Subj : ES Picture of the Day 06  2022
To   : All
From : Dan Richter
Date : Wed Apr 06 2022 12:01:08

 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.


 Muonionalusta Siderite Sample

   April 06, 2022

    Muonionalusta-siderite-iva

   Photographer:  Thierry Lombry

   Summary Author:  Thierry Lombry

   This photo showcases a specimen of  Muonionalusta  siderite found
   in Sweden in 1906, of which 500 pounds (230 kilograms) were collected.
   The sample above weighs 338 grams and measures 3.2 x 2.6 x 1.1 inches
   or 8.13 x 6.6 x 2.8 centimeters, making its density 7.5 g/cm^3.
   Siderites are  iron meteorites and this sample fell approximately 1
   million years ago. Originating 4.56 billion years ago, this family is
   one of the oldest meteorites.

   This specific specimen contains more than 91%  iron - which explains
   the difficulty in cutting and polishing it - 8.4%  nickel and traces
   of rare elements (0.33 ppm of  gallium, 0.133 ppm of  germanium
   and 1.6 ppm of  iridium) . It is an example of a fine
    octahedrite (Of), the most widespread of the siderites, of group IV
   A. Being a metamorphic meteorite, it formed in the heart of an asteroid
   of 31 to 68 miles (50 to 110 km) in radius that exploded following a
   collision. Crystallization occurs after the metal has melted. Cut,
   polished and acid etched, this siderite sample features the
    Widmanstätten pattern that formed in temperatures between 1000 and
   700 Kelvin. To preserve its quality, this specimen has been treated and
   protected against corrosion since rust would appear within 6 months if
   left exposed.

Related EPODs

    Muonionalusta Siderite Sample  Archive - Mud Cracks near Trona,
   California  Rainbow Pyrite  Archive - Naatsis’aan  Archive -
   Upheaval Dome  Grosvenor Double Arch
    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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