Yellowstone--West Thumb Geyser Basin

Wow!  What Color!



Our last morning at Yellowstone brought us to the South entrance.  This would be the way we would leave the Park.  But before heading south, we veered slightly to the East to the West Thumb Geyser Basin.  It is adjacent to the Yellowstone Lake.  There are three tiny geysers/springs that are IN the lake...The Big Cone, The Fishing Cone and The Lakeshore Geyser.  And Lakeside Spring.  There are three other geysers, some fumaroles, several springs and pools and the Thumb Paint Pots.  A potion of the boardwalk trail is 1/4 mile.  The longer loop is 1/2 mile.  Yellowstone Lake is the largest lake at a high elevation (over 7,700 feet).  The Lake is approximately 14 x 20 miles with a shoreline of 141 miles.  The maximum depth is 410 feet.  Despite the release of thermal hot water, the lake's average summer temperature is 45 degrees (F).  Although we did not see them, it is a favorite place for trumpeter swans and moose.

Information provided by pamphlets published by Yellowstone Association and "Oh, Ranger Yellowstone National Park."

All photos by "Molly" Marston

 



Canada Geese checking out breakfast

Yum!  A hot breakfast

 

 

 

 



Black Pool
This was named as it was black at one time as it had a lower
water temperature which allowed heat-loving dark green and brown
thermophiles (microorganisms) causing it to appear like a black mat. 
In 1991 the water temperature rose, killing the organisms.  It erupted
several during that year.  It is now a beautiful, quiet bluish pool. 

Near Hillside Geyser



 
 
 

Lakeshore Geyser

Big Cone (in the lake)

Fishing Cone

Often submerged in lake.  Water level drops in late summer

allowing cone to become visible.    Its name comes from the

mountain man legend of catching a trout in the lake, swinging

the pole around, dip it into the boiling water in the pool.  The

fish would be cooked without taking it off the line.  Fishing is

no longer allowed in/around this cone.  Many injuries from

straddling the boiling water and damage to the cone by feet

led to this change.





Active boiling mud pot

Mudpots appear to be a field of miniature volcanoes

approximately 3-4 feet high, steam curling from their

chimneys.  The mud swirls and bubbles and can be

thrown up to 25 feet.  Often looks like a potter's shed.

 

Mudspots differ from other thermal features.  The water

 is much more acidic, dissolving surrounding rock to clay mud. 

Precipitation and ground water levels can vary the consistency.