Friday, November 13, 2009

Friday Fault Photos: East Klamath Lake Fault Zone

I'm taking a bit of a backstep in our journeys to and from the Portland GSA meeting - back to the East Klamath Fault Zone because, after all, it's Friday. (Google Maps location of this fault exposure.)

These photos are my attempts at digitizing 35mm slides taken in 1998, by way of holding the slides up to the sky and shooting them with my 10MP digital Cannon. Results: contrasty, strange color balance, a little bit of bluriness, but better than nothing until I get a slide scanner (or take the slides out for a pro job). Ah, but the blues are great! Can't tell what the original film was, probably an Ektachrome of some kind.
Photo from the base of the fault looking northwest across Upper Klamath Lake. The rubbly material in the foreground is rock in the footwall of the fault, basalitic cinders and bombs, possibly brecciated.
The fault! The brownish rocks seemingly piled against the fault on the left side of the photo are what I interpreted to be older colluvium in the hangingwall of the fault.
The fault plane with a short-handled sledge for scale. Fault slickensides and striations are approximately parallel to the hammer handle. (It was very steep up there, and hard to get everything to align perfectly.) A bit of footwall breccia can be seen in the lower left. This photo will not enlarge.
Another photo of grooves on the fault plane, with the same hammer for scale. The hammer handle is roughly parallel to the fault grooves and slickenlines. This photo will also not enlarge.
Another view of the fault plane, this time looking toward the southeast. The fault plane is steeper than this photo suggests; I didn't try rotating it (the photo, not the fault). There were two ages (at least) of colluvium on the slope: the older, poorly sorted, crudely layered, bouldery debris appeared to be in the hangingwall of the fault; the finer-grained, layered material beneath a rabbit brush in the right part of the photo mimicked the current slope and appeared unaffected by the fault.
I encourage you to walk up and look at this for yourself - the views and the fault are both spectacular.


Sue said...

Great pictures. I especially loved the education on faults. Thanks. Geology Rocks... I know, old joke.

Gaelyn said...

Nice pictures and examples of the Klamath fault. That first image is rather strange.
Geology DOES Rock! Old joke or not.

Silver Fox said...

Thanks Sue, and Gaelyn! I don't usually say Geol Rx - but, hey, it does.

Maybe the strangeness of the picture is because I probably used a wide-angle lens, and maybe because of the deep blue color permeating everything. You can see my footprints, though! :)