Subj : ES Picture of the Day 12  2022
To   : All
From : Dan Richter
Date : Wed Oct 12 2022 12:00:36

 EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes
and phenomena which shape our planet and our lives. EPOD will collect and
archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


 Arizona’s China Wall

   October 12, 2022


    TomMc_ChinaWall

   Photographer:  Thomas McGuire

   Summary Author:  Thomas McGuire

   Shown above is China Wall, a rock formation in the  Tonto National
   Forest, north of Scottsdale, Arizona. It forms a broken vertical wall
   nearly a mile long (1.6 km), and about 10 feet high (3 m) and 5 feet
   wide (1.5 m), draped over the summit of  Bronco Butte (satellite
   photo below). It was so-named because of its resemblance to the ruins
   of the  Great Wall of China, which is about two to three times
   larger.

   China Wall is a sill  intrusion of  rhyolite, a relatively common
   igneous rock. Rhyolite has a composition similar to  granite, but
   due to relatively rapid cooling, the crystals are much smaller than
   granite. The China Wall  magma was injected into meta-sedimentary
   rocks that are nearly half as old as Earth itself. Although the layer
   of rock is oriented vertically, it’s inferred that the  sill was
   injected horizontally and the whole regional package was rotated into
   the vertical position by a billion years of  plate tectonic forces.
   With the sparse vegetation found in the U.S. Southwest, bedrock
   exposures often reveal the orientation of the layers.

    TomMc_ChinaWall.jpg2b


   China Wall, Arizona Coordinates: 33.9008, -111.8810


Related EPODs

    Arizona’s China Wall  Fossil Lake’s Legacy at Wyoming’s Fossil
   Butte  Wagon Tracks from the Old West?  First Light on the Circle
   Cliffs Anticline  Mudcracks: Now and Then  Mantling on Utah’s
   Hogback Ridge
    More...

Geology Links

     *  Earthquakes
     *  Geologic Time
     *  Geomagnetism
     *  General Dictionary of Geology
     *  Mineral and Locality Database
     *  Mohs Scale of Mineral Hardness
     *  This Dynamic Earth
     *  USGS
     *  MyShake - University of California, Berkeley
     *  USGS Ask a Geologist
     *  USGS/NPS Geologic Glossary
     *  USGS Volcano Hazards Program

-
   Earth Science Picture of the Day is a service of the  Universities
   Space Research Association.

https://epod.usra.edu
 
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