I already gave you a little sneak peek the other week when I posted this first picture as my ‘photo of the week’. My supervisor had sent me into the field for a week and me and my co-workers work by the principle “work hard, play hard”. We put in some long-hour days, but that also left us with some extra time to explore the area in which our field work was happening this time. We worked on the east side of the Sierra Nevada and had the opportunity to go visit Devils Postpile National Monument.
I do not really have an actual bucket list of places that I want to visit (maybe I should start one?), but if I had one, Devils Postpile would definitely have been on the list! I’ve seen a similar (much smaller, mind you!) formation in Germany before when I was on a field excursion with my geology class way back when. I remember it well and always wanted to see other formations like that around the world.
I just love how impressive the scale of this thing is! How beautiful it is! Places like this make me fall in love with my field of work all over again. I am simply in awe of Mother Nature!
Devils Postpile is the result of volcanic activity in the area and the name refers to a dark cliff of columnar basalt. Devils Postpile started out as a lava lake. About 100,000 years ago, hot basaltic lava came to the surface and formed into a lake. As the lava flow ceased, the lake began cooling into solid rock and started to contract. The cooling process developed cracks, also called joints, that reached deep into the formation and the big network of fractures results in the formation of vertical, (mostly) hexagonal columns.
Devils Postpile used to be much taller than what we can see today. Powerful erosive forces have been at work during the last 80,000 to 100,000 years carving, shaping and demolishing remnants of the lava flow.
The columns average 2 feet (0.61 m) in diameter, the largest being 3.5 feet (1.1 m), and many are up to 60 feet (18 m) long. f the lava had cooled perfectly evenly, all of the columns would be expected to be hexagonal, but some of the columns have different polygonal cross-sections due to variations in cooling. A survey of 400 of the Postpile’s columns found that 44.5% were 6-sided, 37.5% 5-sided, 9.5% 4-sided, 8.0% 7-sided, and 0.5% 3-sided.
Interesting facts! Sorry for geeking out here a little bit! Go read the survey if you’re interested to learn more about the forming of these columns! (Highly recommend!)
We took a little hike up to the top of the formation a little later and were able to look at the cross-section of those huge columns. A glacier removed much of this mass of rock and left a polished surface on top of the hexagonal columns with very noticeable glacial striations and glacial polish.
Isn’t this amazing? People pay a lot of money for hexagonal tiles in their backyards and here it’s occurring naturally! And look at the diameter of these!
I am really thankful that I had the opportunity to check this place of my (non-existent) bucket list.
Have you been to Devils Postpile and/or the Eastern Sierra Nevada? It’s beautiful out there! I highly recommend you go visit!