Columbus Limestone
Encyclopedia
The Columbus Limestone is a mapped bedrock unit consisting primarily of fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

iferous limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

, and it occurs in Ohio, Pennsylvania, and Virginia in the United States, and in Ontario, Canada.

Stratigraphy

The Columbus conformably overlies the Lucas Dolomite in northeastern Ohio, and unconformably overlies other dolomite elsewhere. It unconformably
Unconformity
An unconformity is a buried erosion surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger, but the term is used to describe...

 underlies the Ohio Shale in northwestern Ohio and the Delaware Limestone in eastern Ohio.

Its members include: Bellepoint, Marblehead, Tioga Ash Bed
Marcellus Formation
The Marcellus Formation is a unit of marine sedimentary rock found in eastern North America...

, Venice, Delhi, Klondike, and East Liberty.

Notable Exposures

  • The type section is located in Columbus, Ohio
    Columbus, Ohio
    Columbus is the capital of and the largest city in the U.S. state of Ohio. The broader metropolitan area encompasses several counties and is the third largest in Ohio behind those of Cleveland and Cincinnati. Columbus is the third largest city in the American Midwest, and the fifteenth largest city...

    .
  • The glacial grooves on Kelleys Island
    Kelleys Island, Ohio
    Kelleys Island is both a village in Erie County, Ohio, United States, and the island which it fully occupies in Lake Erie. Originally known as Island Number 6 and later Cunningham Island, it was renamed in 1840 for brothers Datus and Irad Kelley, who were largely responsible for cultivatating the...

     are cut into the Columbus Limestone. It is also quarried
    Quarry
    A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...

     there.
  • An exposure in Ontario is located at Ingersoll, Ontario
    Ingersoll, Ontario
    Ingersoll is a town in Oxford County on the Thames River in southwestern Ontario, Canada. The nearest cities are Woodstock to the east and London to the west....

    .

Fossils

The Columbus Limestone contains brachiopod
Brachiopod
Brachiopods are a phylum of marine animals that have hard "valves" on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, while the front can be opened for feeding or closed for protection...

s, trilobite
Trilobite
Trilobites are a well-known fossil group of extinct marine arthropods that form the class Trilobita. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period , and they flourished throughout the lower Paleozoic era before...

s, bryozoa
Bryozoa
The Bryozoa, also known as Ectoprocta or commonly as moss animals, are a phylum of aquatic invertebrate animals. Typically about long, they are filter feeders that sieve food particles out of the water using a retractable lophophore, a "crown" of tentacles lined with cilia...

ns, mollusks
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...

, coral
Coral
Corals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...

s, stromatoporoids and echinoderms (including crinoid
Crinoid
Crinoids are marine animals that make up the class Crinoidea of the echinoderms . Crinoidea comes from the Greek word krinon, "a lily", and eidos, "form". They live both in shallow water and in depths as great as 6,000 meters. Sea lilies refer to the crinoids which, in their adult form, are...

s).

Due to their mid-continent depositional environment, the fossils are almost free of deformation caused by tectonic activity common in the Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...

.

Brachiopods include Spirifer macrothyris and Brevispirifer gregarius (see Spiriferida
Spiriferida
Spiriferida is an order of extinct articulate brachiopod fossils which are known for their long hinge-line, which is often the widest part of the shell. In some genera it is greatly elongated, giving them a wing-like appearance. They often have a deep fold down the center of the shell...

). The gastropod (snail) Laevidentalhum martinei is present, as well as the crinoid Nucleocrinus verneulli.

Fish fossils have been found in the East Liberty Member ("East Liberty bone bed").

Goniatites
Goniatites
Goniatites is genus of the Goniatitaceae superfamily. They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopuses, and cuttlefish, and more distantly to the nautiloids.-References:* accessed on 10/01/07...

 have been found in the Columbus, including Werneroceras staufferi and Tornoceras eberlei. Another cephalopod species is Goldringia cyclops.

Age

Relative age dating of the Columbus Limestone places it in the Early to Middle Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...

 period.

Economic Uses

The Columbus has been mined for aggregate. Its Calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...

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