Subj : ES Picture of the Day 10  2022
To   : All
From : Dan Richter
Date : Sun Apr 10 2022 12:01:14

 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.


 Archive - Glacial Evidence in Central Park

   April 09, 2022

    6a0105371bb32c970b01b7c6def3d2970b

   Every weekend we present a notable item from our archives.

   This EPOD was originally published on September 25, 2014.

   Photographer:  Bruce Gervais
   Summary Authors:  Bruce Gervais;  Jackie Phillips

   There's ample evidence of  New York City’s glacial history
   throughout  Central Park. The top photo shows two  glacial
   erratics. These large boulders were transported by moving ice at the
   height of the  Wisconsin glaciation, around 20,000 years ago. During
   this time the  Laurentide ice sheet covered what is now New York
   City to a depth of about 1,000 ft (300 m). As the ice sheet flowed over
   the landscape it smoothed the  bedrock through  abrasion and
   plucked fragments of rock from the ground. These plucked fragments were
   incorporated into the base of the moving ice and transported by it.
   After the ice sheet melted, some 12,000 years ago, many fragments were
   scattered throughout the landscape.

    Nycglacialrock2

   The lower photo shows an elongated asymmetrical landform called a
    roche moutonnee. The axis of roches moutonnees indicates the
   direction of ice flow. In this photo, the ice flowed from left to
   right. These landforms are ubiquitous in the park and were cleverly
    incorporated into its  design. Photo taken on July 22, 2014.

   Photo details: Top - Camera Maker: Panasonic; Camera Model: DMC-TS3;
   Focal Length: 4.9mm (35mm equivalent: 28mm); Aperture: f/3.3; Exposure
   Time: 0.0063 s (1/160); ISO equiv: 100. Bottom - same except: Focal
   Length: 8 mm; Aperture: f/4.5; Exposure Time: 1/80 s; ISO equiv: 160.
   Photo stitch program: Microsoft ICE.
     * Glacial Erratic, Central Park Coordinates: 40.769358, -73.975933

Related EPODs

    Archive - Glacial Evidence in Central Park  Muonionalusta
   Siderite Sample  Archive - Mud Cracks near Trona, California
    Rainbow Pyrite  Archive - Naatsis’aan  Archive - Upheaval
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    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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