 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.


 Autumn on Laramidia’s Ancient Shore

   November 26, 2020

    Autumn on Laramidia’s Ancient Shore

   Photographer:  Ray Boren
   Summary Author:  Ray Boren

   During the  Late Cretaceous Period —  before the rise of North
   America’s Rocky Mountains, and  before the Colorado Plateau emerged
   to geologically dominate the  Four Corners region of Arizona, Utah,
   Colorado and New Mexico — a vast  Western Interior Seaway covered
   much of the continent’s center, dividing it into two landmasses. The
   big islands have come to be called  Appalachia (to the east) and
    Laramidia (on the west).

   A cliffy portion of the lithified western shore of that inland sea
   stretches across the background of the autumn-splashed photograph seen
   above taken along  State Road 14, a scenic byway in upper  Cedar
   Canyon above Cedar City, Utah. The shimmering leaves of  Utah’s
   state tree, the  quaking aspen ( Populus tremuloides), are
   revealing their inherent yellow pigments. Due to autumn’s chillier
   temperatures and declining daylight hours, they have ceased producing
    chlorophyll, which tints the leaves green in spring and summer.

   Sediments eroding from now-vanished mountain ranges to the west — on
   Laramidia which stretched from what is today Mexico to Alaska, and
   which gets its name from Laramie, Wyoming — were deposited in rivers,
   lakes and swamps along the  seaway 66-100 million years ago. These
   transformed over time into Cedar Canyon’s tan-to-brown, cliff-forming
   sedimentary  Straight Cliffs ( Tibbet Canyon Member) and
    Wahweap formations. These are also the  oldest rocks in
    Cedar Breaks National Monument, just up the road, along what is
   today the edge of the  Colorado Plateau’s western  Markagunt
   Plateau. Photo taken October 15, 2020.

   Photo Details: Camera NIKON D3200; Exposure Time 0.0020s (1/500);
   Aperture ƒ/11.0; ISO equivalent 400; Focal Length (35mm) 30
     * Cedar Canyon, Utah Coordinates:  37.59442, -112.91643

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Geology Links

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

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

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