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March 18, 2020

Heading farther north than she has ever been

On the cusp of Interior Alaska’s springtime, Melinda Webster will not experience it this year. She’ll miss most of summer, too. Webster will soon head north of Earth’s land masses, to spend the next half year cradled in ice.

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March 17, 2020

It’s a great time to take a virtual field trip

Spring field trips are canceled, which makes it really hard to get students charged up about Earth sciences. Here’s a selection of virtual field trips that can’t replace the real thing, but may help students not lose interest, and may even whet their appetites for the day we can venture out again, field notebooks and rock hammers in hand.

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March 12, 2020

The recent fall of the upper Yukon River

While skiing with two friends on the frozen Yukon River a few weeks ago, I visited the eight people who live between the towns of Eagle and Circle, which are 160 river miles apart. The adults in those three households all shared the same observation: The Yukon River’s average level has dropped recently. They all mentioned “river piracy” that happened in an unseen high valley, 500 miles away, as a probable cause.

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March 10, 2020

A sandbox model without fault(s)?

Fold-thrust belts (both real and model, like this one) develop fault and fold patterns that reflect the properties of the rock (or sand-like materials) being deformed. The model section shown (shown here) is interesting because it results from shortening a granular layer sequence by 50% and does not show any major thrust fault structures that cut through all of the layers…

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March 9, 2020

‘Remarkable groove’ slides gold into Alaska

In the 160 miles between the towns of Eagle and Circle, a half-dozen gold-mining settlements — most of them ghosted out — were on the south bank of the Yukon River. Not one was on the north side. That seemed like more than a coincidence.

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February 27, 2020

Where did that boulder come from? A LiDAR perspective on a large Appalachian rockfall

I have always wondered about the possibility of finding the specific outcrop source of large boulders, which is very difficult in the field due to vegetation and continued evolution of the cliff line after a boulder falls off and makes its way downhill. Using LiDAR-derived hillshade imagery of a portion of the Blue Ridge Escarpment in western North Carolina, I recently came across a particularly large boulder that appears to be traceable to a scar on cliffs hundreds of feet further up the slope.

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February 25, 2020

Winter journey along the Yukon River

We just skied 100 miles of the frozen Yukon River, two friends and I, until it got too cold for our skis to glide, and we flew back to Fairbanks on a plane that landed on both skis and wheels.

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February 17, 2020

Outcrop patterns in a fold-thrust belt analog model, round 1

The model shown here did not work out as planned because I shortened it too much, but the overall appearance is still cool and reflects local variations in the layer pack. In real fold-thrust belts, the local or regional variations in folding and faulting style also reflect the details of the layer sequence being folded and faulted, among many other conditions.

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February 10, 2020

The Pigeon River is perched, which is geologically bad news for it

At Canton, North Carolina, the headwaters of Hominy Creek, a French Broad River tributary, are VERY close to capturing the Pigeon River. In human terms, this is still probably a long way off, but it is most certainly geologically “imminent.”

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February 3, 2020

The mountain that has it all (at least it did in the pick-and-shovel days)

Back in 1830, The Catawba Iron and Coal Company got an outrageous deal on a plot of land at the foot of North Mountain in western Botetourt County, Virginia. Within about 1 square miles, coal, iron ore (oxide), and high-purity limestone could be mined, and thick layers of quartz pebble conglomerate could be quarried for much sought-after millstones.

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