Wednesday, June 3, 2009

Walking in a Volcano

We've visited the geysers and the canyon of Yellowstone. Now it was on to Yellowstone Lake and meadows.

This cow moose greeted us and several other visitors soon after we entered the East Gate. We have such poor luck in seeing wildlife, so this was a rarity to be enjoyed.

This meadow area in Hayden Valley was crossed by Alum Creek.

Hayden Valley is a former lakebed and usually a good area for viewing wildlife. We saw one buffalo, and even with binoculars, it seemed very small.

On the southern border of the Hayden Valley are some dramatic displays. With its aromatic signature, Sulphur Caldron bubbles away. Microorganisms eat the sulfur and create sulfuric acid. As it evaporates, it becomes hydrogen sulfide gas. It is among the most acidic springs in the park with a pH of 1.3.

Crossing the road brings us to Mud Volcano. Sulfur and bacteria basically eat up surroundng rock, creating mud. The yellow is sulfur.

Dragon's Mouth Spring is accurately named. This is a spring that fills a cave in the side of a hill. The gases that rise to the surface cause the water to splash back and forth against the three cave walls. This splashing of water resembles a tongue lashing out. The steam seems to be coming out of the nostrils of the dragon.

Covering 136 square miles, Yellowstone Lake has 110 miles of shoreline. Situated at an elevation of 7,733 feet, the lake remains cold the year-round, with an average temperature of 41°F.

Yellowstone Lake is the largest natural freshwater lake in the United States that is above 7,000 feet and is one of the largest such lakes in the world.

Yellowstone Lake has the largest population of wild cutthroat trout in North America. Just how these Pacific Ocean cutthroat got trapped in a lake that drains to the Atlantic Ocean puzzled experts for years. There is now a theory that Yellowstone Lake once drained to the Pacific Ocean and that fish could pass across the Continental Divide at Two Ocean Pass.

In recent memory, the event which has had the greatest effect on Yellowstone National Park is undoubtedly the great fires of 1988. We have included this picture of the recovery.

We saw several buffalo on our recent visit to the park. This one seemed particularly willing to pose for this photo.

While enjoying the beautiful and varied scenery of Yellowstone, we still realized that we were walking in a caldera, a large basin-shaped volcanic depressions more or less circular in form. Caldera eruptions on the Yellowstone scale have a world wide frequency of perhaps once every hundred thousand years.

The volume of volcanic rock produced by the first Yellowstone caldera eruption was about 600 cubic miles--about 2,400 times as much as Mount St. Helen's, an almost incomprehensible figure. One more statistic: Yellowstone ash is found in Ventura, California to the west and in Iowa to the east. It is likely the earth has seldom in its long history experienced caldera explosions on the scale of those that created Yellowstone.

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