Sunday, April 16, 2017

Blue-Gray Limestone, Crinoids, and Large Quartz Crystals in Western Arkansas

     Yes, this is Maizie and me licking our lips (or nose, in her case) at the striking roadcuts of the Ozark Mountains (actually plateaus) of northern Arkansas and the Ouachita Mountains of west-central Arkansas.

       The western part of Arkansas includes, from north to south: the Ozark Plateaus or Mountains, the Arkansas River Valley, the Ouachita Mountains, and the West Gulf Coastal Plain. The Ouachita Mountains are one of the few east-west-trending ranges in the U.S. (The Uinta Mountains in Utah and Mt. Tom/Mt. Holyoke Range in Massachusetts are two of the other east-west-trending features.)

      The geologic units are outlined below, including shades of blue for blue-gray Mississippian rocks. (NB: unless one is a geomorphologist, most geologists just gloss over anything coloured yellow for the Tertiary and Quaternary.)

       The Mississippian Pitkin Limestone is 360 to 320 years old and is chucky-jam full of fossils, including crinoids and bryozoans. The crinoid stems (which resemble rolls of Smarties candies) are parts of animals called sea-lilies that attached to the seafloor. In this rock sample, which may or may not have travelled from northern Arkansas to Colorado, shows the unweathered fossils.

        Here are some weathered out crinoid stems.

        And here is the stem and the less-often preserved top of a crinoid animal.

       The photo below shows weathered-out screw-shaped bryzoans, commonly referred to as Archimedes screws (in the right bottom part of the photo.) The upper left part of the photo shows the crinoid stem pieces. The crinoids are so plentiful in the Pitkin Limestone that some people apparently fling them on the ground like pop-rocks. We did not partake of that practice.

      The Pitkin Limestone overlies the Fayetteville Shale as seen in this roadcut. The "tight" shale is the source of much gas development in Arkansas via hydraulic fracking.

      One of the most spectacular parts of our Natural State of Arkansas journey was traveling south along state route 7 from Russellville to Ouachita Hot Springs National Park, right through the heart of the Ouachitas.

         Here's the view (with Maizie) toward the Arkansas Valley:

        Ouachita Hot Springs National Park:

       Pictured below are some large quartz crystals from Blue Springs, Arkansas, which are now at the Crystal Bridges American Art Museum grounds in Bentonville.

       . . .And a few images incorporating geology and art from Crystal Bridges:

      And lastly, a beautiful morning with cool mist in the Ozarks somewhere between Mountain Home and Eureka Springs:

Have you explored Arkansas? Hoping you had/have a traveling companion and navigator as amazing as Maizie. . .



  1. During the Civil War, men from Arkansas fought for both the Blue and the Gray. Perhaps matching the blue-gray color of the Pitkin Limestone? ;-)

  2. Steph,
    It's a very "Civil" blue-gray blog subject!
    Love "chucky-jam."
    Great "Maizie-Licking-nose" photo. My kitten Smitten cannot do that. I recall, however, that my mom's adoptive mom (who taught me how to play solitaire as a young lad) could.


    1. Thanks, Lego. Maizie and I share the ability. Smitten may get there. ;-)

      We went to both Arkansas State and U of Arkansas. Both are great towns. The ASU Museum is great, too. Have you been to the South Wind State?

  3. I've never been to Arkansas, nor any of the adjacent states, nor have I ever understood why it's pronounced that way and not like "Kansas" with an extra syllable. Didn't Crystal Bridges sing "Don't It Make My Brown Eyes Blue-Gray"?

    1. Yeah, the Crystal Bridges jokes are plentiful. Terrible name for a beautiful place.

      And, while we're at it, why is it usually blue-gray not gray-blue?

      Here's some insight into the Arkansas vs. Kansas pronunciation.

    2. Maybe there's an implicit color order in English, like the adjective order I could swear we've discussed before, but which doesn't appear in search results.

    3. I remember that discussion, jan.

      I cannot see a overriding order to colors other than blue tends to go first as in blue-gray or blue-green. But, wait, then there's black and blue. . .

    4. According to Crayola, twice as many people favorited (?!) yellow orange as orange yellow.

    5. I can see why. That orange yellow is blah.

      "an overriding" above, btw.

    6. Another name for blue-gray is livid. Livid comes from the Latin color term lividus meaning a dull leaden-blue color.

      Huh. Different for me than feeling livid (a hot, red, burning color).

      Rats, I can't remember what 51, 6, and 500 are using Roman Numerals. I am LIVID!

    7. When a person dies, the blood, no longer circulating, pools in whatever areas of the body are lowest, resulting in a dependent line of lividity. EMTs are taught this, since it's a sign that CPR would be futile.

    8. Interesting. So, not to be too macabre, but a person hung on a cross would then have a line of lividity near their feet then. I think that is portrayed in some paintings of Jesus Christ on Good Friday.

    9. A person, yes. What happens with divine beings is above my pay grade.

  4. Since we often discuss recent scientific papers on this, blog, I thought I'd share this announcement of a new browser extension called Unpaywall, which provides access to publically-available versions of academic papers previously locked behind publishers' paywalls.

  5. Science in America: Neil deGrasse Tyson (4 minutes). Preaching to the choir here, I know. . .

  6. Happy Earth Day!

    We are getting signs ready for Denver's March for Science today. Got any good sign ideas?

    1. How about Piper Chapman's credo from Season 1 of Orange is the New Black? You may need a few friends to help you carry it...

      I believe in science. I believe in evolution. I believe in Nate Silver and Neil deGrasse Tyson, and Christopher Hitchens. Although I do admit he could be a kind of an asshole. I cannot get behind some supreme being who weighs in on the Tony Awards while a million people get whacked with machetes. I don't believe a billion Indians are going to hell. I don't think we get cancer to learn life lessons, and I don't believe that people die young because God needs another angel. I think it's just bullshit, and on some level, I think we all know that, I mean, don't you?... Look I understand that religion makes it easier to deal with all of the random shitty things that happen to us. And I wish I could get on that ride, I'm sure I would be happier. But I can't . Feeling aren't enough. I need it to be real.

    2. jan, I like it. Not sure I have enough ink for all of it, though.

      Maybe a condensed version will work.

      Now, we just need the steady rain to abate. Things don't start until 10 a.m. here so the weather might cooperate . .

    3. A little late, I realize, but my brother-in-law sent pix from the march in NYC. His favorite signs were carried by a couple. They showed the appropriate mathematical function curves; one read "PROTEST SINE", the other, of course, "PROTEST CO-SINE". His runner up said, "NOT PROTEST SIGN. PRO-TEST SIGN. SHOW ME THE DATA."

    4. Those are great. My favorites from Denver:

      If you're not part of the solution, you're part of the precipitate (alternative facts).

      There is no planet B.

      A polar bear on a tiny iceberg saying simply and quietly "f**k."

  7. New post on "Arkansas Novaculite: 99 Percent Pure Microcrystalline Quartz or 'Arkansas Stone'" is now up, including photos from today's March for Science in Denver.