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skcreidc
Social climber
SD, CA
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Sep 12, 2017 - 06:27pm PT
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Unique stuff Fritz! Please bear with me and my shitty cell phone shots.
First, some precambrian Belt Sequence from Montana. It's amazing how 1 billion year old sediments can look so fresh, relatively speaking.
This next is an example of flasier bedding.
Both of these structures can be used to tell top from bottom, tho assymetric ripples tend to be a slam dunk on that.
Last are salt crystals in mudflat deposits. all three of these sediments are from pretty shallow water deposits, with the ripple marks showing some life tracks.
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L
climber
Tiptoeing through the chilly waters of life
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Sep 12, 2017 - 06:36pm PT
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These just sort of belonged together....
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skcreidc
Social climber
SD, CA
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Sep 12, 2017 - 07:56pm PT
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Early Cambrian trilobite death assemblage in shale.
Actually, more accurate to say molting assemblage. Latham Shale, the facies equivalent to the Bright Angle Shale.
Nice balancing act L.
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hooblie
climber
from out where the anecdotes roam
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Sep 12, 2017 - 08:47pm PT
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i came upon a sparsely treed clearing up in the park, nice grazing for the elk.
just below the thin topsoil lurked kaibab limestone of which this is an example.
no bony exposure broke through the grass, nothing to discourage a guy
with a lawn mower as long as a buddy ran ahead and lifted the occasional loaf size rock.
those rocks were almost evenly spaced as if in array, though there were a few close pairs.
i pondered what the mechanism might be to produce the scene and nothing from the geologic playbook seemed to fit.
i did come up with a hypothesis ... when the roots of trees encounter slabby layers in the search for cracks to penetrate,
they grasp chunks that are revealed when a blowdown lays them down, and there is a size sorting function at work,
nothing too huge and smaller chunks don't get the full wrap treatment or are subsumed into the soil process.
as long as the tree takes to disappear completely, the rock can out last it to mark the spot.
so there's a legacy left behind of levering and plucking by trees long gone ... i spoze!
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Gnome Ofthe Diabase
climber
Out Of Bed
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Sep 25, 2017 - 06:50am PT
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A Monday morning perusal of the fine specimen
Led me to feel the need
More not following contrivance; niether a Tuesday post or crystalline beauty
this would be the less fetching version The Rock Is from an area Hy??? something-or-other in India. this un-enhanced snap was a placeholder
I've added the much better version, cropped & brightened.
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L
climber
Tiptoeing through the chilly waters of life
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Sep 26, 2017 - 05:29pm PT
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One of my favorites:
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Craig Fry
Trad climber
So Cal.
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Sep 26, 2017 - 07:27pm PT
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Afghanistan Scapolite
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mouse from merced
Trad climber
The finger of fate, my friends, is fickle.
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Sep 27, 2017 - 03:13am PT
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Fritz
Social climber
Choss Creek, ID
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Topic Author's Reply - Oct 3, 2017 - 07:27am PT
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Thanks folks for sharing such fine rocks!
A FB friend posted about this find today:
A gigantic cave of crystals has been discovered in an old silver mine in Spain.
It occupies a space of 10.7 m³ (8 m long by 1.8 m wide by a 1.7 m average high) and is located at a depth of 50 m in the Pilar de Jaravía lead mine, in the Sierra del Aguilón, in the municipality of Pulpí, coinciding with the sea level, 3 km from the coast.
The geode, which is eight metres (26ft) long and crammed full of gypsum prisms, has been put under police guard to prevent souvenir hunters from raiding the extraordinary natural phenomenon.
The geologist who announced the find, Javier Garcia-Guinea, wants to turn the site into a tourist attraction.
He said that up to 10 people could sit inside the geode - an object normally small enough to hold in your hands.
Read more at http://www.geologyin.com/2016/10/enormous-crystal-geode-discovered-in.html#h1zauVmRMCOte834.99
Here's some photo info on the find.
I found Gypsum crystals as a teenage rockhound along the Snake River west of Hagerman, ID. They were eroding out of clay formations that had been deposited into what Geologists now call Lake Idaho, back a million or so years ago.
Here's one I hung onto.
In the 1990's I found nicer translucent yellowish Gypsum crystals near I-90 west of Gilette WY.
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Nick Danger
Ice climber
Arvada, CO
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Here is a mono and a metate I found far up Paintbrush Canyon on the Nevada Test Site.
The mono is composed of densely welded rhyolite tuff and the metate is composed of weakly welded quartz latite tuff.
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Nick Danger
Ice climber
Arvada, CO
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Oct 10, 2017 - 07:42am PT
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Nonwelded ash flow and ash fall tuffs of the Timber Mountain Group, northern Crater Flat, NV.
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Craig Fry
Trad climber
So Cal.
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Oct 10, 2017 - 06:00pm PT
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Afghanistan tourmaline
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hooblie
climber
from out where the anecdotes roam
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Oct 10, 2017 - 06:58pm PT
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Fritz
Social climber
Choss Creek, ID
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Topic Author's Reply - Oct 24, 2017 - 07:40am PT
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Great rocks folks! More please.
Heidi & I did some tree-trimming last summer that opened up the view from our front porch of the basalt cliffs above Choss Creek.
Our enjoyment of fall alpinglow on those cliffs has been greatly enhanced, as well.
I had to refresh my memory about the origin and significance of the cliffs. They come from lava flows that spewed out of Mckinney Butte, about 25 miles northeast of us.
Curiously, the lava flows are collectively named the Mckinney Basalt flows. They date to the late Pleistocene Era, just a little earlier than the Lake Bonneville Flood that happened about 14,500 years ago.
The Mckinney Basalt flows dammed the Snake River about 4 - 6 miles below Choss Creek & a new 450' deep lake lasted long enough for substantial amounts of clay to be deposited in this area.
Then, after the lake had mostly drained when the Snake River cut through weaker formations south of Bliss, the Lake Bonneville flood rearranged the clays, gravels, & large rocks of this valley with flows up to 33,000,000 cubic feet per second.
This canyon was once again briefly filled with water, then again, the Snake River flowed normally until whitey started daming it & destroyed the Salmon Runs starting with Swan Falls dam south of Boise in 1901.
On the map below, the Pillow lava was caused by contact with Snake River water.
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hooblie
climber
from out where the anecdotes roam
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Oct 24, 2017 - 09:22am PT
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fascinating sequence you're describing fritz.
are those silt clays what makes for good potato dirt or maybe aeolian deposits?
hadn't thought of fresh water pillow lava - or snagging poached salmon right outta the drinkanyway, there's a rock ... right on top of that other rock
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Wayno
Big Wall climber
Seattle, WA
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Oct 24, 2017 - 09:33am PT
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the Lake Bonneville Flood that happened about 14,500 years ago.
I read that there was more than one of those events. Could you imagine being a witness and survivor to one of those floods. Yikes.
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hooblie
climber
from out where the anecdotes roam
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Oct 24, 2017 - 07:40pm PT
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this stone was rendered bronze by sunlight through the plume of a nearby prescribed burn
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Reilly
Mountain climber
The Other Monrovia- CA
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Oct 24, 2017 - 07:43pm PT
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You might get yer feet wet gettin' to it.
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Craig Fry
Trad climber
So Cal.
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Oct 25, 2017 - 07:39am PT
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My memory stick just broke, so the photos of the Pet. Wood haul with have to wait until I re-edit them.
I do have these as filler
Some quartz
Amethyst
And my new collections of Pargasite (green) and Richterite
I just picked up a sweet cut piece of Richterite
talk about rare!
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