[pct-l] Sierra Volcanic activity

[ned at pacificcrestcustombuilders.com]

So, honorable Strider-san, what is going on around Mammoth? Is that not some form of volcanic activity?

Ned
  ----- Original Message ----- 
  From: bighummel at aol.com 
  To: pct-l at backcountry.net 
  Cc: ned at pacificcrestcustombuilders.com 
  Sent: Friday, August 07, 2009 7:54 AM
  Subject: Re: Northern CA in October


  Ned writes;

  <<<
  Could it be said that the Cascades extend as far south as Mt. Lassen?
  At what point does the northbound hiker leave the Sierra? Is Tahoe the 
  northern terminus? Are the Sierras considered sections F thru K?
  >>>

  Geologically, the "Sierra" as defined by granitic intrusions, may extend a bit north of the Sierra Buttes, nearly to Lassen.   Lassen is the southern-most active volcano in the Cascade system.  

  Now, all of you who have listened to Hacker's and my "Geology of the PCT" talk, who remembers their tectonics and can say why there aren't any active volcanoes south of Lassen? 

  (hint: SAF and "Triple Junction")


  Greg

  "Don't let the bastards drag you down!"