16 Meteorites by Y99Z7tP

VIEWS: 6 PAGES: 55

									      Meteorites



Fragments of the Solar System
• Dedicated to
  Dr. Elbert King
  – First director of
    the Lunar
    Receiving Lab
  – Recovered a
    lot of Allende!!
  – Meteoriticist
                Meteorites
• Meteoroids
  – “small” rocks orbiting in space
• Meteors
  – “rocks” entering the atmosphere and glowing
  – Most are the size of a grain of sand
  – Some are a lot bigger!!!
• Meteorites
  – Rocks from space that have hit the Earth
  Thunderstone of Ensisheim
• 1492
Thunderstone of Ensisheim
       What’s left of it
• What Holbrook
  supposedly
  looked like

 1946
• Famous
  painting of the
  Shikote-Alin
  meteorite on a
  USSR postage
  stamp.
                     Meteorites
• Irons                             iron + nickel

• Stoney Irons
  – Mesosiderites       MES         silicate + iron
  – Pallasites          PAL         iron + silicate (olivine)
• Stoney
  – Chondrites                     silicate + some iron (sometimes)
     • Ordinary Chondrites H, L, LL
     • Carbonaceous Chondrites C, CO, CV, CM, CK
     • Others – Enstatite Chondrites E – Rumruti R
  – Achondrites
     • HED – from Vesta
     • SNC – from Mars
     • ALUN – from the Moon
                 Irons
• Cape York – “discovered” by Peary

 from
 Greenland

 actually
 discovered by
 local Inuit
Irons
Irons
                 Irons
• Witmanstatten Patterns




• Gibeon
               Irons
• Willamette
                    Irons

•                           Hoba – 60 tons




• Campo del Cielo
               Stony Irons
• Mesosiderites - MES
• Silicate based – with a lot of metal running
  through it.

• NWA1879
            Stoney Irons
• Another
  mesosiderite
  -MES
            Stoney Irons
• Mesosiderite   Morristown
               Stoney Iron
• Pallasites
• Iron based – with olivine crystals sprinkled
  through
• Thought to
  be from the
  core-
  mantle
  boundary of
  the parent
  asteroid
   Stoney Iron
Pallasite – lit from behind
        Stoney - Chondrites
• Ordinary Chondrites
  – H (High Metal) – L (Low Metal)
         – LL (Very Low Metal)
• Inside (Brecciated)            Outside (Crusted)




        Probably a L4-5 – this comes from NWA – Morocco
Chondrules / Chondrites
                  Stoney - Chondrites
   • Carbonaceous chondrites
       – Residue from the formation of the Solar
         System – 4.5+ Billion Years old
Murcheson – CM2                   Allende – CV3.2
        Stoney - Achondrites
            Meteorites from Asteroid 4 Vesta

• HED              Howardite




• DAG 844
          Stoney - Achondrites
• HED             Eucrite




• Millbillillie
        Stoney - Achondrites
• HED         Diogenite




• Johnstown
        Stoney - Achondrites
            Meteorites from Mars

• SNC      Shergottite




• Zagami
        Stoney - Achondrites
• SNC

                      DAG 476




               Dhofar 019
      Stoney - Achondrites
            Meteorites from the Moon

• ALUN

• DAG 400
   How do we know they are from
    Mars / the Moon / 4 Vesta??
• Mars: Viking 1 and 2 had soil and atmosphere
  analyzers. The percentages of the elements and
  isotopes are the same as the SNC meteorites –
  and different from others!
• The Moon: Same story – except we have real
  moon rocks to compare them to
• Vesta: Spectroscopy of Vesta indicates it is
  made of HED materials, and no other asteroid is.
  Recent studies show a great crater on Vesta
  where some of these materials must have been
  ejected from.
     How to Study Meteorites
• What does it look like (big picture)
• What does it look like (microscope)
• What elements are in it (chemistry and
  microprobe)
• What isotopic ratios are there (microprobe)
• Where did it come from (compare to
  asteroids and planets)
• How did it fall (distribution)
    Meteorites / Meteorwrongs
• Meteorites are not hot when they hit the earth!
• Almost all meteorites are magnetic!
• Almost all meteorites have some visible metal
  (though sometimes only a little).
• Most meteorites are denser than local rocks.
• Meteorites don’t have holes/bubbles in them.
• For real analysis you have to take it to an expert
     How to Study Meteorites
• Thin Sections –
     The coolest way to look at meteorites is
  in “thin section”. Take a thin slice of the
  rock, glue it to a microscope slide and
  grind/polish it until it is 30 micrometers
  thick.
     You can then look at it under a
  “petrographic microscope” with crossed
  polarizing filters. The colors tell you the
  minerals!
Eucrite   Enstatite
Richfield LL3.7
Pultusk
• SNC
Some chondrules in thin section
         Eucrite thin section
• Looks a lot like Kilauea basalts!
Apollo 17 Basalt
Apollo 12 Basalt
       Impact!!!
• When a Big rock hits – 50
  meters or more – it can make
  a rather big hole in the
  ground!!!!
Meteor Crater
Wolf Creek
Lake Manicoagan
Chixilub
Brent Crater
Pretoria “Saltpan”
Sudbury + Lake Wanapitei
               Disclaimer
Aloha
  I put together these power points for use in
  my science classes.
  You may use them in your classes.

 Some images are public domain, some
 are used under the fair-use provisions of
 the copyright law, some are mine.
 Copyright is retained by the owners!
Ted Brattstrom

								
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