Lapidaryforum.net
Let's Rock => Rockhounding Tips, Maps, Trips Etc. => Topic started by: Kaljaia on May 06, 2016, 11:16:38 PM
-
There's a place up the valley across the creek from my house, where some very interesting geology is exposed. On top is a massive single sheet of basalt, broken along a fault line. Under it is evidence of prior flows, layers of fine sedimentary rock with leaf fossils, a two-foot-thick crust of white volcanic ash, bentonite patches full of rounded river rock, pillow basalt over shale beds, and welded tuff. I want to photograph the whole set sometime, but for now here's what a cell phone cam on an overcast evening could get.
The top cap rock. The line of cliff continues across several hills.
(https://65.media.tumblr.com/97ede3337bc7b89ad29c08087b0e703b/tumblr_o6sjfk8nvh1spns93o6_1280.jpg)
The ash layer
(https://65.media.tumblr.com/d34848e3defd76a91e51d0ddd26f8d46/tumblr_o6sjfk8nvh1spns93o10_1280.jpg)
River rock exposed in a draw. A layer of welded conglomerate above it is like aggregate cement.
(https://66.media.tumblr.com/ed5e04f239fa30094c472eaf7e7145f4/tumblr_o6skczxZEw1spns93o1_1280.jpg)
River rock that I want more of but could only find one piece.
(https://66.media.tumblr.com/f348fe22c56d6c0d1be4df851ac45e6c/tumblr_o6sjfk8nvh1spns93o8_1280.jpg)
Leaf fossil from the sediment layer below the river rock.
(https://67.media.tumblr.com/ba7229c831411ec311a04a1b92e3c875/tumblr_o6sjfk8nvh1spns93o9_1280.jpg)
Agate from the basalt layer.
(https://67.media.tumblr.com/cd1a55208e15283f2b9129c0c3a593e4/tumblr_o6sjfk8nvh1spns93o3_1280.jpg)
(https://66.media.tumblr.com/95a260f2863ae332be804c2c8f361725/tumblr_o6sjfk8nvh1spns93o4_1280.jpg)
Breccated, quartz-filled metamorphic was-shale from where the shale and basalt meet.
(https://66.media.tumblr.com/c8e2d9af17712df7d310d5d458e9e229/tumblr_o6smc674Na1spns93o1_1280.jpg)
Will be going back to inspect the river rock and metamorphic shale more closely...
-
fantastic place to hound, lucky dog.
look at that material you get there, beautiful stuff.
-
Now THAT looks like FUN!!!! :thumbsup: :icon_sunny:
I could definitely go with more of that Green rock you found too, that's pretty. There probably is more around there hiding very well.
I'd clean up the leaf fossil and set it on a nice display easel.
-
I could see me setting up camp at the fossil layer & staying a few days. :drool: :drool: :drool:
-
I will agree it's a nice spot :)
Some wonderfully accommodating person built a wide, well-groomed bike trail to within ten feet of the fossil layer, which I am shamelessly pulling apart in a way that would scandalize any true paleontologist, but you could pave a road with leaf fossils here so I don't think I'm in danger of mucking up anything rare. I might have bribed a professor with something from here once...
The other odd thing to come out of there was a small obsidian stone, water-rounded but fractured, which we thought was anthropogenic when we found it a few years ago but I am now wondering if it was also washed down whatever river or shoreline this used to be.
In a Fossils of Oregon book I've got, it mentions a part of this area as being an example of an exposed marine sediment layer, but I don't know which basalt layers that would have been between, and this also might have been one of the big interior lakes. The orange sediment with rounded river rock pops all over within a ten mile radius.
This will be a field trip spot if I get landed with the 4-H geology segment next year. Metamorphic, sedimentary and igneous rock all within inches of each other.
Anyone want to test that breccated material for me??
-
What do you want done to the breccia? You would have made one hell of a rockhound back in the day but with the modern twist of great information.
-
That area looks a lot like the Mitchell Oregon country, am I right ? :icon_scratch:
-
The brecca is interesting and those small pieces appear solid and fully healed, but I don't know if it'll take a polish because I'm not sure it's a consistent hardness.
That area looks a lot like the Mitchell Oregon country, am I right ? :icon_scratch:
Close, between Antelope, Ashwood and the John Day.
-
That looks like i neat place to go hounding.
Thanks for the photos.
-
Oh my gosh, what a gorgeous area, and such amazing specimens! I can't even imagine having an opportunity like that, living here in Minn! If I got out there I would never want to leave!
-
Oh my gosh, what a gorgeous area, and such amazing specimens! I can't even imagine having an opportunity like that, living here in Minn! If I got out there I would never want to leave!
It definitely had an impact on why I have the job I have now. I wouldn't do the work I'm doing if it didn't involve access to these places.
Everywhere has beautiful places. I have seen photos of scenery and agate from Minn.; It's a place I'd love to visit someday too.
-
what a fantastic spot, good for you, maybe in a few year i can make it that way, Mary..
-
That last picture of brecciated material looks like it will take a nice polish. Hopefully not too many cracks. Looks like an amazing area to explore with probably numerous treasures yet to be found. Look forward to seeing more from your explorations!