Yellowstone-the Caldera (06-19-12)

640,000 years ago, a volcano erupted in the area that is now home to Yellowstone National Park.  What was left behind was a Caldera-by definition, a basin like depression resulting from the explosion or collapse of the center of a volcano. In this particular case, the volcanic activity has never completely subsided. So, Yellowstone sits on a hot spot of volcanic activity, with hot magma just below the surface, providing the basis for the hydrothermal activity that this area is known for. 
   There are several puzzle pieces that are required in order for these features to exist.  The first-heat- is provided by the magma.  The second-water-is provided by the vast amounts of rain and snow that this area receives and the third-underground “plumbing”- naturally exists here in the form of  cracks in the rock, and constantly changes due to the large amount of earthquakes that take place here. The Yellowstone area has more earthquakes per year than anywhere in North America except California.  Most are small enough that they can’t be felt.

What form the heated water takes when it reaches the surface depends on what is directly under it. There are four basic hydrothermal  features.  Hot Springs are the most common, and are created when the “plumbing” under the ground is not constricted, allowing the heated water to rise freely to the surface.  The steam vents (fumaroles) are the hottest surface feature but contain very little water- hence the steam. Mudpots are very acidic, also with very little water.  The combination of gasses and microorganisms create mud/clay.

 

The fourth kind, geysers, are perhaps the most well known. Geysers are created when there is a constriction in the underground plumbing, so the boiling water stays below the constriction until so much pressure is built up that it “blows”.  Most of us are familiar with “Old Faithful”- the Yellowstone Geyser that erupts frequently, and with great predictability. When Old Faithful blows, it spews 3,700, to 8,400 gallons of boiling water into the air over a span of 1-5 minutes. Every 60-90 minutes the process is repeated, making it the geyser with the most frequent eruptions.  There are many other geysers here, some spew quite a bit taller than Old Faithful.  Yellowstone has the highest concentration of geysers in the world.

This one, Sapphire Pool, is my absolute favorite hot spring in the park.  It looks so inviting it makes me want to jump right in. Of course, that wouldn’t be a good idea.

The hot springs are “color coded”.  The different colors that are created, from the beautiful blues to the bright yellows, are actually micro organisms.  Different organisms survive in different water temperatures.  The yellow organisms live in water that is about 120 degrees.  The beautiful white and blue organisms live in water that is about 180 degrees.

This bright yellow river of water comes from Sapphire Pool.

Everywhere you go in the Geyser Basin area of the park, there are beautiful pools, (and some not so beautiful ones too) with steam rising from them. 

Most of the trails in the area are boardwalks.  There are several reasons for that.  First, the ecosystem is very fragile, and with millions of visitors a year, would be easily destroyed.  But also, with boiling water just below the surface, it’s impossible to tell which areas are solid ground and which would collapse when walked on.  One section  had to be closed once because the ground temperature almost reached the boiling point.





An administrative note:  we have no cell service or internet anywhere near the campground we are staying in. I am hoping I will be able to post this as we drive through an area that does. I’ve made the pictures smaller so they’ll hopefully upload easier. We also have no TV, so we’ll see who goes stir crazy first- me or Paul! 24 days suddenly seems like a long time!