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Mima Mounds

Mighty_Emperor

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I bet she does!!

Tuesday, February 17, 2004 - Page updated at 12:00 A.M.


Ecologist shares findings on mystery of Mima Mounds

By Ian Ith
Seattle Times staff reporter


Linda Storm believes the Mima Mounds, those baffling bumps that pock the prairies of Southwest Washington, were ecological gold mines to the Indians who depended on the wild plants that grew on them.

For the past few years, Storm has been sharing her ideas mostly with local botanical groups and other like-minded ecologists, most of whom are familiar with the mounds and the curiosity they evoke.

Yesterday, the longtime Seattle wetlands ecologist and University of Washington doctoral student got a rare chance to introduce her ideas about the Mima Mounds to the American Association for the Advancement of Science meeting in Seattle.

Her talk was part of a panel discussion called "Reflections on the Salish Sea: Coast Salish Research and the Future of Pacific Northwest Ecosystems."

"I feel totally honored," said Storm, who has worked in the Seattle office of the Environmental Protection Agency for 20 years. "And kind of amazed, actually."

ROY SCULLY / THE SEATTLE TIMES, 1984
The Mima Mounds, 30 feet across and about 6 to 8 feet high, once covered thousands of acres on the prairies of Southwest Washington.

The Mima Mounds have been the focus of scientific study and campfire speculation since white settlers first set foot on the prairies that spread through what is now Pierce, Thurston and Lewis counties.

The mounds — neat, round bumps 30 feet across and about 6 to 8 feet high — once covered thousands of acres on the prairies, which Indians maintained by setting the land afire to keep back encroaching forests. Those forests have now largely covered the land that development and modern agriculture haven't already claimed.

Theories of the mounds' origin abound, and remain unproven. A popular idea is that the landscape graffiti was left by receding glaciers. Not-so-serious yarns include Paul Bunyan and his blue ox. One Indian legend says a great flood receded, leaving behind beached porpoises that became the mounds.

Storm says she leans more toward the geological explanations. But her research, which she is working into her Ph.D. dissertation, doesn't attempt to answer that question. Instead, as an ethnobiologist, she studies how the native people may have used the mounds to their advantage.

The Indians harvested many wild plants that sprouted on the prairies, perhaps none more important than the bulbs of the blue-flowering camas lily that still carpet the wavy landscape. The Indians ate the staple vegetable year-round, raw or baked, or pressed and preserved in flat cakes, which could be added to stews or used to sweeten boiled salmon.

Storm is attempting to prove that the repeated hills and dales of the Mima Mound prairies, long discounted on settlers' maps as second-rate growing land, created a uniquely varied ecosystem that allowed more diverse plants to grow and made for longer growing seasons.

To prove it, she has been performing tests on the mounds to determine whether they hold moisture and heat better than the troughs between them.

She hopes she may even be able to help show that the benefits of the mounds may have helped Indians settle in the area many thousands of years ago, and sustained them generation after generation.

Dave Peter, an ecologist for the U.S. Forest Service who studies the prairies, said it has long been observed that camas blooms at different times on top of the mounds than at the bottom.

"These ideas are pretty well accepted," he said.

"But she is among the vanguard of scientists who are actually documenting it and putting it into some formal record."

seattletimes.nwsource.com/html/localnews/2001859081_mima17m0.html
Link is dead. No archived version found.


They are beautifully regular but like patterned ground I had assumed these were well know (relic) features of a periglacial landscpae - like the more massive Pingus (and I'm not talking about enormous penguins).

Emps
 
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Whenever I think of massive penguins I think of the Mountains of Madness... But honestly, as much as I'd like to think the Mima Mounds were manmade I SERIOUSLY doubt they are. They just seem too "natural" to me.

On a related note, I was able to visit Cahokia Mounds over the weekend, which was the largest pre-colombian city in the US or Canada and includes one of the world's largest pyramids, as well as an enormous woodhenge and 70-something smaller mounds. Now that one is DEFINITELY manmade.
 
‘Digital gophers’ solve Mima mound mystery
By Rebecca Morelle
Science reporter, BBC World Service, San Francisco

Mima mounds

These Mima mounds in Washington State cover a huge area

The mystery of one of the strangest landscape features on the planet - Mima mounds - has been solved, scientists say.

These geological anomalies are circular hillocks that cover great swathes of land. But scientists have been puzzled about what causes them.

Now new research suggests that tiny burrowing animals are their architects.

The findings will be presented at the American Geophysical Union Fall Meeting in San Francisco.

Continue reading the main story

Start Quote

Until now, nobody really knew how they formed”

Dr Manny Gabet
San Jose State University
Mima mounds, which measure up to 2m (7ft) in height and 50m (160ft) in diameter, are found all around the world. However, they are most common in North America.

In some areas, they can number in their millions, stretching for many kilometres across the landscape.

Lead researcher Dr Manny Gabet, of San Jose State University, told BBC News: "The big mystery surrounding Mima mounds is that, until now, nobody really knew how they formed.

"Over the past couple of hundred years, people thought they might be Native American burial mounds, or they were caused by earthquakes or glaciers. Some people even suggested extraterrestrials."

Plains pocket gopher
It takes many generations of gophers hundreds of years to make a Mima mound
Now though, Dr Gabet says he is certain that gophers have created the mysterious mounds.

Using a computer program, the researchers analysed how the rodents move soil as they burrow.

They found that in areas prone to waterlogging, the gophers gradually shift tiny amounts of earth upwards to try to stay dry.

Over hundreds of years, though, as many generations of gophers repeat this process, these minute piles of soil grow into the large structures.

Dr Gabet said: "I developed 'digital gophers' and had them behave like they do in real life, and to my surprise Mima mounds just started to form in this virtual landscape.

Virtual mounds
Mima mounds created by "digital gophers" are almost identical to the real features
"The [computer] model results look so similar to the mounds in every way - not just the dimensions, but also the way they are packed and how many you get per area."

He added: "It replicates the real-life situation almost perfectly."

But gophers are only found in America, while Mima mounds are found in every continent apart from Antarctica.

However, Dr Gabet said that other subterranean mammals, such as moles, could be responsible for these.

"Mima mounds in the US are infested by gophers," he said.

"A good place to start would be to dig into these mounds [in other countries] and see what kind of critters are living inside of them."

http://www.bbc.co.uk/news/science-environment-25259133
 
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Here's some more general info about the Mimi Mounds. It's not clear how closely they're related to similar patterned ground / mound structures found elsewhere in North America and around the world.
Mima mounds ... are low, flattened, circular to oval, domelike, natural mounds that are composed of loose, unstratified, often gravelly sediment that is an overthickened A horizon. These mounds range in diameter from 3 to more than 50 m; in height 30 cm to greater than 2 m; and in density from several to greater than 50 mounds per hectare, at times forming conspicuous natural patterns. Mima mounds can be seen at the Mima Mounds Natural Area Preservein Washington state.

"Mima" is a name derived from a Native American language meaning "a little further along" or "downstream".

Theories for the origin of Mima mounds include burrowing by pocket gophers; accumulation of wind-blown (aeolian) sediments around vegetation to form coppice dunes or nebkhas; seismic ground shaking by major earthquakes, though none have been observed to form Mima mounds; and shrinking and swelling of clays in hog-wallow or gilgai landforms. ...

https://en.wikipedia.org/wiki/Mima_mounds
 
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