Thursday, November 18, 2010

Of Coffee, Trees and Rocks

I don't think it's quite yet a geo-meme, but in the past day both Garry Hayes and Callan Bently have posted lovely photos of fall foliage around their stomping grounds. Which reminded me there have been a couple of tree-and-rock related things I've been admiring outside the Interzone. The two commercial rentals next door are being remodeled for something, and that includes replacing the windows, apparently. So here are a couple of pictures of place-holders for the window panes:"What does this have to do with geology," I hear you cry.
Well, take a look at this:From Oxford's "Rocks under the Microscope" page, muscovite-biotite schist thin section in plane polarized light. I think it indicates a certain degree of obsessive nerdliness to look at this:
...and be mesmerized by its resemblance to a medium-high grade foliated metamorphic rock.
This magnificent ginkgo is more in line with the fall foliage theme. Every year, this tree seems to hold on to its summer greenery a few weeks longer than most of the other trees, then almost overnight, transform itself into a billow of golden fire.
But once again, what does this have to do with rocks? You didn't click the "ginkgo" link above, did you? Ginkgo is most famous for being a "living fossil," that is, an organism that has survived for many millions of years with very little change. Fossils of Jurassic and later ginkgoes are essentially indistinguishable from the modern species, and very similar species are found as far back as the Permian. Wikipedia has some interesting information on their history and ecological habits.
Part of my fascination with this tree is the stark contrast between it and its neighboring fir.
In a quick walk around the block, above is a gum tree- they've been quite vibrant this year, but the leaves are quickly falling off now.
And this is a little ornamental maple partway down the block from Interzone.
This is a cross section, or transverse section, through a sample of permineralized wood that normally sits on the table next to my traditional station at the Interzone. I think this may have been a gift from my friend and colleague Larry Enochs. If so, it came from the Holley, OR area, where a remarkably diverse Oligocene to early Miocene flora has been preserved in astonishing detail. Irene Gregory's 1968 paper in The Ore Bin makes for a good read (1.85 Mb PDF). However, I'm not absolutely positive that this piece is from that area. Below is a radial section- 16 oz. coffee glass for scale.
Next is an approximately tangential section...
...and an oblique shot- I have labeled the surfaces on this, X, R, and ~T, for cross (transverse), radial, and tangential, respectively.
Followup: I love synchronicity... the very first thing I looked at after finishing this post was the cover of this month's GSA Geology Journal.


mountainbeltway said...

I have had this same thought when it comes to particle board. Glad you committed the analogy to the blog -- it was one of the many ideas I've had that have slipped away over time.

Silver Fox said...

It looks a little like "diabasic" texture - but not quite. I think you really nailed it. I look at linoleum and see rock textures, also.