What are the main types and products of weathering?
There are 3 basic types of weathering. The easiest to understand is mechanical weathering, which produces clasts of rock/mineral which are smaller than the original, and of the same general composition. There are two basic processes: fracturing, which is like a hammer and produces angular clasts; and abrasion, which works like sandpaper and rounds off the rough edges.
Chemical weathering also produces smaller pieces, but of a different chemical composition - the minerals have been changed in an attempt to be more in balance with surface conditions. Chemical weathering occurs more easily in the mafic minerals. Since they are formed at higher temperatures (in accordance to Bowen's Reaction Series) and at relatively low moisture levels, they begin to chemically weather under surface conditions at a faster rate than the more felsic materials. The most common product of chemical weathering is clay.
The third type, biological weathering, really isn't a type of its own. However, the actions of plants (and animals) can and do lead to both mechanical and biological weathering.
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