29 September 2010
Guess this means it’s columnar jointing week
Posted by Jessica Ball
Well, since everyone else is getting in on the columnar jointing meme/festival/whatever, I suppose I could throw a few photos out there…
Some of the oldest volcanics in the Vulsini volcanic district, Italy: a jointed trachyte from the Bolsena caldera complex. (The tree at the top of the cliff is about 3 m tall.) This is one of my favorite photos, because you can see multiple cooling sets divided by fractures – and it really emphasizes how columns form from inward-directed cooling.
Willow Mountain, Terlingua, Texas (near Big Bend). Beautiful columnar jointing throughout. (No scale on this one, but I’d say it’s about 200 meters from top to base.)
And, finally, an actual example of columnar jointing in basalt, which is probably much more common than jointing in an any of the other stuff I’ve mentioned: a lava flow near St. George, Utah. (Wish I could figure out where, but Google Earth isn’t helping today. Has anyone seen this abandoned water tank?)
Jessica Ball is a volcanologist at the U.S. Geological Survey, researching volcanic hydrothermal systems and stability, and doing science communication for the California Volcano Observatory. She previously worked at the Geological Society of America's Washington DC Policy Office, learning about the intersection of Earth science and legislative affairs. Her Mendenhall postdoc and PhD focused on how water affects the stability of volcanoes, and involved both field investigations and numerical modeling applications. Her blogging covers a range of topics, from her experiences in academic geosciences to science outreach and communication to her field and lab work in volcanology.
I really like the picture of the jointed trachyte. Is that the name for such a radial cooling pattern (if that makes sense)? There's an outcrop in the Columbia River Gorge that exhibits the same pattern. I never knew what it was called though.
(Wish I could figure out where, but Google Earth isn't helping today. Has anyone seen this abandoned water tank?)This picture is of a scene just north of St. George — people drive right by it on I-15 all the time (between exits 13 and 16 from I-15), but only we select few know how cool it really is….
From Dave Tucker at Northwest Geology Field Trips: Dear Tuff Cookie and friends of columnar jointing,I took Jessica’s comment about someone in Washington declaraing ‘Columnar Jointing Week’ literally and decided it would be quicker and easier to post pics of columns in Washington State rather than wait ‘for someone in Washington’ to declare National Columnar Jointing Week.The post and pictures can be found at http://nwgeology.wordpress.com/2010/09/29/columnar-jointing-in-washington/
Got you the coordinates of the St. George basalt on Google Earth: 37°09'29.64"N, 113°28'22.11"W.
Hi Jessica! My Volcanology Group runs a Volcano blog (deliberately in Hungarian language). Following your announcement to have a Columnar Jointing week I posted selected photos from the exceptional nice columnar jointed volcanic rocks of the Carpathian-Pannonian region, eastern-central Europe. Visit: http://tuzhanyo.blogspot.com/2010/10/oszlopos-lavakozetek-kiveteles.html
I’ve been looking all over the internet to try and find this and what it is called because I drive by it on my way from California to Colorado and it looks just like Devils Postpile, I can’t believe nobody really even knows what they have here especially for being so easily accessible. This website is the only thing I was able to pull up and that water tank thing is right there, I remember. Dinogami, those coordinates are exactly the spot. Now each time I drive by, I can know that it is what I thought, columnar basalt.