In
August 1999, three sheep hunters were hiking through Tatshenshini-Alsek Park
in northern British Columbia when they came upon a surprise: A human body was
poking out of the ice at the foot of a glacier. They had stumbled upon the well-preserved
(though headless) 550- to 600-year-old body of a man. Alongside “Kwäday
Dän Ts’ìnchí,” or “Long Ago Man Found”
as he is called, were hunting tools, a hat, a fur robe and some food —
a pouch of dried salmon — preserved in exquisite detail. Subsequent tests
have revealed that the man likely lived near the coast in British Columbia but
traveled inland, and was about 20 years old and healthy when he died. The cause
of death was likely exposure in a blizzard. Buried for hundreds of years, his
body was only revealed when it melted out of the glacier.
This scenario is becoming less and less rare, as warming temperatures continue
to melt alpine glaciers and ice fields at a high rate. Bodies and artifacts
have melted out of glaciers on at least three continents and the likelihood
of discovering more — possibly on every inhabited continent — and
older and older ones, grows with each passing year.
In Wrangell-St. Elias National Park in Alaska, a large, centuries-old pile of
caribou dung melted out of the ice patch shown here. Researchers are using the
caribou dung as one variable in a model to locate archaeologically significant
spots that might be revealed by shrinking glaciers and ice patches. If caribou
congregated at the site, it is possible that ancient humans went there too.
Photo by Craig Lee, INSTAAR.
Glaciers around the world have been retreating since the end of the Little Ice
Age around 1850, says Lonnie Thompson, a glaciologist at the Ohio State University
in Columbus. Mountain glaciers lock up about 100,000 cubic kilometers of ice
(as compared to Greenland and Antarctica, which comprise 32 million cubic kilometers
of ice), and most mountain glaciers, including all tropical glaciers, are shrinking,
Thompson says.
The rates of glacial change, however, vary regionally. In North America, average
glacial cover has been reduced by at least 25 percent, though in Glacier National
Park in Montana, two-thirds of the glaciers have disappeared in less than 100
years. In South America, where most of the world’s tropical glaciers lie,
some High Andes glaciers have lost more than 50 percent in area and two-thirds
in volume in the 1990s alone. In Africa and Asia, the majority of glaciers are
thinning rapidly. On Kilimanjaro, glaciers that have persisted for more than
11,000 years have decreased in area by 60 to 70 percent and may be gone by 2020,
Thompson says. Thus, studying glaciers and figuring out what they may be ready
to reveal is a time-sensitive field of incredible importance, he says.
Indeed, “one benefit, if you can call it that,” of global warming,
says Johan Reinhard, a high-altitude archaeologist and Explorer-in-Residence
with the National Geographic Society, is that as glaciers retreat and expose
land that has not been at the surface for thousands of years, more bodies and
artifacts are likely to be found. And “an ancient frozen body has to be
one of the most valuable things on Earth,” says Reinhard, who discovered
the Inca Ice Maiden in the Andes in 1995 and has since been back to the Andes
to search for well-preserved clues to Incan life.
The kind of information that can be retrieved from a frozen mummy is irreplaceable
and neverending, especially as forensic technology keeps improving, Reinhard
says. If recovered soon after it melts out of a glacier, the preservation of
a body is so good that a variety of different analyses can be done, including
DNA, radiometric dating and isotopic analyses, such as were done on Kwäday
Dän Ts’ìnchí. They can even test blood for antibodies
to see what diseases these ancient humans may have encountered, Reinhard says,
and check stomach contents to see what they ate.
“Freezing may be the most ideal condition under which prehistoric organic
remains can be preserved,” wrote James Dixon, an anthropologist at the
Colorado Institute of Arctic and Alpine Research, and colleagues in the January
issue of American Antiquity. Usually, clothing, tools and other organic materials
decompose quickly after deposition, but freezing can nearly perfectly preserve
these items for thousands of years, Dixon says.
It is possible, some archaeologists say, to predict where to find archaeological
sites preserved in glaciers, as certain locations have revealed more artifacts
than others. For example, near the site where Kwäday Dän Ts’ìnchí
was found and throughout British Columbia and the Yukon Territory, archaeologists
have found about 180 ancient artifacts, including hunting darts and arrows,
some of which have dated to more than 9,500 years old, in alpine glaciers and
ice fields since 1997, says Greg Hare, an archaeologist with the Yukon government.
And in Europe, four bodies have melted out of glaciers in the same vicinity
in the Italian Alps. In perhaps the most well-known glacial find, German hikers
found Ötzi (the “Iceman”), a 5,300-year-old body, poking out
of an alpine glacier in 1991 (see Geotimes, February
2004). And last August, an amateur historian found the frozen, preserved
bodies of three World War I Austro-Hungarian soldiers melting out of a glacier
on San Matteo Peak, the site of an important battle between the Italians and
Austro-Hungarians.
Natives in North America and Europe had known trails through alpine glaciers
in mountain passes, and in the High Andes of South America, ancient civilizations
used mountain summits and glaciers as burial and sacrificial grounds, Reinhard
says, making these good places to start to look for archaeologically significant
finds. But “right now, it really is serendipity that you happen to be in
the right place at the right time” to find a body or artifact, Thompson
says. Thus, Dixon adds, “we need to focus our energy on the few [places]
that might.”
So Dixon and colleagues William Manley and Craig Lee created a systematic approach
that combines a variety of biologic (such as caribou ranges), geologic (such
as the extent of glacial movement), and socio-cultural (such as transportation
routes and historical information) datasets with satellite imagery and GIS software
to spatially evaluate the relative archaeological potential of sites. Developing
and testing their model, called MAPIS (Modeling Archaeological Potential of
Ice and Snow), in Wrangell-St. Elias National Park and Preserve in Alaska, the
most glaciated area in the United States, the scientists pinpointed potential
sites for archaeological finds. On two subsequent field surveys during summer
melts, the team found 14 sites with artifacts ranging in age from 170 to 2,880
years old.
This system worked well in the park, Dixon says, and the researchers hope next
to look at another site in Alaska using the same model. While MAPIS is specific
to the region in which Dixon’s team worked, it could certainly be transferred
to other locations, he says, with the caveat that the model is not a formula
that can simply be applied. Geoarchaeologists need first to figure out the cultural,
geologic and biologic variables and components specific to the region in which
they are working.
Even with satellite data, models and increasing glacial melt, however, it is
going to remain difficult to find anything, says Wolfgang Müller, a geochemist
at Royal Holoway University of London who has done extensive work on Ötzi.
“Retreating glaciers will not reveal too many new well-preserved bodies
similar to the Iceman, because it simply requires too many chance events to
happen all at once,” he says — chance events such as just the right
glacial dynamics (not carrying a body downstream and depositing it quickly),
instant burial by a large snowstorm and no scavenging by animals.
Even if all these factors combine to preserve a body, challenges remain to actually
recovering one, even in a spot known to be archaeologically significant, Dixon
says, such as figuring out the timing of when an artifact or body might melt
out of a glacier or ice patch, and being there to recover it. Such research
is interdisciplinary, he says, involving glacial dynamics, archaeology, biology,
anthropology, history and remote sensing.
Procuring funding is also not easy, Reinhard says. For the most part, organizations
don’t want to fund a “going out to search for something that might
not be there” kind of research project, he says. “So we need to get
people to understand the incredible value” of these finds, and quickly,
because “once these things are gone, they’re gone forever.”
Megan Sever
Link:
"Iceman's
origins," in the feature "Geoarchaeology:
The Past Comes to Light," Geotimes, February 2004
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