Accretionary Wedge #5: Geological Misconceptions and Pie

Happy National Pie Day, and welcome to the fifth edition of the Accretionary Wedge, the Internet’s premier blog carnival for the earth sciences! First, I have some news for you. Make sure you’re sitting down before you read this:

In other news, Mel discusses a test designed to expose students’ geological misconceptions – and why it might not always work. Saxifraga talks about what glaciers actually do – “The moraine five kilometers in front of the modern glacier margin is not a sad sign of the ice retreat, but a sign of a not climate related natural phenomenon called glacier surge and the retreat from the Little Ice Age moraine is partly an adaptation to warming over the past 100 years.”

In honor of National Pie Day, Callan Bentley shares his favorite baked-goods teaching analogies – but he hasn’t thought of any pielike concepts in geology, maybe you can help? Brian objects to the “layer cake” analogy, suggesting that perhaps we should use lentils instead. Lentils? I guess I’ve seen recipes for lentil shepherd’s pie…

Finally, Lab Lemming has a delicious rocky planet pie chart, and by “delicious” I mean “my dentist told me only to eat gas giant pie charts”.

Trackbacks & Pings

  1. goodSchist » Blog Archive » The GeoBlogosphere Review #1 on 23 Mar 2009 at 7:47 am

    […] at Highly Allochthonous states the obvious, referring to Brian’s post in the Accretionary Wedge #5; Brian might not like it, but I think this t-shirt is pretty […]


  1. Yorrike (Chris) wrote:

    Wow that’s a lot of posts. Looks like this little carnival is going from strength to strength!

  2. Yorrike (Chris) wrote:

    Oh, and thanks for hosting, Yami.

  3. Lab Lemming wrote:

    Looks great. A couple of questions, though.

    When you say the above crust is “thickening”, are you inferring that from mass balance and the shortening component?

    And isn’t the core more annoyingly underconstrained than the mantle?

  4. yami wrote:

    Yes, most of the thickening is caused by the shortening. But these things are conventionally done by energy balance calculations.

    The core is usually easier to ignore than the mantle.

  5. Andrew Alden wrote:

    Well, it isn’t pie, but I have this page about geologic recipes and another about volcano recipes that mentions soufflé.

  6. ChrisR wrote:

    Brian at Laelaps has also weighed in:

  7. Kerr wrote:

    Point: It wasn’t actually the joke, which was trite, but the art, and others are better:

  8. Aquinas Dad wrote:

    Not to be *too* annoying, but ‘Santa Claus’ is usually a reference to St. Nicholas of Myra, an historical figure. While much legend has grown up around him (oddly more amongst non-Catholics than within the Church) was was a real guy.

  9. yami wrote:

    Aquinas Dad, I think you’re overestimating the role of history in the modern Santa myth. Santa isn’t a fourth-century bishop any more than legends must be read rather than listened to.

    Besides which, St. Nicholas of Myra fills your shoes with candy on December 6, and Santa Claus puts presents in your stocking on December 25. Totally different guys (and one of them is a plagiarist).

  10. Kim wrote:

    LL: I guess the question is whether the crust involves shortening or butter.

    Also, the core(s) are generally left out, at least in apple pies.

    (Thank you for organizing this, and I apologize for my entry. I couldn’t even find a pie photo that wasn’t copyrighted, let alone come up with the puns necessary for the occasion…)

  11. Aquinas Dad wrote:

    Maybe my view is more skewed because I am a pretty traditional Catholic, but ‘St. Nicholas’ brings candy on Dec. 6th and then we get each other stuff on the 12 days of Christmas. Don’t confuse American/Canadian marketing with what the majority of Catholics/Orthodox world-wide practice! I had to step in when my (very puzzled) children began to explain to a neighborhood kid that of *course* St. Nick is real – he’s just been DEAD for a long time!

  12. JohnnieCanuck wrote:

    Something tells me that without the intercession of the children’s parents, the ‘Saint’ would be powerless to miraculously put candy in shoes.

  13. Aquinas Dad wrote:

    Well of course not – and the kids know it. Its about those who have giving to those without and the joy of giving surprises, especially to kids.

  14. Andrew Alden wrote: is doing away with my blog, so I’ll post the text of my entry here:

    I get the Geological Society of America’s monthly GSA Connection newsletter, and it’s almost always good. But I have to bust them for promoting a good site’s poor page. The site, named as a resource in this month’s newsletter, is the University of California Museum of Paleontology site, an excellent source for anything connected with fossils and evolution. But its page on plate tectonics is old and not fully correct. It repeats a couple of long outmoded ideas. One is that the plates of the lithosphere are moved about by convection currents in the underlying mantle, like porridge on a stove. Not so: it is the plates, cooling and sinking at subduction zones, that stir the mantle instead. (This is one of the most common myths of plate tectonics.) The other is that lava comes from the asthenosphere, the soft layer of rock beneath the plates, because of its heat. Not so: it is water injected into the mantle by subducting plates that causes the overlying rock to melt, not extra heat. Both of these mistaken notions have lived on in textbooks because they seem to be common sense. But plate tectonics is a living field, and the version it started out with 40 years ago has been superseded by surprising science.

    This page is a contribution to Accretionary Wedge #5

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