Fossiliferous limestone

Sample of fossiliferous limestone

Fossiliferous limestone is any type of limestone, made mostly of calcium carbonate (CaCO3) in the form of the minerals calcite or aragonite, that contains an abundance of fossils or fossil traces. 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 overtime to opal and chert, providing the only inferred evidence of bioactivity preserved in limestone.

Fossiliferous limestone is termed biosparite limestone 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.

Examples of small fossils in limestone.

Common rock types

Less fossil bearing types

Geological layers

Locations on Earth

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See also

This article is issued from Wikipedia - version of the Thursday, June 18, 2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.