Friday, April 2, 2010

Baked... Lake Sediments?

Just a quick preview of a roadcut on Highway 36 near Susanville, CA, showing a basalt flow over some white [probably tuffaceous] lake sediments. The reddish baked zone may might include subaerial deposits.

And a closer view:
This roadcut was heavily modified in 2009; the exposure now totally sucks.

More on this later...

UPDATE (3Apr10): This post was inspired by Callan Bentley's post on Baked fanglomerate at his (relatively) new blog Mountain Beltway. I thought, perhaps, that posting another baked zone would result in a meme that would propogate through the Geoblogosphere, but so far it's a mini-meme of two. :)

Andrew Alden, About.com:Geology, has a great geological wallpaper of a similar baked zone near Alturas, CA - check it out! I wonder if the two roadcuts are expose the same basalt flow.

UPDATE (4Arp10): More geobloggers have joined in this geomeme, Ron Schott has a baked contact (?) on a green sand beach on Hawaii, and Kyle House has a photo of a baked carbonate soil in colluvium on the Owyhee River.

11 comments:

Coconino said...

Aww. I hate it when departments of transportation mess up perfectly good road cuts!

mountainbeltway said...

Nice coincidence of timing: I posted today about contact metamorphism of sediments, too!

Dr. Jerque said...

I see that cut on my way to Bend all the time. Probably a great story...have you any age information about it?

hypocentre said...

In the UK we would have designated this a regionally important geological site (or RIGS). It would have been harder to mess with.

Suvrat Kher said...

great looking red layer. in the Deccan Traps you get similar looking layers..they are red tuffaceous material between two lava flows.

Silver Fox said...

@Coconino: I have pics of their nasty work in progress, which I will get around to posting, maybe I can work on it tomorrow (a day off).

@Callan: I'll update here with a link - it wasn't coincidence, I saw your post and put this up right before work.

@Dr. Jerque: I really don't have any ages on this, haven't tried searching for geological info online. Maybe in the Roadside Geol of northern CA?

@hypocentre: I think that this roadcut was modified in response to an accident between it and at least one vehicle. If so, I understand their action, though was appalled to watch it happening. Widening the shoulder without affecting the roadcut would have been impossible. It's really too bad it's gone.

@Survrat: the white layers are probably tuffaceous, maybe or maybe not deposited in a lake - I wish I knew more detail about the geology. If I have my roadside guide handy, I'll see if they have anything to say about it!

Dr. Jerque said...

I thought this may be the one near Alturas...if not, then it is also very nice and likely remains intact.

Silver Fox said...

This former roadcut (there still is a roadcut, but it just doesn't show anything) is practically in downtown Susanville barely west of town, on Highway 36, the highway to Lassen and Red Bluff. Sorry I didn't have time for a location link, will try to remedy that in the next post, whenever I get the time.

Silver Fox said...

Dr. Jerque, on the way to Bend from Reno, one would not ordinarily pass by this roadcut. From Reno to Bend, I go through S-ville then turn north to go by Eagle Lake, which misses this roadcut by half of S-ville town.

Dan McShane said...

I saw that road cut four years ago. I was a bit nervous at the time as it was snowing hard and I was without chains.
I'll did around and find some minor baked photos, but nothing as good as that.

Silver Fox said...

Dan, let me know if you post something. I'll try to update here about your post. :)