cool el cap graphic

[ivan]

courtesy of those national geographic types

 

[Otto]

Now that is wild. Thanks for sharing it.

[ivan]

i had no idea el cap was the base of an ancient volcano?

[ScaredSilly]

i had no idea el cap was the base of an ancient volcano?

 

I learned long ago that Yosemite is the remnant of a batholith system (granite is crystallized from magmas) but I have never heard that is was under a volcano. It would be interesting to know how the author purports this notion as to my knowledge there is no evidence of caldera.

[rob]

but I have never heard that is was under a volcano. It would be interesting to know how the author purports this notion as to my knowledge there is no evidence of caldera.

 

The article talks about that

 

That's because the weaker rock that surrounded the core of the ancient volcano eroded away, leaving the central plug, which is harder granite, exposed.

 

i.e. the caldera from 100 million years ago (and surrounding volcanic material) is long since gone

[ScaredSilly]

i.e. the caldera from 100 million years ago (and surrounding volcanic material) is long since gone

 

It has been a long time since I have cracked any geology books but my understanding is the Sierra Nevada Range is a batholith which are magna intrusions that did not reach the surface. While some magma did reach the surface such as Devil's Post Pile it was not from a volcano.

 

If there was a volcano I would expect some evidence such as what is seen at Yellowstone.

 

 

[ivan]

 

If there was a volcano I would expect some evidence such as what is seen at Yellowstone.

 

well, there are millions of tourists everywhere