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July 22, 2014


Glaciers and the Art of Change -part 1

by Herb Saperstone
Lateral Moraine (forested ridge) in Rocky Mountain National  Park

Pinedale-age (Ice Age) Lateral Moraine (forested ridge) in Rocky Mountain National Park

What I love about geology is imagining  changes in our earth through impossibly vast periods of time.  Some things are difficult if not outright impossible to study directly (the nature of the earth’s interior) but landscsapes afford an easier path for us curious souls.  In the case of  river or glacial geomorphology (geomorphology is the study of landforms and the processes that form them), the evidence for landscape evolution is quite accessible.  Having visited Moraine Park in Rocky Mountain National Park many times, I was always amazed and even somewhat skeptical that those heavily forested ridges are actually enormous Ice-Age piles of chaotically arranged gravel and boulders- better known as lateral moraines. Only after seeing active glaciers and their companion moraines, can one truly see how they form as rocky rubble from valley walls shoved into long ridges against the steep sides of the ice-filled valley.


Actively forming lateral moraine near Kennecott Mine along the Root Glacier in the Wrangell-St Elias National Park.


Aerial view of Root Glacier, Wrangell-Elias National Park. The gray ridges flanking the glacier are lateral moraines

On a recent trip  to Alaska, Jessica and I had the good fortune to visit glaciers- a lot of glaciers as we love to hike and explore new areas wherever we can.  If you examine the images closely, you can see the obvious  relationship between lateral moraines and their glaciers– now– today– in the present –Wow. You can even hear the rocks sliding and moving as the glacier creeps downhill in an arguably -not so glacial speed.  That’s another story of course. You see, these moraines are fresh and naked of vegetation, so from the air or from the ground, their steep gray ridges are easy to spot.  Jessica, who has learned to endure my commentaries like this for decades easily notices these features in Rocky Mountain National Park. We may not be able to travel in time, but we can travel in space to make these connections real and truly understand all dimensions of change on our planet.


Jessica observing the receding Exit Glacier at Kenai Fjords National Park


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1 Comment Post a comment
  1. Feb 3 2020

    Nice Post


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