Fossiliferous limestone

Fossiliferous limestone is a type of limestone that contains noticeable quantities of fossils or fossil traces. If a particular type of fossil dominates, a more specialized term can be used as in "Crinoidal", "Coralline", "Conchoidal" limestone. If seashells, shell fragments, and shell sand form a significant part of the rock, a term "shell limestone" is used.^[1]

The fossils in these rocks may be of macroscopic or microscopic size. The sort of macroscopic fossils often include crinoid stems, brachiopods, gastropods, and other hard shelled mollusk remains.

In some cases, microfossils such as siliceous diatom shells in deposition may convert over time to opal and chert, providing the only inferred evidence of bioactivity preserved in limestone.

Fossiliferous limestone is termed biosparite under the Folk classification of sedimentary rocks.

Lagerstätte are a class of fossil bearing rocks that includes fossiliferous limestone.

Use

Fossils in general provide geologic clues to the environment of deposition, rock formation, and the types of biological activities present at the time. Index fossils are more helpful in providing geologic references or reference markers.

When polished as tiles or slabs, fossil bearing rocks are used as attractive building facades and pavements. They are also carved as ornamental stones, and used in jewelry making.

Common rock types

• Carboniferous limestone
• Coquina
• Coral rag
• Coral sand
• Fossil beach
• Keystone
• Shelly limestone

Less fossil bearing types

• Lithographic limestone
• Marl
• Millstone
• Plattenkalk
• Tufa

Geological layers

Locations on Earth

See also

• List of types of limestone
• Muschelkalk

References

Sources

• Mysore State Department of Mines and Geology (1920). Records, Vol. XVII-1918, Part II. Bangalore: Gevernment Press. Retrieved 2023-12-17.

This page was last edited on 21 February 2024, at 06:51