Al,
thanks for the posts. i'll be ordering Bagnal's book next. i'm also
collecting information on mineralology and earth science to get up to speed
with the rest of the list. i've been wondering, if or more likely when,
we're on the Moon, Mars and beyond, will we find meteorites from earth?
will they be similiar in composition to the meteorites found on earth? how
will the lack of atmosphere--no ablation, etc--affect them? would an iron
meteorite on the moon, if it exists, be essentially the same as terrestial
iron? if these are stupid questions, let me know. i'm new to all this and
freely admit to knowing nothing. hope you all are enjoying the holiday
weekend.
thanks for your time
susan patton
----- Original Message -----
From: "AL Mitterling" <[EMAIL PROTECTED]>
To: "MeteoriteList" <meteorite-list@meteoritecentral.com>
Sent: Monday, July 04, 2005 7:48 AM
Subject: [meteorite-list] The Classification Of Meteorites
To All,
There has been a request for information on the classification scheme of
Meteorites. I have a number of sources that tell about this and no doubt
there are websites that may tell a lot more. Anyone that can shed more
light please let me know. Also someone may have a book I don't that could
help out.
Part One.
My sources says that the first attempt to classify meteorites began in
1840's and were based on structural and chemical differences. Keep in mind
that sometimes chemical and geological terms are used to describe the same
thing and complicate or confuse things a bit. One early scientist was Paul
Partsch, the curator of the Vienna collection of meteorites who first
attempted a classification scheme. He separated the stones from the irons.
He separated the Irons into dense, compact, and some which contained stony
material in their structure. The stones were divided up into normal and
anomalous types with the normal being broken down into magnesium-rich and
magnesium poor groups.
Then in the mid 1900th century a Charles U. Shepard attempted to
categorize meteorites using his own classification system. Like Partsch he
had two main categories of stony and iron types. He subdivided the stony
material into trachytic, trappean, and pumice like and the irons were
classified into malleable homogeneous and malleable heterogeneous, and
brittle. Shepard's system however was flawed with the fact that some of
the specimens contained in his collection were not of meteoritic origin.
A third person who worked on a classification system at the same time
Sheperd had was A. Boisse. He had an advantage over Shepard's system by in
the fact he based his specimens on petrographical and density factors. So
he grouped meteorites into stony, iron and uncompacted material. Stony's
were further divided up into magnetic and non-magnetic types. Boisse's
system suffered from the flaws that in that day and age it was thought
that some meteorites left gelatinous matter after the fall, color
rainwater and snow, and powders.
A fourth attempt was made by Carl von Reichenbach in 1859 who had a long
running dispute with the Vienna curator (guess there was meteorite fights
back then too :-) He measured the nickel iron content but noted that a
chemical competition would have been better. He found few supporters for
his system due to his personality and flaws in his system.
Source: Philip M. Bagnal's excellent book "The Meteorite and Tektite
Collector's Handbook"
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