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Posts Tagged ‘baking’

(this submission to the Accretionary Wedge #30 Bake Sale is late due to a missing camera.   Luckily, someone found my camera and now I can show off my baking “mistake”)

My original goal was to bake a metamorphic rock cake that had a bimodal distribution of porphyroblasts.   I was going to use green & blue sprinkles to defining the schistose layering (micas) and two different sizes of chocolate chips (the normal & minis) to represent a bimodal garnet distribution.   Instead of going the “easy” route, I decided to crack open my copy of Fannie Farmer and make the cake from scratch.   This is what came out of the oven:

my non-metamorphic cake

Well, that’s not a schist.   So what happened?

I had assumed that the viscosity of the cake batter would prevent the chocolate chips & sprinkles from moving very far within their original location in the pan.   However, as the cake went into the oven, the viscosity of the batter went down and the “garnets” started to settle at the bottom of the pan.   Which, had I had a way to capture the movement, would have been a great example of crystal settling within a magma chamber:

The blue & green sprinkles were not as heavy as the chocolate chips, so they simply homogenized within the “magma chamber” and gave the cake its green look.   My oven also has issues, so even though the middle of the cake had originally swelled and was a good bit higher than the edges, during cooling the center “caldera” of the cake subsided.   A similar process occurs with volcanoes when you remove the magma from the chamber either quickly (a massive eruption like Pinatubo in 1991) or slowly draining it (Mauna Loa from 1983-2001):

So, ironically enough, I didn’t produce a schist, but I managed to accidentally make a fairly decent mafic volcano similar to what might be found in Iceland 🙂   I’ll have to try again for the schist sometime this spring.

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I’m beginning to wonder if I’m even supposed to post something from Callan’s bake sale.   The signs are not promising at the moment…

  1. my nicely thought out bimodal garnet distribution mica-schist cake used up all of the eggs, cornstarch, and butter in my house; this would have been fine except for…
  2. the batter wasn’t thick enough and instead of getting a random distribution of “garnets” I managed to produce a cake that looked more like a volcano with a cumulate layer on the floor of its magma chamber
  3. the center of the cake refused to actually finish baking
  4. it tasted good (how could anything with a chocolate cumulate layer not taste good?) and I took pictures
  5. I though that I would try again last night with a different batter, but I’m out of critical baking components
  6. my camera has magically disappeared since yesterday

I’m really hoping the camera appears by the end of the weekend.   But at the moment, I’m submission-less.   Sigh.

I need to go back to grading field guides, so I’ll look once again once this next round is done.

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I attended a bridal shower Saturday afternoon that was held for a geology friend.   Everyone at the shower was either a geologist or worked with geologists.   The hostess wanted to create something that reminded the bride-to-be of her home and went with a stromatolite cake!   Now, the geologists in the room don’t blog, so I’ve taken it upon myself to post pictures of her cake as a tease for the Accretionary Wedge #30.   I’ll post my own creation later in the week.

The cake:

the inside:

ok, so what is a stromatolite and why on earth is this cake a weird blue-green color?

Stromatolites are some of the earliest forms of life that have been found on Earth.  They are comprised on microbial mats within water that trap sediments into layers.   The microbes are made up of cyanobacteria, which are also known as blue-green algae (hence the food coloring choice!).   There may also be non-bacterial stromatolites, but we’ll avoid that topic for the moment.

The oldest preserved stromatolites at the current moment are somewhere between 2.7 and 3.5 billions of years old (I’m not getting into that uncertainty right now), which considering we don’t get hard parts until the Cambrian explosion ~580 million years ago is quite amazing.

Australian stromatolite (note the layering):

Some of widest arrays of types of stromatolites can be seen at Glacier National Park (~800 million years old):

Cambrian stomatolites in Sarasota Springs, NY:

The great thing is that unlike many organisms that have come & gone on the planet, we can still go and see live versions (they dominated in the Proterozoic, but are relatively rare now).   Here are some modern examples in Shark Bay off of Australia:

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