Yosemite Valley: Formed by Graben or Glaciers?

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Discussion Overview

The discussion revolves around the geological formation of Yosemite Valley, specifically whether it was formed by graben (a geological fault) or by glacial processes. Participants explore historical and contemporary perspectives on this topic, examining evidence and theories related to both models.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • Some participants recall a television program suggesting that Yosemite Valley was formed by graben rather than glacial activity.
  • Others point out that there is substantial evidence supporting glaciation as a significant factor in the valley's formation.
  • A participant notes that the graben theory may have been recently revived after being largely dismissed for decades, indicating ongoing debate about its validity.
  • There are features in the valley that some argue could support the graben formation theory.
  • One participant seeks peer-reviewed documentation to support the graben theory, indicating a desire for credible sources on the topic.
  • Another participant references a historical context, mentioning Josiah Whitney's original proposition of fault formation and John Muir's later acceptance of glacial origins, highlighting the evolution of geological theories over time.
  • It is proposed that both normal faulting (graben formation) and glacial erosion could have contributed to the current topography of Yosemite Valley.

Areas of Agreement / Disagreement

Participants express differing views on the primary processes responsible for the formation of Yosemite Valley, with no consensus reached. The discussion reflects ongoing debate and exploration of both the graben and glacial theories.

Contextual Notes

Participants note the historical context of geological theories, including the influence of early geologists and the potential for evolving interpretations based on new evidence. There is an acknowledgment of the limitations of television as an educational medium, which may oversimplify complex geological histories.

D English
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I recall watching a program on TV that said the Yosemite Valley was formed by graben as opposed to being carved out by a glacier.

I wanted to look into it further, but haven't been able to find anything in the first several pages of Professor Google's archives.

Is anyone familiar with this, or know of any links?
 
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Thanks for the reply 256. Yes, read the Wiki, that's how I was able to accurately term "graben".

I haven't been able to find any sites that go into depth on the Yosemite valley being formed by graben.

My query lies in my belief that the television show I saw was a recent production, and seemed to be on the side of the valley being formed by graben and not by glaciation.
 
There definitely is evidence of glaciation.
The graben idea might have been resurrected recently after being dismissed for several decades.
There also seems to be features that point to graben.
 
256bits said:
There definitely is evidence of glaciation.
The graben idea might have been resurrected recently after being dismissed for several decades.
There also seems to be features that point to graben.

Right!

So now I'm looking for peer-reviewed or likewise suitable documentation. I thought the community may know of a repository like arXiv. I couldn't find anything on it in arXiv.

Thanks for humoring me...
 
This is comprehensive from the California Division of Mines about the geological history of the area. Even though dated 1962, it does explain some applicable features,


http://www.nps.gov/history/history/online_books/geology/publications/state/ca/cdmg-bul-182/index.htm


EDIT: Even though the television program may have been recent, since television is an entertainment medium rather than purely educational. Perhaps if could have been discussing the original proposition of Josiah Whitney (California State Geologist in 1860) of fault formation of Yosomite.
John Muir's later predominent glacial origin theory of Yosemite was accepted as being correct.
Since there actually was quite a lot of geological activity in the west coast ( not the same coast as seen today ) over the millions of years, the producers may have focused their attention on that, and sidestepped any later glacial impact in carving out the the area, into 60 minutes of viewership.
 
Last edited by a moderator:
There is, of course, no reason that both normal faulting (to produce a graben) should not have been followed by glacial erosion (to produce the current detailed topography).
 

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