02 July, 2011

Garnet Mica Schist, People!

Some photos of that glorious piece of garnet mica schist I found on the hill behind my house:


There she is!  Kitteh for scale.


So sparkly!


And a shot through ye olde hand lens.  Look!  Garnets!

I have no idea where this thing actually came from.  The hill behind my house seems predominately outwash, and there isn't bedrock around so far as I know.  Certainly not bits of the metamorphic core.  I'm wondering if someone just abandoned it, like people do puppies.  No matter, it's got a happy home now.

Elli Goeke wrote the definitive series of posts on garnet schist.  If you want to know more about this beauty (and you do, you know you do!), see:

Metamorphic reactions — the basics

Mud to cordierite – sillimanite hornfels — contact metamorphism at work

Mud to garnet schist — regional metamorphism at work

I will be eternally grateful to her for writing these.  A round of applause, please, my darlings, and if you're ever lucky enough to meet her IRL, be sure to buy her a drink.  I owe her a few gallons, so I hope she's thirsty when we finally meet.

Don't be surprised if I post more photos of this find.  These were shot in haste on my lunch break, and it deserves better.  But several people have wanted to see it, and I just couldn't wait anymore.

7 comments:

Felis Catus said...

Is this mica schist too? Without the garnets of course!

http://dl.dropbox.com/u/3205168/2003-09-15_123752.jpg

Dana Hunter said...

It's hard to tell from photos, but it surely looks like it. Where's it from?

Felis Catus said...

Egean coast of Turkey.

Where I found looked like this:
http://dl.dropbox.com/u/3205168/2003-09-15_123718.jpg

Also found this in the same region, though much father away:
http://dl.dropbox.com/u/3205168/P6130007.JPG

Silver Fox said...

Oooh, Dana! Maybe it came all the way from Idaho in a Scablands flood! Not that I recognize it in particular.

Felis, the first two look like schist, or phyllite its lower grade cousin.

lyle said...

Since you think it lies in an outwash area, think where the glacier came from. In fact it sounds like rocks described here in North Cascades National park: http://geomaps.wr.usgs.gov/parks/noca/nocageol2c.html and possibly further south from the park. It makes sense since the glaciers flowed downstream. There are some posts pointing out such a rock in the Wenatchee block which is in the Stevens Pass area (US 2). This makes a lot of sense, given that the glaciers were likley flowing southwest from this area to reach the sea.

Here is a nice post from the University of Alabama on the Wenatchee area: http://www2.geo.ua.edu/fieldtrip_2010/Templates/NC.html

lyle said...

Further here is a nice trip report/road log on the Alabama trip from Hells Canyon east: http://www2.geo.ua.edu/fieldtrip_2010/Templates/main.html

Markita Lynda: Healthcare is a damn right said...

Fabulous. Ièm going to take a picture of the rock I found near Huntsville, Ontario and send you a link. It looks like white granite with red spots.