Mike MalaskaMosaic Canyon, Death Valley National Park.
There's no dissolution geology here, is there?
WRONG
Virtual #geology hike thread.
As you hike up Mosic Canyon, you quickly get to canyon walls made of marble - metamorphisized carbonates. Sometimes only on one side of the canyon.
Here is a detail of the marble outcrop that tells some of the story:
Carbonate muds laid down. Turns to limestone/dolomite. Then heating segegation turns to banded marble (mineral repartitioning).
THEN, microfaulting and little shifts of the banded zone pattern.
Then, tension cracks and infilling.
(Then canyon wall erosion reveals this face.).
Now look at that picture again (repeated here). And look at the microkarren on the surface!
Zoom in to see the fine tiny runnels.
So the last step is exposure then some karst (microkarren) formation.
Not much, but its there.
Here is a picture of an outcrop showing surface karren crossing marble grain boundaries.
So the marble got broken up, then recemented together. (Brecciated).
Notice that the features in the fine karren surface (those little teeny valleys) go right across across the grain boundaries like they don't care.
At least here, that tells us that the karren doesn't care whether it forms in the marble fragment or surrounding marble matrix. Maybe is the same hardness? Or dissolution properties?
Here is just one picture of a section of an outcrop.
There is just so much going on here.
First. Deposition of carbonate muds.
Marbelization.to make abig slab of banded marble.
Then that broke up. Chunks tossed around. Marbelization again.
Then...removal? And now rounded smooth gravels (stream deposit) deposited on top of the marble breccia. (This makes an unconformity.)
Then Lithification of the conglomerate.
Then...erosion reveals this in the canyon wall.
All that from one image.
Now. Same story as above. Maybe this image shows a little better fine detail in the boundary between the lower tan brecciated marble and gray lithified conglomerate.
But also a lot more tiny holes. This section of marble is shot through with tiny conduits. It is porous!
Also, not that the brecciated matble did not get thrown around so much before it "froze" into final position.
Whoo. That's a bit for now. Please enjoy a lizard break.
Zebra tailed lizard.
Richard Hendricks@mike_malaska Is there blue in that upper breccia?