Stanford scientists crack mystery of the Sierra Nevada's age

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Stanford scientists crack mystery of the Sierra Nevada's age

Post by ERIC »

Stanford scientists crack mystery of the Sierra Nevada's age

Recent research by Stanford Earth scientists uses new techniques to shed light on the contentious history of California's iconic mountain range.

BY MILES TRAER
http://news.stanford.edu/news/2015/dece ... 21115.html


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Stanford Earth alum Hari Mix stands high in the Sierra Nevada. New evidence shows the California mountain range is 40 million years old, much older than previously thought.

In science, the simplest questions often prove themselves the most difficult to answer. Questions such as what killed the dinosaurs, or how many fish are there in the oceans took decades to solve or remain unanswered.

One of the biggest questions in the geological history of the western United States is: How old is California's Sierra Nevada? Recent work by a team including Stanford scientists goes a long way to providing an answer, as well as a view into climate history that could assist future climate change projects.

The research, available...

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Re: Stanford scientists crack mystery of the Sierra Nevada's

Post by cslaght »

This is fascinating, and I'm sure some of our geologists would be glad to interject here as well. One question that popped in my mind when reading is the general location of the continent, as in the context of continental drift and, more specifically, latitude, played a role in the climate numbers and the types of climate the Sierra would experience when it was first uplifted.
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Re: Stanford scientists crack mystery of the Sierra Nevada's

Post by giantbrookie »

Let's just say the geoscience researcher whose published views are the most contrary to those of the Stanford group is a Topix member. There is a reference in an earlier post on this thread to a 2013 paper that presents alternative interpretations to isotopic paleoaltimetry.

I guess it is also important to distinguish as to what one is referring to when one refers to the "age" of the range. When the range attained most of its elevation? The two opposing theories are essentially that of no uplift of the range within the last 20 million years versus static or decreasing elevations since >40 m.y. Both sides agree to significant elevations at ca. 40 Ma, especially in the southern Sierra. In other words, both sides agree that streams flowed westward across the northern Sierra from ca. 40 Ma to present meaning that the east was higher than the west, but the difference is that one side proposes that the Sierra, gained a lot of new elevation in the past 20 my (past 3-4 My from north of Yosemite and more than 1/2 of the peak elevation in the northern Sierra versus a 20 my kickoff time for the highest part of the Sierra and perhaps less than 1/2 of the peak elevation added since then), whereas the other proposes the Sierra did not gain any elevation in geologically more recent times. Note that the age of the elevation of the range is a different beast than the age of the rocks---the rocks are much older than this. If we wanted to go back further and say, how far back to we have to go to get to a time when the Sierra Nevada was not elevated at all, it would be ~130 my or so. In other words, depending on one's definition, one could argue that the Sierra was 130 million years old, but the big argument concerns whether or not the Sierra Nevada was given an extra boost of elevation after 20 m.y.
Since my fishing (etc.) website is still down, you can be distracted by geology stuff at: http://www.fresnostate.edu/csm/ees/facu ... ayshi.html" onclick="window.open(this.href);return false;
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Re: Stanford scientists crack mystery of the Sierra Nevada's

Post by cslaght »

Giant Brookie,

I definitely defer to you with the expertise in the matter. I am very curious about this and my very limited knowledge of Geology presupposes many questions with very little answers. I think the dynamic makeup of geological features of the Sierra make this an interesting point as well, as you highlight the age of the rocks has a much different interpretation to the supposed elevation of the range in and of itself. As far as weather patters go, I can imagine the wealth of information would fall east (and maybe south?) of the range to have a further detailed account what the effects range had on localized climate. Though, to me, this proposes other questions as well, specifically in the context of how the Ritter Range, Southern Sierra, and White Mountains really affect how we can interpret it, as they have different geological formations. I am incredibly interested in it, though professionally geology and geography fell second in my academic pursuits so I don't have as strong of a knowledge I'd like to have. I hope my ramblings made sense.
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How old is she really?

Post by maverick »

Professional Sierra Landscape Photographer

I don't give out specific route information, my belief is that it takes away from the whole adventure spirit of a trip, if you need every inch planned out, you'll have to get that from someone else.

Have a safer backcountry experience by using the HST ReConn Form 2.0, named after Larry Conn, a HST member: http://reconn.org
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Re: How old is she really?

Post by cslaght »

I love the fact that one of the photos is from near Yokohl Valley. It's an area that doesn't pop in one's mind to discuss the majesty of the Sierra, but I do love going back there and cresting Blue Ridge and up to Mountain Home (though haven't been all the way up in a very long time).
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Re: How old is she really?

Post by rlown »

A related topic at viewtopic.php?f=27&t=13805 maybe a merge?

And just for fun: https://answersingenesis.org/age-of-the ... the-earth/ New-Earth vs. Old-Earth argument. Guess which side of the coin I'm on.... :unibrow:
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Re: How old is she really?

Post by SSSdave »

I've read quite a few geology books over the years on the range and never liked the theory they rose just 10 million years ago. The granite plutons are Cretaceous and Jurassic in origin so the 10my number meant the plutons were too deep in the crust for much of their existence to affect the surface which seemed to me to be a poor coincidence. Especially since at the western edge in the foothill zone there are rock layers right above the granite that are a continuous sequence down through early Cenozoic. Will be interested in what GB has to add.
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Re: How old is she really?

Post by rlown »

GB did answer in the prior thread at viewtopic.php?f=27&t=13805. Someone should merge these threads...?
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Re: Stanford scientists crack mystery of the Sierra Nevada's

Post by rlown »

thanks for the merge.
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