MARMET- METEORITES

CLASSIFICATION OF METEORITES

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WHAT IS A METEORITE ?
CLASSIFICATION OF METEORITES
THE COLORFUL WORLD OF THIN SECTIONS
THIN SECTIONS - PART 2
HISTORIC METEORITES 1: Switzerland, Germany, Austria.
HISTORIC METEORITES 2: France: 1492-1841
HISTORIC METEORITES 3: France: 1842-1934
HISTORIC METEORITES 4: England, Ireland, Northern Ireland, Scotland.
HISTORIC METEORITES 5: Italy, Spain.
HISTORIC METEORITES 6: Belgium, Netherlands, Finland, Sweden, Norway.
HISTORIC METEORITES 7: Czech Republic, Slovakia, Poland, Latvia, Ukraine
HISTORIC METEORITES 8: Romaina, Serbia, Croatia, Estonia, Bosnia-Herzeg.
HISTORIC INDIAN METEORITES
PETER MARMET METEORITE COLLECTION - US falls / finds
H. H. NININGER and Canyon Diablo
From MOON and MARS
FAMOUS IRON METEORITES
Libyan Desert Glass
Meteorites from Antarctica
The Allende Meteorite (Mexico)
The Hoba Meteorite (Namibia)
PING PONG IN SPACE
MUNICH 2004
MUNICH 2005
MUNICH 2006
MUNICH 2007
ENSISHEIM METEORITE 2005 part 1
ENSISHEIM METEORITE 2005 part 2
ENSISHEIM METEORITE 2006 part 1
ENSISHEIM METEORITE 2006 part 2
ENSISHEIM METEORITE 2007 part 1
ENSISHEIM METEORITE 2007 part 2
ENSISHEIM METEORITE 2008 Part 1
ENSISHEIM METEORITE 2008 Part 2
Ensisheim Meteorite 2009 part 1
Ensisheim Meteorite 2009 part 2
ENSISHEIM 2010
Ensisheim 2011

Classification of Meteorites
Klassifikation der Meteorite
(Deutscher Text: siehe unten!)

Meteorites are classified into three main groups: irons, stony-irons, and stones. Mineralogically, meteorites consist of varying amounts of nickel-iron alloys, silicates, sulfides, and several other minor phases.

Iron meteorites are characterized by the presence of two nickel-iron alloy metals: kamacite and taenite. Depending upon the percentage of nickel to iron, these subdivisions are classified as: hexahedrites, octahedrites and ataxites.
Octahedrites, the most common type of iron meteorite, exhibit a unique structural feature called the Widmanstatten pattern when etched with a weak acid. This unique crystal pattern is the result of the combination of the two nickel-iron minerals kamacite and taenite being present in approximately equal amounts.

Stony-irons consist of almost equal amounts of nickel-iron alloy and silicate minerals. Although all stony-irons may not be genetically related or have similar composition, they are combined into one group and divided into two subgroups for convenient classification. The Pallasite group is characterized by olivine crystals surrounded by a nickel-iron structure which forms a continuous enclosing network around the silicate portion.

Mesosiderites, on the other hand, consist mainly of plagioclase and pyroxene silicates in the form of heterogeneous aggregates intermixed with the metal alloy.

Stony meteorites are the most abundant of the three meteorite groups and come closest to resembling earth rocks in their appearance and composition. One particular structural feature called chondrules divides the group into two main subgroups:
Chrondrites (with chondrules),
Achondrites (without chondrules).
Many scientists believe that these small, rounded, nearly spherical chondrules may represent the most primitive material in the solar system.

(German version)
Meteorite werden in drei Hauptgruppen unterteilt: Eisenmeteorite, Steineisenmeteorite und Steinmeteorite.

Eisenmeteorite werden bestimmt nach dem Nickel-Eisengehalt und entsprechend als Hexahedrite, Okta-hedrite oder Ataxite bezeichnet.
Die häufigste Gruppe - die Oktahedrite - zeigen, wenn die Oberfläche geätzt wird. das typische Widmann-stättensche Muster.

Steineisen-Meteorite bestehen aus ungefähr gleichen Anteilen von Nickeleisen und Silikaten. Obwohl nicht alle Steineisenmeteorite ähnlich aufgebaut sind, werden sie trotzdem in einer Gruppe zusammengefasst, die in zwei Untergruppen aufgeteilt wurden: in die Pallasite und die Mesosiderite, welche vorwiegend aus Silikaten bestehen.

Steinmeteorite sind die häufig-sten der drei Meteoritengruppen und ähneln in ihrem Aussehen und ihrer Zusammensetzung am meisten dem irdischen Gestein. Anhand der typi-schen Chondren werden Steinmeteorite in zwei Gruppen eingeteilt:
Chondrite (mit Chondren) und
Achondrite (ohne Chondren).
Viele Wissenschafter sind überzeugt, dass diese runden Kügelchen (Chondren) zum ursprünglichsten Material des Sonnensystems gehören!

brahin11.jpg
Beautiful slice of the Brahin pallasite





gibeon11.jpg
Etched slice of the Gibeon iron meteorite

For questions please write to: p.marmet@thinsections.ch