects,
chironomids, mollusks, and ostracodes) are stored at various
academic institutions; and sediment cores that span the entire
lake sequence are available for study through the USGS. It is our
hope that the collaborative spirit of the Snowmastodon Project
will inspire scientific studies for generations to come.
REFERENCE CITED
Pigati, J., and Miller, I., eds., 2014, The Snowmastadon Project: Quaternary
Research, v. 82, no. 3, p. 473–634.
Manuscript received 28 Dec. 2014; accepted 9 Feb. 2015.
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