“Boudinage” and “transtensional” are #1 in my geo-lexicon, but Callan Bentley took boudinage and I’ll leave “transtensional” for another day as it was the topic of my first graduate thesis. “Crenulation” it is for Accretionary Wedge Episode 35: What’s Your Favorite Geology Word? This comes from my fascination with polyphase deformation, or multiple episodes of deformation, leaving their imprints on rocks in the form of cross-cutting fabric.

I used to explain crenulation to my students with their own palms, as shown in the image below. Start out with your palm facing up. Then, cup your palm until you see creases (folds) in it. Following that, take your other palm and push your folded palm in a direction roughly perpendicular to the folded palm’s fingers. See the interference pattern as new folds (D2) overprint the old ones (D1).

1. Flat open palm 2. Folds (indicated by blue lines) form perpendicular to fingers when hand is curled 3. Palm is folded again in direction perpendicular to previous curling. New folds (red lines) form; note deformation of previous folds.

No demonstration of deformation is complete without Play-Doh, which is luckily available from VatulBlog HQ’s always freshly-stocked shelves. (Gotta love the warning: Fun to play with, but not to eat. NOTICE TO PARENTS: CONTAINS WHEAT.)

Left: Folds form in Play-Doh roughly perpendicular to direction of squishing (yes, that's a technical term, and indicated by the black arrow; black lines are fold axes). Right: Second episode of deformation (indicated by red arrows and red fold axes) overprint previous folds (note that black fold axes are now folded themselves).

Now, my hands smell like Mmmm Play-Doh. Is there anything it cannot do?

Earlier, I mentioned the term “fabric.” Rock is not a homogeneous, isotropic substance like Play-Doh, but instead a collection of minerals that have different physical and chemical characteristics and geometrically rearrange themselves differently under varying stress-time/pressure-temperature conditions. Therefore, crenulation is best viewed at the microscopic level. At this scale, we can see what really happens to the rock’s constituent minerals when they undergo successive episodes of deformation.

Metamorphic thin sections in the next exciting installment of CRENULATION!

Katrina’s Secrets. It’s a new book by Ray Nagin, the ex-former-gone-but-comes-back-like-exzcema mayor of New Orleans. Self-published. Mmmm hmmm. Barely ridiculed on The Daily Show. The title reminiscent of a discount lingerie store where, as I said on the twubes, there is always a “50% off sale on purple-green-gold thongs, misspelled tourist tees & adult diapers embroidered with family values and laced with eau d’oil spill.”

This is my favorite Nagin line from a presser that The Gambit attended: “There were recovery strategies put in place early that are now paying dividends” By the way, El Gambito reads the book so we don’t have to … just yet.

Politicians have gone beyond lying. They are now shamelessly turning lies into the truth. Right is wrong, who controls the present controls the past, ignorance is fraking strength. What you see is not what you see.

bry4n sent me a video on “diminished reality.” Amazing how you can alter reality with a bit of upscaling. Just because you’re looking at something doesn’t mean you see things as they are.

Through, from the Once Upon A Wall series by artist Aakash Nihalani. (more at Sepia Mutiny)

On the road this week. I leave you with the latest from a geo-blog which must go in my feedreader once I get back. It seems that Hollywood is putting out another sciencepocalypse (or is that scienceageddon?) film, this one entitled 2012: Ice Age.

There’s a volcano. It unleashes a glacier. Don’t ask me how. But it’s a fast glacier. A really, really, really, really fast glacier [that’s] like a brazillion thousand miles across and can get from the Arctic to the US in a day or two, because it is seriously pissed off and has installed a turbo. And then it destroys New York City, because that’s what you do when you’re the world’s fastest glacier that’s been set free by a volcano.

… One of my guildies suggested that this movie should actually be Speed 3, with Keanu driving the glacier. I am not ashamed to admit that I would pay perfectly good money to see that.

Oh, and one more thing. I’ve completely lost my mind seeing as how I just signed up for the 2011 Susan Komen Houston Race for the Cure. For the next fifteen weeks, I am back on the Couch Spinning To 5K wagon. If I’m not blinded by all the pink around me on race day, I may just make it to the end. (But first, once I hit “Update,” I am going to find a corner and cry like a little girl.)