Sierra Nevada Older than Previously Thought

[Tuff Guy 62]

Came across this article that theorizes that the Sierras' may be much older than previously thought.

Work involved oxygen isotope analysis of clay minerals from old gold rush diggings.

Study indicates that the paleo-Sierra Nevada may be as much as 40 million years old.

Let the arguments begin!!

http://phys.org/news/2015-12-scientists-mystery-sierra-nevada-age.html

 

[Wandering Sagebrush]

Well, now we have the Sierra Geezer range

Regardless of age, they're stunningly beautiful.

Thanks for sharing!

 

[Foy]

The Sierra Nevada and the Cascades: The two principal mountain ranges in the Lower 48 which I've never laid eyes on (excepting from an airliner, which I don't count). I need to do something about that.

Discovering one's range is older than initially thought isn't necessarily a bad thing. We can still treasure them. My "home range" is the Appalachians and they've been folded, faulted, and metamorphosed multiple times since initial deposition/eruption 1.8 billion years ago. Even the most recent edition which we enjoy today was formed 270 million years before present, during the Alleghanian Orogeny.

Thanks for the link TG!

Foy

 

[Vintage62]

Interesting hypothesis, but with all things that involve 'black-box' data (isotopes isolated from clays that are themselves products of weathering), I'd like to see other lines of evidence to either back it up or call it into question. I'll have to review the paper at home to be able to comment much more than that, but I'd certainly want to know the modern elevations of the clay samples that the team collected. Most mining areas up there, as you know, are at much lower elevation than the spine of the range.

Of course, if the Sierra Nevada (or paleo Sierras) were that imposing in the Eocene, that should be reflected in provenance of clastic sediments eroded from the range and deposited downstream. That would be the first thing I would look at - Eocene sedimentary rocks in the region.

Geology = 4-dimensional jigsaw puzzle (and you can work on it outdoors!)

 

[Smokecreek1]

Me I'm lucky, Susanville is bisected by the Cascades on the north and the Sierras on the south-yep right down hw 36. The Modoc/Northwest Plateau just a tad to the NE and I live on the western edge of the Northern Great Basin(high desert). Great geology, lot's of interesting fauna and flora and a long cultural history and one of the main reasons I've been here so long-but not as long as the Sierras ! Where the granite meets volcanic and the fun and life gets interesting!

Smoke