My first stop (when I FINALLY got to it) was Obsidian Butte.
Obsidian Butte is one of five lava domes in the Salton Sea Geothermal Field.
The part of it that is exposed above ground is about 90 feet tall, but it goes much, much deeper underground.
MORE INFO HERE FOR GEO-GEEKS.
Here (left) I am parked part way up it.
The thing that drew me to Obsidian Butte was the obsidian–and the pumice.
When I read that there were obsidian and pumice at the side I had to go
there. I mean, obsidian and pumice are two of my favorite igneous rocks!
(Incidentally, 10 points to anyone who can remember a major sci-fi character whose computer password was "Obsidian.")
They’re both so cool: Obsidian because it is black and shiny and glass-like and pumice because it is so bubbly and light weight.
I read online that one guy who visited the site took home a 400-lb.
obsidian BOULDER, and so I knew that I had to go someone that had
obsidian boulders.
I didn’t take home any boulders, but I did take home these two rocks
(plus a few others). I made sure I got both some obsidian and some
pumice.
I was just struck by the fact of them occurring together. I had no idea they did that.
I was also surprised by the fact that the ground has this unusal
CRUNCHY texture to it. It’s not like ordinary dirt. I think it’s at
least partly because of the pumice that’s part of the dirt. It sure
feels weird as you walk along and the ground is flattening under your
shoes and going CRUNCH, CRUNCH, CRUNCH.
I was amazed at some of the things that grew on Obsidian Butte. The environment out here is really barren and salty and alkali. I’m guessing that not too many species of plant can survive in it. But some can, like this one with jet white leaves:
There was lots of this stuff all over Obsidian Butte. But not everything survived there:
Here’s some more of that harsh, alkali environment:
After I left the site, I found the largest obsidian boulder of all (at least of the ones I saw). It wasn’t at Obsidian Butte, but it was on a road leaving the site and I’m sure it weighs a LOT more that 400 lbs. (Note my boot for a scale of reference):
NEXT: Mud volcanoes!
this is really cool, but i almost prefer the tar pits. besides, it’s really fun to be able to say “I went to the La brea tar pits” which translates into “I went to the the tar tar pits” when you get the whole thing in english.
Growing up my dad would take us to places like this only in WA state – ghost towns, dams, caves, panning for gold, etc. fun stuff.
Like a rock, I was strong as I could be
Like a rock, nothin’ ever got to me
Like a rock, I was something to see
Like a rock, oh like a rock!
Geologist speaking. Actually pumice and obsidian usually occur together. The only difference between them is the amount of trapped air. Often you can see alternating bands of obsidian and pumice. Current thinking is that the banding is caused by localized shear as the magma is pushed up and out of the volcano. I always enjoy seeing the variation in vesicle (bubble) sizes in pumice. Sometimes the vesicles are elongated due to strain and flow.