OASIS FORUM Post by the Golden Rule. GoldTent Oasis is not responsible for content or accuracy of posts. DYODD.

Maya, thank you very much for the recent postings from

Posted by Equisetum @ 0:19 on August 18, 2018  

your own knowledge and observations, plus the USGS links, all relating to recent volcanic activity near you.  The type of lava that has always intrigued me is pillow lava, especially when it occurs at altitudes as much as 7000 feet above present sea level, unlike the pillow lava that the edge of your island has recently been experiencing when today’s lava flows reach seawater.

I had the good fortune in 1959-60 to take my geomorphology instruction when this subject was being taught at U.B.C. by Bill Mathews.  In the link below, Bill Mathews is mentioned because he is still regarded as an early authority on subglacial volcanos.  It was from Dr. Mathews that I first heard of pillow lava.

In case you are wondering how there can be pillow lava formed several thousand feet above sea level, today’s best documentation is from the  Mount Edziza area of British Columbia, at about 7000 feet above sea level.  In southwestern B.C., also around 7000 feet altitude, pillow lava has also been observed in the Mount Cayley volcanic field of the Garibaldi volcanic belt.  In the case of both Mount Edziza and Mount Cayley, the explanation is that the erupting volcano created lava-dammed meltwater lakes beneath or  near the melting overhead glacial ice.  Pillow lava and pillow tubes developed as lava cooled in the glacial meltwater lakes , just as lava cools beneath seawater.  The link below is a schematic of Mathews’ subglacial volcanism.

 

https://en.wikipedia.org/wiki/Subglacial_volcano

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Post by the Golden Rule. Oasis not responsible for content/accuracy of posts. DYODD.