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You are browsing the archive for analogies Archives - Mountain Beltway.

8 May 2014

Honey crystallization as an analogue for magma segregation and cumulate textures

Check this out: Maybe I’ve got low blood sugar, but I think I see a magma chamber in that jar of honey. There is clearly some crystal settling going on there, and it appears that the more crystals there are, the easier it is to trap bubbles. When the clots of crystals get too dense, they peel off (stope) and drop down to the floor of the jar. Similar sorting …

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7 March 2013

Snow day aftermath

So we ended up getting 13 or 14 inches of snow yesterday. It was wet, and the temperature was right around freezing. As soon as it stopped falling, it started melting. One interesting aspect of this is that big wads of slushy snow were plopping off the trees every time a gust of wind came through. The structures these “plops” formed exhibit much of the same morphology of meteorite impact …

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18 December 2012

Diaper diapir

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17 October 2012

Convection in a dirty dish

Saw this in a greasy / soapy baking pan in my kitchen sink the other day: Do you see those lobe-shaped light areas, separated by dark septae? I think that’s the semi-gelled signature of gravitational instability, perhaps thermally driven. I’m speaking of convection: upwelling in the round light areas, and sinking of denser material in the dark seams in between. A closer look at the structure of the suspension, and …

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18 August 2012

Migmacatization

Evelyn put up a cat photo on Geokittehs earlier today, and it reminded me of anatexis, the process of partial melting. Anatexis is my favorite way to produce a migmatite. In this model, the light-colored (felsic) ginger cat is derived from the partial melting of another cat, partly dark (mafic) and partly felsic (ginger). Where the low-melting-temperature minerals have been extracted, the source cat is much darker. Fresh injections of …

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23 May 2012

Fossil Falls fun

A few shots from Fossil Falls, in the southern Owens Valley, California… This is the now-dry river bed of the Owens River. There’s abundant evidence of water-induced erosion (potholes, polishing, etc.), but nary a drop of water to be seen – Though this particular portion of the Owens River drainage dried up in the Pleistocene, it parallels the more recent history of the valley’s water resources, which are now being …

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12 February 2012

Fractures on a seismic sign

On the campus of the University of Texas at El Paso, there is a sign for the Kidd Seismic Observatory. The sign has seen some brittle deformation of its reflective letters. I infer this due be due to differential shrinkage of the letters (relative to the sign they are attached to) in the intense Texas heat. I like seeing deformation in materials other than rocks. This is a neat example …

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29 January 2012

Tofu with hackle fringe

We were making dinner last week and took out a block of “silken” tofu* with less care than we should have, and it broke. But what a break! The fracture showed a gorgeous elliptical joint face that broken up into a twisted series of hackles along its fringe: That’s something nice homogeneous fine-grained rocks do, too! I hereby challenge all my tofu-eating readership to attempt similar tofu-fracturing experiments, and to …

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22 January 2012

Rheology of an overheated waterbottle (with stickers)

Last fall, when I was out backpacking in Dolly Sods, we left one of Lily’s water bottles on the dashboard of the locked (and windows-rolled-up) Subaru. When we got back to the car, we found it had experienced heterogeneous solid-state deformation. I took a few photos, so that those of you who are interested in rock deformation could ponder them as analogues for the contrasting styles of deformation we see …

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30 September 2011

Friday fol(r)d

Straight-limbed open synform in an organic-rich formation of limited areal extent, featuring some brittle extensional features at the hinge. Kootenay National Park, British Columbia, summer 2011. (The bridge was broken before we got there.)

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