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Re: Aquatic Plants Digest V3 #600
At 03:48 PM 10/24/98 -0400, Wright wrote:
>All this discussion prompted me to see what "arcillite" really is,
>mineralogically.
>Guess what? I can't find it! The closest I can find is a material
>similar to laterite called argillite. It is a silica, alumina,
>iron-bearing material produced by long eons of weathering, just about
>like laterite.
Wright is right. Almost. An academic says Arcillite is a trade name.
NASA says: DESIGNATION: ABSORBER - TURFACE*
COMPOSITION: ARCILLITE (MONTMORILLONITE CLAY) AND CRYSTALLINE SILICA 5
PERCENT
About argillite, U Waterloo (
http://www.science.uwaterloo.ca/earth/museum/rgarden/arg.html ) says:
Cherty Siltstone ( Argillite ) Gordon Lake, Nr.,Sault Ste. Marie. This fine
grained rock formed in a
shallow water environment. Ripple marks, mud cracks and slump structures
can be seen.
--
Dave Gomberg, San Francisco mailto:gomberg at wcf_com
http://www.wcf.com/wcf
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