Friday, January 18, 2013

Geo 365: Jan. 18, Day 18: Basin and Range on the Roadside

A very, very nice horst, and a sweet little graben to its upper right, a bit up the road from the exposure I've been going on about since Monday. What with the Jersey  barrier, the groin behind that, and busy traffic, we chose not to even try crossing here, but just took photos and enjoyed the fantastic faulting from across the road. I had been a little confused about what exactly was going on here, because I'd been under the impression the road was running north-south. Elsewhere, it mostly is. But along this stretch, where we're climbing up out of the Klamath Basin, to what I refer to as the "east side apron-" the flat apron of pumice and ash from explosive High Cascade volcanism- the road is actually running about NE-SW, so the angle to Basin and Range structure makes better sense. Still, I'm suspicious that this is not quite as simple and straight-forward as it looks... I'd *really* like to get up close and personal with this outcrop.

I had never stopped here before, and I don't think I'd even noticed how great this road cut was, despite having passed somewhere around 15-20 times over the years. It actually was a very fortuitous stop, because Dana had never seen Basin and Range consciously, so I was able to use the structures exposed here to introduce her to the structures we'd be seeing on a much grander scale over the following couple days. 

The rock here also appears dominantly tuffaceous, with beds of gleaming white diatomite and black lignite.

Photo unprocessed. August 18, 2011. FlashEarth location (Cross-hairs on pull-out. The high tension power lines are the landmark to look for, here- this is the main conduit for taking Columbia River hydropower to California.). If you choose to visit this spot, please see Monday's safety comments; as I commented above, we chose not to cross here.


Hollis said...

Neat shot. Is that ponderosa pine?

Lockwood said...

Almost positive it is. If you right click the photo, open in new tab, then enlarge to full size, you can see the bark more clearly- and it has that typical ponderosa "crackle-look" to it. Tomorrow's photo will be of same features, zoomed closer in, and more sqarely-on. This one mostly to provide sense of scale for that one.