Alaska Journal #32: Denali National Park, Part Three

"Approaching Polychrome Pass, the geologic form beneath Denali's landscape tapestry is revealed.  Volcanic outcroppings hug the road to the north and mountains rise high to the south.  Glaciers glimmer in the distance and valleys sweep their ancient paths."

"A half-billion years ago, the land around Denali was an ocean floor.  Today it is hundreds of miles from the coast.  Mixed in are geologic fragments of diverse types, dating from different eras.  It is a patchwork formed through colossal movements that shape it still."

"In 1980, a geologist proposed that the entire western edge of North America had been shuffled much more than previously suspected.  Evidently, landmasses, called 'terranes,' had been carried toward Alaska by the conveyor-belt-like movement of the Pacific Plate."

Well, what have we here?

These two grizzly bears appear to be "wrestling."

They "wrestled" for quite some time without tiring.

The darker brown bear was a bit of a bully, never letting the lighter brown bear out of this hold.

With no referees to break them up, they "wrestled" on and on.

There probably isn't a whole lot of other entertainment for bears other than "wrestling."

Our tour guide really, really enjoyed watching the "wrestling" match.  He was laughing his head off.  In the 30 years he'd been a driver/guide, he'd never seen two bears having so much fun.  We lingered at the side of the park road for nearly the entire "wrestling match."

Finally, we slowly began to drive away.

There were, after all, other sights that demanded attention.

The textures and rich colors are truly engaging.

One more look back at the "wrestling" bears.  I think they'll set a record for length of match.  

Back to geology.  "This enormous plate grinds northward until it collides with the continental North American Plate.  There, in the earthquake-rattled subduction zone, the Pacific Plate slides deep into the earth.  But before it slides, it drops off any lighter landmasses picked up along the way.  Long ago, these mismatched landmasses, reaching the end of their free ride, were scraped off and stitched onto Alaska."

"Continued Pacific Plate movements have further buckled the terrane crazy quilt.  For example, the Outer Range, which rises just north of the park road, was created by tectonic lifting about five to six million years ago.  Even today, the northward pressure of the Pacific Plate lifts Mount McKinley, at 20,320 feet North America's highest peak, still higher.  The creep is imperceptible, a rate of about one inch per 25 years."

"The terrane theory helps explain why southern Alaska's rocks are, in the words of writer Michael Collier in The Geology of Denali National Park and Preserve, 'a tangled mesh of differing types of rock, interwoven faults and folds.  Rocks at Denali seem to come and go, to change from one type to another within just a few feet.'"  

"Plate tectonics are only part of what makes Denali geology so interesting.  Heat and ice, in the forms of volcanoes and glaciers, have added even more patterns, colors, and shapes to the geologic patchwork."

"The bright colors of Polychrome Pass were created by magma, which welled up and spilled over older sedimentary rock layers.  Those ancient sedimentary rocks, 100 million years old, can be seen in Igloo Canyon, along Polychrome Pass, just after the rest top." 

"The thick blanket of volcanic debris spewed 50 to 60 million years ago appears as colorful bands of brown, yellow, tan, white, orange and purple at the Pass.  They include basalt, andesite, and thyolite." 

"Glaciers have scraped and spilled through most of the park in successive Ice-Age pulses, carving out U-shaped valleys before retreating to their high, cold birthing places.  After the most recent episode, which ended less than 10,000 years ago, the largest glaciers shrank back to their icy cradles in the Alaska Range, south of the park road.  There they creak, growl, and drip, feeding silty rivers that course through the park's many valleys."

We stopped to enjoy this mother bear.

Her cubs are on the right side of this photo.

It's surely fun to see these animals in their natural habitat, going about their lives.

Well....

"The Athabaskans have their own explanations for how the landscape, including Denali, or the 'High One' was shaped.  Central to the sacred story is Raven.

The Raven, incarnated as a young man, had paddled his canoe across a great body of water to ask a woman to marry him.  She refused to be his wife, so he made her sink into the mud and disappear, and then he began paddling back home.  The woman's mother kept two brown bears, and in her anger she told them to drown the young man.  They dug furiously at the lake's edge, making huge waves everywhere on the water.  But Raven calmed a narrow path before him and paddled on.

Eventually, he became exhausted, so he threw a harpoon that struck the crest of a wave.  At that moment he fainted from the intensity of this concentration, and when he awoke a forested land had replaced the water.  He saw that the first wave his harpoon struck had become a small mountain.  Then it had glanced off, eventually striking a huge wave that solidified into another mountain--the one now called Deenaalee, or Mount McKinley."  --Paraphrased from Jette 1908:312-13, in Make Prayers to the Raven

"'National parks are paradoxical places, they offer freedom, yet require restraint.  They are best explored deeply, yet lightly.  they demand new sensibilities if we are to leave them as we found them, unimpaired....'"
--Kim Heacox
National Parks Magazine, 1999

"Like marbles dropped by giants who abandoned their game eons ago, solitary boulders can be found in both taiga and tundra.  These glacial erratics, as they are called, were deposited by retreating rivers of ice."

I hope you enjoy both the pictures and the narration.  The material in quotation marks is from Denali:  A Living Tapestry, A Wilderness Tour Companion. 

If you don't enjoy all the captions, the pictures may be all you need to enjoy the state of Alaska.

Some day soon, Lon and I will have to make decisions as to which photos we want to enlarge and display in our home.  The nice thing is that we can put a few up and then after a while, replace them with different ones as we please. 

Denali National Park, Part Four is coming up.