Friday, May 11, 2012

UTAH AMETHYST AND GEORGE CLOONEY

BIG ROCK CANDY MOUNTAIN, MARYSVALE, UTAH.  PHOTO COURTESY OF RAY BOREN AND NASA'S EARTH SCIENCE DIVISION

One of my favorite movies is a loopy flick entitled Brother Where Art Thou directed by those talented brothers, Joel and Ethan Coen, in 2000—a great film for an interesting year, Y2K.  The movie had many memorable scenes and some fantastic music including the song Big Rock Candy Mountain:
Oh the buzzin’ of bees in the cigarette trees
and the soda water fountain,
at the lemonade springs where the bluebird sings
on the Big Rock Candy Mountain.  
 

Hearing the song always reminds me of a student field trip in Utah to a pile of volcanic rocks near the town of Marysvale. The most “famous landmark” of these volcanics is, get ready, Big Rock Candy Mountain.  So, in the "which came first game", I was able to learn that the song is some sort of a depression-era folk tune attributed to Harry McClintock (~1928) and recorded by several other artists including Burl Ives and Tex Ritter.  Our instructor told us that members of the local population placed a hand-made sign near the mountain proclaiming it as Big Rock Candy Mountain and the name stuck.  Today it is a tourist attraction—and an area of interesting geology. 

The area around Marysvale (Piute County, south-central Utah) is dominated by Oligocene to early Miocene volcanic rocks (27 Ma to 19 Ma) associated with a large stratovolcano complex complete with calderas (Hintze, 2005) ---similar in many ways to the current Cascade volcanoes of Washington and Oregon.  The volcanic pile is composed of drab-gray debris flows, lava flows, ash fall tuffs, and pyroclastic flows (ignimbrites).  The brightly colored volcanic rocks at Big Rock Candy Mountain are the result of percolating hot magmatic waters bleaching the normally dark volcanic rocks and leaving behind red, orange and yellow iron oxide stains (Hintze, 2005).
Topaz-bearing volcanic rhyolites (extrusive igneous rocks, rich in silica) in Utah are perhaps best known from the Thomas Range in the western part of the state.  These rhyolites have produced the famous topaz crystals of Topaz Cove, and some other interesting minerals (see blog post on 1 March 12)

Similar rhyolite flows are present in the Marysvale area and have produced some of the same semi-rare minerals such as bixbyite and pseudobrookite, but not the nice topaz crystals.  To make up for the absence of large topaz crystals the rhyolite at Marysvale gives up beautiful, terminated, water-clear, purple-tinged, quartz crystals.  The crystals are lithophysal in nature and collectors must bang on the rhyolite with crack hammers to locate the cavities.  The collecting area is on BLM land (I think but make certain you check with the local office) about 3 miles north of town on US 89 and then west on a gravel road.

mike
PURPLE TINGED QUARTZ CRYSTALS (AMETHYST) IN A RHYOLITE CAVITY; AT MARYSVALE, UTAH.  FIELD OF VIEW ~3 CM. WIDE.



REFERENCES CITED
Hintze, L. F., 2005, Utah's Spectacular geology; How It Came To Be: Department of Geology, Brigham Young University, Provo.

FROM THE FILM
(Nothing to do with amethyst but my favorite quote; warped mind?)
MOVIE SCENE
Delmer, Pete and Everett sitting around a campfire "enjoying" dinner.
  
DELMAR: Care for some gopher? 
EVERETT (George Clooney): No thank you, Delmar. One third of a gopher would only arouse my appetite without bedding it down.
DELMER; Oh, you can have the whole thing. Me and Pete already had one apiece. We ran across a whole... gopher village. 

POST SCRIPT
So the question in my mind, and probably only in mine, is just exactly what were Delmer and Pete really eating down there in rural Mississippi in 1937?  Gopher--that much we know.  But "gopher" is sort of a generic term like "Coke" referring to just about any soft drink.  In the Midwest "gopher snakes" refer to Bull Snakes (Pituophis catenifer).  Gopher Tortoises (Gopherus polyphemus) are "land turtle" found in the southeastern U.S.  But, most people think of a "gopher" as some little furry creature that burrows into the ground.  And, in fact, there is a family of rodents known as the Geomyidae that are the Pocket Gophers.  In the movie, it was obvious the little animal roasting over the fire on the skewer was a small mammal, about the size of a Pocket Gopher, so count out the tortoises and snakes.  And, unfortunately, the Pocket Gophers since their range does not include Mississippi!  The roasting dinner was too small for a Woodchuck (Marmota monax) and too big for any of the "mouse" species found in the state.  The Eastern Woodrats (Neotoma floridans) might fit the size bill; however, I have never heard these animals called "gophers".  That leaves the Eastern Chipmunk (Tamias striatus), a furry little burrowing rodent, as the best suspect; but, it seems somewhat small compared to the roasting animal!  And, have you ever tried to catch a chipmunk?  Oh well, life goes on.
A MINNESOTA GOLDEN GOPHER---THE "REAL THING", AND FANS OF THE UNIVERSITY OF MINNESOTA BASKETBALL TEAM.  PHOTO COURTESY OF U OF M.


FROM THE FILM