We
started with the lower terrace trails at Devil's Thumb and Palette Spring.
Devil's Thumb is the pointy thing, Palette spring is the hillside covered
in algae and hot water. A ranger once told me that there used to
be more features named after the devil or hell in the early days of the
park, but that the names were changed on many of them. Unfortunate,
but probably the names were getting too repetitious. I assume that
Devil's Thumb is a dormant hot spring cone along the lines of Liberty
Cap or Orange Mound
Spring , one where there was a small but steady flow of water over
the years that built up a steep sided cone. Remember the browser's
back button for these links to get back here. Palette Spring is kind
of cool too, you can get really close to it. In fact you could walk
through it as the water was flowing over the paved trail in spots, trying
to cover it with Travertine.
Cleopatra
Terrace. The way I understand it, this feature was one of the stars
at Mammoth in the early part of the 20th century, but was inactive in recent
decades. It was used in guide pamphlets as an example of how activity
at Mammoth shifts frequently. It has now rejuvenated. Angel
Terrace farther down the page has a similar story.
This
is a pool at the top of Canary Spring, which is on the Upper Terrace Drive,
a one way road well worth taking. Because at Mammoth you are frequently
looking at a big mound of hot spring deposits from the bottom, sometimes
it is hard to see where the water actually comes out of the ground.
I had a Japanese gentleman ask me this day while we were lower down the
hillside where the "hot springs" were. I was puzzled at first as
we were surrounded by hot springs. Then I assumed he wanted to see
the actual pools, so I told him to climb or drive to this area. Then
he was all happy. I don't know if he climbed or drove.
Another
pool at the top of Canary Spring. This one is covered with an unusual
formation called Travertine Ice. Travertine is a rock that is formed
when springs deposit calcium carbonate (the same mineral that makes up
limestone). Mammoth is unusual in that the hot springs here deposit
travertine instead of geyserite (a type of silica) like most of Yellowstone's
hot springs. This is because the hot water flows through beds of
limestone here. It is hot and slightly acid because of the carbon
dioxide dissolved in it, and dissolves lots of limestone, tons of it per
day. After the water reaches the surface it both cools and becomes
less acidic as the carbon dioxide escapes, and the dissolved limestone
gets deposited as travertine. At Mammoth's terraces the travertine
is usually deposited most rapidly at the edges of the pools, where the
water flowing over the edge cools and looses the carbon dioxide the quickest,
which builds up the edges faster than the bottom of the pool and frequently
leads to a situation where there are a series of pools that do look sort
of like a terraced hillside. Every now and then for reasons I am
not sure of the travertine is deposited on the surface of the pool like
this. I do not know why it does not sink. But, it does look
a lot like ice.
Here
a big stream of hot water from Canary Spring is rapidly depositing Travertine,
and burying trees. Mammoth's hot springs can deposit a few feet of
travertine in one year, while a typical geyser cone may grow at the rate
of an inch a century.
More
of Canary's runoff stream. The frilly formation in the lower left
looked kind of cool, looked like stringy colonies of bacteria I have seen
in other hot springs. Scientists are just beginning to understand
how the bacteria and algae in hot springs affect the way they deposit minerals.
The
very edge of Canary's runoff stream, with some grass getting incorporated
into the travertine.
This
is angel Terrace, at the end of the upper terrace drive.
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