|We unexpectedly happened upon Castle Geyser as it was erupting|
During the busy season here I don’t spent very much time in the Upper Geyser Basin. The summer crowds swarming around Old Faithful can be overwhelming and so I tend to avoid the place. Surprisingly, the Friday before Labor Day turned out to be an exceptionally fine time to check out thermal features where boiling water and superheated steam shoot skyward. Timing seems to be everything, even on a major US holiday weekend – during the mid morning and early afternoon hours there were few other folks milling about.
Very few geysers in Yellowstone are actually predictable – less than a dozen out of nearly 500. A majority of the predictable ones are in the Upper Geyser Basin, the home of Old Faithful whose eruptions do occur quite faithfully around every 90 minutes ± 10 minutes.
There is so much more to experience at the Upper Geyser Basin than just Old Faithful, though. And so, with a list of prediction times for three of “the big ones” –Daisy, Grand, and Riverside – in our hot little hands, fellow geyser gazer CW and I were on a mission this sunny afternoon to witness as many eruptions as we had the times for, and a few that we didn’t. We had all day, after all.
Castle Geyser was one prediction we had missed for some reason. I can’t remember why we neglected to note the time of Castle. Perhaps we neglected it since it erupts at an interval of 13 hours ± 1 hour and so we figured we wouldn’t see it anyway. Perhaps we neglected it since we thought a minor eruption had occurred recently and so there wouldn’t be another prediction for a day or so.
But none of that mattered in the end.
Because as CW and I chatted our way towards a rendezvous with Daisy we felt compelled to stop, mesmerized, while Castle blew in a major eruption for at least 20 minutes, boiling water propelled out of the ground by superheated steam, ejected upwards along the unseen pathway of its own underground plumbing system of fractures and fissures.
|Castle Geyser mound of geyserite|
With such a large geyserite cone, or mound, how old could a geyser like Castle be? I’ve heard that one way of dating such a cone would be to carbon date any wood fragments that might be found within the mound. According to “The Geysers of Yellowstone” Castle may have formed as early as 10,400 years ago but most likely in less than 8800 years. It is in all likelihood the most massive free–standing mound of geyserite anywhere. It's eruption column can reach heights of around 80 feet.
And this is just the first geyser we stumbled upon that day. Daisy and Riverside would soon be erupting and we simply had to be there.
Now all I need to do is figure out how to add geyser videos to these blog posts. Stay tuned!