Alaska sand dunes recall the state’s ancient geological past

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Sitting at a window seat on a latest flight from Seattle to Fairbanks, I regarded down on Alaska from 35,000 toes.

There was my dwelling river, the Tanana, flowing grey and braided from close to the Canada border. The Alaska Freeway adopted the river’s curves.

Close to the city of Tok, a wedge of sharp hills regarded completely different from the encircling, extra rounded ones. Alaska Freeway 5 — the Taylor Freeway — lower by way of the unusual bumps.

The landform, accentuated by the glow of fall foliage, was a big sand dune advanced. Once you drive the 160-mile Taylor Freeway to Eagle or use it to get to Dawson Metropolis within the Yukon, you discover a highway lower the place individuals through the years have set rocks within the sand to spell out their names.

I despatched a window-seat photograph of the scene to Dan Mann, a College of Alaska Fairbanks scientist. He mentioned the Taylor Freeway runs by way of sand dunes that shaped a very long time in the past.

“You may see from their orientation that they have been fed by sand blowing northwards off a barren and expanded Tanana (River) floodplain.

“The sand was coming from glaciers within the Wrangell and Nutzotin mountains to the south and east. There are smaller patches of dune all alongside the Tanana River as much as the Canada border, and simply throughout the border there is a gigantic dune subject that I feel is way older.”

The vegetated dune on the Taylor Freeway flip is small in comparison with some in Alaska that make you’re feeling you might be within the Sahara, apart from the moose tracks.

The Nogahabara Sand Dunes — west of the Koyukuk River and the villages of Hughes and Huslia — are a whitish splotch on the face of Alaska that covers 26 sq. miles.

Even bigger and extra visited for his or her proximity to the Kobuk River in northwest Alaska are the Nice Kobuk Sand Dunes, 38 sq. miles. Not removed from them are the Little Kobuk Sand Dunes, 5 sq. miles. Just like the Nogahabara dunes, each units of Kobuk dunes are energetic, nonetheless migrating through the wind at speeds as much as three toes per 12 months. This motion smothers tree seedlings earlier than they’ll make a go of it.

In a 1990 paper, Peter Lea and Chris Waythomas mapped out the energetic and inactive sand our bodies in Alaska. Sand is nearly all over the place that glaciers weren’t over the last ice age, however many of the dunes are actually lined with bushes and shrubs. Giant sand deposits stay on Alaska’s North Slope, the Seward Peninsula and all by way of Southwest and Inside Alaska, the place the Taylor Freeway dune is positioned.

In a research of the Nogahabara dunes, scientists together with Mann wrote that one of many energetic dunes’ values is continuous to host vegetation like an Asian sedge which can be relics from the time of the Bering Land Bridge. The Nogahabara can also be dwelling to the sandy tiger beetle and the Alaska tiny shrew, that are each discovered virtually nowhere else within the state.

Sand deposits all over the place in Alaska harken again to a time 1000’s of years in the past when large winds blasted positive particles of glacier-ground mountain a great distance. It should have been an disagreeable time to be strolling round Alaska, however scientists like Mann are fascinated with what it left behind.

“Alaska’s sand seas are tremendous fascinating and poorly understood,” Mann mentioned.