Page 177 - Petrology of Sedimentary Rocks

Primary Dolomite Intramicrudite, ili:Dr). Instead of “Primary Dolomite Micrite”
the term “Dolomicrite” may be used.

2. Upper name in each box refers to calcirudites (median allochem size larger than
l.Omm), and lower name refers to all rocks with median allochem size smaller
than 1.0 mm. Grain size and quantity of ooze matrix, cements, or terrigenous
grains are ignored.
3. If the rock contains over IO percent terrigenous material, prefix’Sandy”, “Silty”, or
“Clayey” to the rock name, and “Ts”, “Tz”, or “Tc” to the symbol depending on
which is dominant (e.g. Sandy Biosparite, Tslb:La, or Silty Dolomitized Pelmicrite,
Tzllp:DLa). Glauconite, cellophane, chert, pyrite, or other modifiers may also be
prefixed.

4. If the rock contains other allochems in significant quantities that are not
mentioned in the main rock name, these should be prefixed as qualifiers
immediately before the main rock name (e.g. Fossiliferous Intrasparite, Oolitic
Pelmicrite, Pelletiferous Oosparite, or lntraclastic Biomicrudite). This can be
shown symbolically as Ii(b), lo(p), lib(i), respectively.

5. If one or two types of fossils are dominant, this fact should be shown in the rock
name (e.g. Pelecypod Biosparrudite, Crinoid Biomicrite, Brachiopod-Bryozoan
Biospari te, etc.).

6. If the rock was originally microcrystalline and can be shown to have recrystal-
lized to microspar (5 to IO microns, clear calcite) the terms “microsparite”,
“biomicrosparite” etc. can be used instead of “micrite” or “biomicrite”.

7. Specify crystal size as shown in the examples.

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