Cavers explore miles underground
Hundreds of feet underground a bizarre world exists, a world
where streams disappear into cracks in the ground, translucent
fins of rock drape twisting passageways, and luminescent spires
of rock have slowly grown for thousands of years. There are
scores of miles of underground passages in the fractured bedrock
of the Driftless Region of Minnesota, Iowa, and Wisconsin.
Mystery Cave, Minnesota's longest, stretches for 13 miles.
Explorers have navigated 17 miles of passages in Cold Water
Cave, which begins northeast of Decorah, Iowa, and reaches
across the Minnesota border. Numerous caves lie beneath the
hills and fields of Fillmore County alone.
Few people see these places. Fewer still risk their lives
to discover new passageways, jamming their bodies through
tiny openings, dangling over rocky abysses, and diving in
freezing cold water beneath the earth's surface. But for some,
caving is a life-long pursuit, perhaps an obsession.
Danger and dedication
John Ackerman has gone to tremendous lengths to discover new
caverns, as well. The man has rummaged through and shimmied
under the wreckage of collapsed sinkholes in hopes of finding
openings beneath the precarious rubble. He has used high explosives
to blast through sections too narrow to pass through. He has
bored entrances through bedrock, and he uses a modified track-hoe
(a long-armed backhoe on tank-like tracks) that he calls the
"Cave Finder" to excavate sinkholes and create entrances
He has also spent a fortune buying land above numerous southeastern
Minnesota caves. Ackerman owns the access to most of the area's
caves and claims to have discovered over 40 caves.
"I think what attracts me to it is to be the first person
to walk through the inky blackness of the unknown. You're
the first human being to shine your light through those passages
since the beginning of time," Ackerman said. His enthusiasm
for caves, he says, "is like a hobby that just got out
Ackerman pointed out the serious danger involved in his choice
of activity. "I don't want to say that I'm an adrenaline
junkie, but when you do something as dangerous as trying to
discover a cave there's a great deal of risk involved. Perhaps
the weather can change and you can drown, or if you're in
an unstable part of the cave you can hear what sounds like
sizzling bacon—that's a rock slide," he described.
"In Minnesota we have one added danger: the temperature
of the cave is 47-48 degrees. If you're lucky enough only
to get stuck in a cave, hypothermia can take you very quickly,"
Ackerman acknowledged that what he does is more risky than
"When you're dealing with explosives in caves, if you
screw up once, you automatically die. It forces one to be
very careful," he explained.
Not all cavers put their lives on the line. "I love thrilling
experiences, but I do not have a death wish," said Mystery
Cave State Park Manager Warren Netherton. "I do not go
into something that I do not fully expect to come out of."
Rather than risk death, Netherton and Iowa caver Ed Klosner
have devoted years of their lives to mapping caves. Global
Positions Systems (GPS) do not work underground, so the mapping
of caves is done the same way it has been for decades: by
measuring the dimensions and compass bearing of every single
room and passageway. Klosner and Netherton have been working
on this painstaking process at Mystery Cave since 2006. Netherton
estimated they will be done in 20 years. He laughed, but he
was not joking.
Mapping caves provides an invaluable record for future cavers
and scientists. Despite the effort, it has its own pleasure,
too. "Surveying caves is exciting because you get to
see the spatial relationships of all those interconnecting
tubes," Netherton said. "It's a 3-D puzzle to try
to figure out how it fits together," Klosner explained.
Caving and conservation
Some have criticized Ackerman's bravado in creating new entrances
to caves as detrimental to fragile cave formations, ecosystems,
and groundwater. Ackerman contends conservation is his goal.
Ackerman has put hundreds of acres above and below ground
into a private, undeveloped space he calls the Cave Preserve.
He has been undisputedly generous in allowing scientists and
experienced cavers to study and explore his network of caves.
Climate research, cave mapping, and paleontology take place
in his caverns. The skull of a saber tooth tiger was found
in one of Ackerman's Fillmore County caves, the northernmost
site of such a discovery ever documented.
When asked whether expanding access to so-called underground
wildernesses is counterproductive to protecting them, Ackerman
replied, "That just screams ignorance in huge letters
because you can't protect what you don't know exists."
Winona State University geology professor Toby Dogwiler agreed
that allowing people to experience nature is a key part of
conservation. "The best way to protect Yellowstone National
Park would be to put a fence around and keep everyone out,
but if people can't see how beautiful and special it is, then
they won't care about it," he said. "You can better
conserve caves by making sure that people have access to them,"
That said, minimizing one's impact while traveling through
a cave is important, Dogwiler said. The oil from human hands
can inhibit the growth of stalactites that are hundreds of
thousands of years old, so climb and crawl with caution, Netherton
The greatest threat to Minnesota caves, Akcerman contends,
is not humans below ground but human land use above ground.
Agricultural chemicals, manure, and other pollutants make
their way quickly to cave waters, he said. Ackerman hopes
his Cave Preserve will prevent that at Minnesota's finest
"Caving has turned me into an avid conservationist because
I realized how fragile southeastern Minnesota is," Ackerman
explained. "If a tanker tips over, it's going to run
into the nearest cave and everybody downstream is going to
be drinking that water for eternity."
Klosner described seeing evidence of high-levels of pollution
while in Cold Water Cave. "It's eye-opening to be in
a cave and see foam in the water from agricultural products,"
Hydrology ceases to be an abstract concept after being inside
the water cycle and seeing groundwater firsthand, Netherton
said. "Caves allow you to see where our water goes,"
he explained. "What a unique place for people to be able
to go: between where rain falls on the surface and the aquifers
where it goes."
"Because of years of marketing, people have an idea that
spring water is pure," Dogwiler said. "There's very
little opportunity for natural processing and attenuation
of contaminants [in Karst groundwater]. Whereas in a non-Karst
aquifer there's time for chemicals to break down or absorb
How caves are born
In Minnesota, significant caves only exist in the limestone
and dolomite of the Driftless Region. They form when rain
water, which is naturally slightly acidic, flows through cracks
in the limestone and dolomite bedrock, dissolving the basic
(as in high-pH) rocks and creating conduits through the bedrock.
"If they are large enough we call them caves," explained
Dr. Toby Dogwiler of Winona State University.
In those caves, some of the dissolved rock is left behind
by dripping water. Over thousands of years, this forms all
manner of oddities, famously the spike-like stalactites and
stalagmites. All of the deposits are essentially variations
on this theme, but an incredible assortment exist. Passages
are alternatively decorated with needle-thin "soda straws,"
ribbons of "bacon," and oozing blobs of once-dissolved
This interaction between bedrock and rainwater makes the region's
foundations as porous as Swiss cheese. This Karst topography,
as geologists call it, leads to caves, sinkholes, and streams
that vanish into the underground.
For more information on the Cave Preserve see www.cavepreserve.com