Subj : ES Picture of the Day 06  2022
To   : All
From : Dan Richter
Date : Tue Sep 06 2022 12:01:18

 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.


 Wagon Tracks from the Old West?

   September 06, 2022


    Glacial striations

   Photographer:  Brian Sauls
   Summary Author:  Brian Sauls
   No, these aren’t wagon tracks from the Old West. They’re  glacial
   striations, or grooves, that were caused by abrasion from rock
   fragments embedded in the base of an  alpine glacier that once
   flowed in a valley near north-central Colorado’s  Green Mountain
   Reservoir. These striated and polished rocks consist predominantly of
    migmatite, which is an igneous/metamorphic rock exhibiting
   alternating bands of light and dark-colored minerals that formed
   approximately 1.8 billion years ago, during the  Precambrian Era.
   They have the appearance of a marble cake and are well exposed due to
   the relatively recent glacial erosion. Based on the  orientation of
   the grooves, one can determine the direction that the glacier flowed.
   Photo taken in the summer of 1981.
   Photo details: Nikon FM camera; Vivitar 24mm f/2.0 lens; Kodak slide
   film; digitized with Kodak slide scanner.


   Green Mountain Reservoir Colorado Coordinates: 39.798056, -106.349444

Related EPODs

    Wagon Tracks from the Old West?  First Light on the Circle
   Cliffs Anticline  Mudcracks: Now and Then  Mantling on Utah’s
   Hogback Ridge  Dendrite Inclusion in Opal  New Eddystone Rock
    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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