Post by 1dave on Nov 11, 2018 13:29:27 GMT -5
I was Google Earthing along, just minding my business, when out of a purple and orange colored sky
Flash! Bam! AllikaZAM! Cove mountain popped into view!
Is it an impact crater, a volcano?
No, and no. - well, kind of no.
It's an eroded Laccolith. And Utah was invaded by a bunch of them!Laccolith - History and Etymology for laccolith: Greek lakkos pond, reservoir + lith a combining form meaning “stone” ( acrolith; megalith; paleolith )
a mass of igneous rock, typically lens-shaped, that has been intruded between rock strata causing uplift in the shape of a dome.
a mass of igneous rock, typically lens-shaped, that has been intruded between rock strata causing uplift in the shape of a dome.
Laccolith exposed by erosion of overlying strata in Montana
Just a few miles south of Cove Mt. is the Pine Valley Laccolith -
the LARGEST laccolith in the US, and possibly the world!
"So, like, man, where did they come from?"
I'm glad you asked. The answer can be found in m-242
ugspub.nr.utah.gov/publications/geologicmaps/30x60quadrangles/m-242.pdf
200 million years ago Pangea broke up and North America was pushed on top of the lumpy Pacific Ocean Plate.
23 million years ago some of those melting lumps began bobbing up under Utah -
Cove Mt., Iron Mt. Granite Mt., Desert Mound, Three Peaks, The BIG one - Pine Valley, The Henry Mts., etc.
ugspub.nr.utah.gov/publications/geologicmaps/30x60quadrangles/m-242.pdf
200 million years ago Pangea broke up and North America was pushed on top of the lumpy Pacific Ocean Plate.
23 million years ago some of those melting lumps began bobbing up under Utah -
Cove Mt., Iron Mt. Granite Mt., Desert Mound, Three Peaks, The BIG one - Pine Valley, The Henry Mts., etc.
-("Laccolith" is correct. "LOCCOLITH" is a typo.)
1. the molten blob starts feeling it's way up through cracks until it reaches it's buoyant level.
2. the rest of the blob floats up to join the level - this forces the levels of rock above it to bow up - like blowing air into a balloon.
3. Rocks begin sliding off the sides.
4. because of release in pressure, volcanic eruptions may begin around the edges of the laccolith.
