Tag Archives: geology

Walden Pond is temporary (Walden 130)

Walden Pond in autumn. Wikimedia Commons

Walden Pond in autumn. Wikimedia Commons

Just one more thought about the origin of Walden Pond. After discussing local legends, Thoreau writes, “It is very certain, at any rate, that once there was no pond here, and now there is one…” Continue reading

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The hole in the bottom of Walden Pond (Walden 129)

Thoreau's map of his soundings of Walden Pond. Wikimedia Commons

Thoreau’s map of his soundings of Walden Pond. Wikimedia Commons

There is something deeply strange about Walden Pond. “The pond rises and falls,” Thoreau wrote, “but whether regularly or not, and within what period, nobody knows, though, as usual, many pretend to know.”

What’s weird is that the water level doesn’t seem to vary with local rainfall. It rises and falls for no apparent reason. Henry said “I can remember when it was a foot or two lower, and also when it was at least five feet higher, than when I lived by it.”

The Concord Magazine reprinted a fascinating 1971 article by Eugene Walker, a geologist and local resident. Walker writes, “Tales are told around town of the hole in the bottom of and the stream that comes through it, connected perhaps to a river that is rumored to run underground from somewhere in the White Mountains, perhaps Lake Winnipesaukee, southward to Cape Cod.”

But the truth, Walker explains, is that the pond’s water level varies exactly with the water table in the sand and gravel that surrounds the lake. In other words the lake bed is apparently porous: Continue reading

Temporary mountains

A big part of both creativity and curiosity is the act of looking at familiar things in new ways. Consider time, for instance. Or better yet, a pile of snow.

Where I live, five hundred miles east of the Rockies, one can be forgiven for seeing mountains where there are none. Right now there’s one beside my driveway. It warmed up today and the pile is only about two feet high now, a shadow of its former glory. This tiny mountain has been here all winter. It shrinks as it melts a little, then grows whenever I scoop fresh snow onto it.

Mount Massive in the Sawatch Range of Colorado, via Wikimedia Commons. I wrote this little essay a few years ago, during a snowier winter than the one we're having this year in the central US, and I neglected to take a comparative photo of Mt. Not-So-Massive beside my driveway. Use your imagination.

Mount Massive in the Sawatch Range of Colorado, via Wikimedia Commons. I wrote this little essay a few years ago, during a snowier winter than the one the central US is having this year, and I neglected to take a comparative photo of Mt. Not-So-Massive beside my driveway. Use your imagination.

It’s when the snow grows old and weathered that it most resembles a genuine mountain. The Rockies aren’t going to melt into a puddle under a warm sun, but the forces that sculpt mountains are in some ways similar to those that sculpt snow banks. The pull of gravity and the slow trickle of water give the snowbank something of a mountain’s familiar but ever-unique shape.

What is different is the timeline. Continue reading