Learn paradox of Red Butte, Aspen’s other geologic wonders
July 16, 2002
While many people like to ponder how Aspen has changed in the last 50, 25 or even two years, Garry Zabel likes to go back a bit further, at least 10,000 years or so.
Zabel, a geology professor at Colorado Mountain College for 25 years, has studied how the movement and melting of glaciers helped carve out the landforms around Aspen.
Some geologists believe, he said, that the Aspen area was once under a slab of ice 1,000 feet thick. Glaciers expanded and retreated numerous times starting about 2 million years ago and didn’t disappear until about 10,000 years ago, he said.
The Grottos area east of Aspen is one of the best places in the valley to see the grooves that relatively recent glaciers carved into ancient rock, Zabel said.
All that pulverizing action and melting wiped out much evidence of early glaciation, but the top of Red Mountain contains deposit material from long-ago periods, even though it’s 2,000 feet above the valley floor, he noted.
Zabel will share the knowledge he’s gained in a geology field trip sponsored this week by the Basalt Recreation Department. Participants will get a primer at 6 p.m. Thursday, July 18, in Basalt Town Hall, then hit the road for a geologic tour Saturday, July 20, starting at 9 a.m. at the town hall. Transportation in vans will be provided.
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The tour will feature Mount Sopris first, then work its way toward the Grottos, stopping several times in between to observe some of the more outstanding geologic features.
Zabel said he has always been fascinated with Sopris.
“Most people think it’s a volcano,” he said. In reality it’s a dome mountain that was created by the intrusion of molten rock, Zabel said. The molten rock never penetrated to the surface.
From Sopris, the tour will work its way upvalley and study the evidence that underground forces and glaciers left behind. Participants will learn why Red Butte outside of Aspen is considered such a geologic oddity. By the end of the class, they will be able to answer why Mount Daly has such a distinctive stripe.
Zabel said everything we can see now was created by action at great depths below the surface or below the sea level. The terrain that eventually became Independence Pass was subjected to uplifts and folding that built it up 30 million to 70 million years ago.
The classic U-shaped valleys, such as Maroon and Castle, were carved out 3 million years ago by glaciers. Massive melting created V-shaped terrain farther downvalley.
“What interests me the most is getting a greater understanding of our surroundings,” Zabel said.
The cost of the geology tour is $25. At least eight people must sign up for it to be held. Participants should bring a lunch as well as shoes and clothing appropriate for short hikes.
Reservations must be made by Thursday at noon by calling Dorothy Howard at 927-8214.
[Scott Condon’s e-mail address is firstname.lastname@example.org.]