The Pipe Creek Sinkhole near Swayzee in

Grant County, Indiana Grant County is a county in central Indiana in the United States Midwest. At the time of the 2020 census, the population was 66,674. The county seat is Marion. Important paleontological discoveries, dating from the Pliocene epoch, have been m ...

, is one of the most important

paleontological Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

sites in the interior of the eastern half of

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. It is preserved because it was buried by

glacial till image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

. Uncovered in 1996 by workers at the Pipe Creek Junior

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

quarry A quarry is a type of open-pit mining, open-pit mine in which dimension stone, rock (geology), rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some juri ...

, the

sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are also known as shakeholes, and to openings where surface water ...

has yielded a diverse array of

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s from the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided b ...

, dating back five million years. Discoveries have been made there of the remains of

camelid Camelids are members of the biological family (biology), family Camelidae, the only currently living family in the suborder Tylopoda. The seven extant taxon, extant members of this group are: dromedary, dromedary camels, Bactrian camels, wild Bac ...

bear Bears are carnivoran mammals of the family (biology), family Ursidae (). They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats ...

beaver Beavers (genus ''Castor'') are large, semiaquatic rodents of the Northern Hemisphere. There are two existing species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers are the second-large ...

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

snake Snakes are elongated limbless reptiles of the suborder Serpentes (). Cladistically squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales much like other members of the group. Many species of snakes have s ...

turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...

s, and several previously unknown

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

s. Two fish

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

, bullhead (''

Ameiurus ''Ameiurus'' is a genus of catfishes in the family Ictaluridae. It contains the three common types of bullhead catfish found in waters of the United States, the black bullhead (''Ameiurus melas''), the brown bullhead (''Ameiurus nebulosus''), a ...

'') and sunfish (''

Centrarchidae Centrarchidae, better known as sunfishes or centrarchids, is a family of freshwater ray-finned fish belonging to the order Centrarchiformes, native only to North America. There are eight universally included genera within the centrarchid famil ...

''), have also been found there.

Origin and importance

The Pipe Creek Sinkhole preserves an ancient

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

. It was created by the collapse of a limestone

cave Caves or caverns are natural voids under the Earth's Planetary surface, surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance undergrou ...

in a

Silurian The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of t ...

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

formation. That left a steep-sided depression about long, wide and deep. When water collected in the depression, it became the

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

of the plants and animals whose remains were preserved there when the sinkhole was buried by

glacial A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

outwash An outwash plain, also called a sandur (plural: ''sandurs''), sandr or sandar, is a plain formed of glaciofluvial deposits due to meltwater outwash at the terminus of a glacier. As it flows, the glacier grinds the underlying rock surface and c ...

and

till image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

during the

Pleistocene Epoch The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

, two million to 11,000 years ago. While the

ecology Ecology () is the natural science of the relationships among living organisms and their Natural environment, environment. Ecology considers organisms at the individual, population, community (ecology), community, ecosystem, and biosphere lev ...

of the Pliocene in North America is well-known from fossil discoveries in other places, notably

coast A coast (coastline, shoreline, seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, su ...

al sites, the Pleistocene glaciers destroyed or scattered most of the fossil remains in the continent's interior. The Pipe Creek Sinkhole, however, was ''buried'' by the glaciers and the debris they left, making it the only known Pliocene example in the central part of the eastern half of the continent.

The sinkhole's ecology

The ancient wetland was home to a large and dense plant and animal

population Population is a set of humans or other organisms in a given region or area. Governments conduct a census to quantify the resident population size within a given jurisdiction. The term is also applied to non-human animals, microorganisms, and pl ...

that includes both

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

and extant forms. The

climate Climate is the long-term weather pattern in a region, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteoro ...

was warm and temperate, but somewhat dry, possibly supporting a grassland-forest transitional zone. The preserved

vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

fauna Fauna (: faunae or faunas) is all of the animal life present in a particular region or time. The corresponding terms for plants and fungi are ''flora'' and '' funga'', respectively. Flora, fauna, funga and other forms of life are collectively ...

are dominated by aquatic species, particularly

leopard frog Leopard frog is a generic name used to refer to various species in the true frog genus Lithobates. They all have similar coloration: brown or green with spots that form a leopard pattern. They are distinguished by their distribution and behaviora ...

s, which are still common throughout the United States.

Mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

ian finds include an early

rhinoceros A rhinoceros ( ; ; ; : rhinoceros or rhinoceroses), commonly abbreviated to rhino, is a member of any of the five extant taxon, extant species (or numerous extinct species) of odd-toed ungulates (perissodactyls) in the family (biology), famil ...

(''

Teleoceras ''Teleoceras'' (Greek: "perfect" (teleos), "horn" (keratos)) is an extinct genus of rhinocerotid. It lived in North America during the Miocene and Pliocene epochs during the Hemingfordian to the end of Hemphillian from around 17.5 to 4.9 million ...

'', possibly from the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

epoch),

canids Canidae (; from Latin, ''canis'', "dog") is a biological family of caniform carnivorans, constituting a clade. A member of this family is also called a canid (). The family includes three subfamilies: the Caninae, and the extinct Borophaginae ...

peccaries Peccaries (also javelinas or skunk pigs) are pig-like ungulates of the family Tayassuidae (New World pigs). They are found throughout Central and South America, Trinidad in the Caribbean, and in the southwestern area of North America. Peccari ...

and short-faced bear. Backed by a grant from the

National Science Foundation The U.S. National Science Foundation (NSF) is an Independent agencies of the United States government#Examples of independent agencies, independent agency of the Federal government of the United States, United States federal government that su ...

, researchers from the

Indiana State Museum The Indiana State Museum is a museum located in Downtown Indianapolis, downtown Indianapolis, Indiana, United States. The museum houses exhibits on the science, art, culture, and history of Indiana from prehistoric times to the present day. His ...

and several universities substantially completed

field work Field research, field studies, or fieldwork is the empirical research, collection of raw data outside a laboratory, library, or workplace setting. The approaches and methods used in field research vary across branches of science, disciplines. ...

at the sinkhole in the summer of 2004, but there was about one weeklong dig a year from 2005 to 2011.Grant Troutman, "Ancient Bones Still Thrill," ''The News-Sentinel'' (Fort Wayne, Indiana), July 1, 2011, 1A, col. 1.
/ref> What probably was the last work at the site took place in 2014, with scientists and volunteers screening soil previously removed from the sinkhole.

References

* Farlow, James O. and Anne Argast, ''Preservation of Fossil Bone from the Pipe Creek Sinkhole (Late Neogene, Grant County, Indiana U.S.A.)'', Journal of the Paleontological Society of Korea, 22(1):51-75, 2006. * Farlow, James O. et al., ''New Vertebrate Fossils from the Pipe Creek Sinkhole (Late Hemphillian, Grant County, Indiana)'' Paper No. 7-1, delivered at Geological Society of America, North-Central Section - 38th Annual Meeting (April 1–2, 2004), St. Louis, Missouri. * Farlow, James O. et al., ''The Pipe Creek Sinkhole Biota, a Diverse Late Tertiary Continental Fossil Assemblage from Grant County, Indiana''. American Midland Naturalist, 145:367-378. * Kash, Steve, ''Amazing Fossils: Grant County Discovery Reveals Life from 3-6 million years ago'', Outdoor Indiana, March/April 1999. * Kash, Steve, ''Dr. Jack Sunderman Looks at Ancient River'', Outdoor Indiana, November/December 2001. * Martin, Robert A., H. Thomas Goodwin and James O. Farlow, ''Late Neogene (Late Hemphillian) Rodents from the Pipe Creek Sinkhole, Grant County, Indiana''. Journal of Vertebrate Paleontology 22(1):137-151, March 2002. * Sheets, Hope A., and James O. Farlow, ''Size-Frequency Distribution of Leopard Frogs (rana pipiens complex) from the Late Tertiary Pipe Creek Sinkhole, Grant County, Indiana'', Paper no. 16-11 presented at the 37th Annual Meeting of the North-Central Section, Geological Society of America, 24–25 March 2003, Kansas City, Missouri. * Simo, J.A., and Patrick J. Lehmann, ''Diagenetic History of Pipe Creek Jr. Reef, Silurian, North Central Indiana, U.S.A.'', Journal of Sedimentary Research, 70(4):937, July 2000. * Sunderman, Jack A., ''Surprises in a Sinkhole'', ACRES Quarterly, 42(3), Autumn 2003, published by ACRES Land Trust, Fort Wayne, Indiana.

External links

The Pipe Creek Sinkhole

Hillsdale College: Pipe Creek Sinkhole Project

Hillsdale College: Animals of the Pipe Creek Sinkhole

The Paleobiology Database: Taxonomic list for Pipe Creek Jr. Reef, Pipe Creek Jr. quarry, Grant County, Indiana: Silurian, Indiana
*
Large-scale topographic map from TopoQuest

Bing Maps: The Pipe Creek Sinkhole
*Farlow, James O. et al. (eds.)
''Geology of the Late Neogene Pipe Creek Sinkhole (Grant County, Indiana)''
Indiana Geological Survey Special Report 69, January 2010. Retrieved 21 October 2014. *

{{Coord, 40.46081, -85.79462, type:city_region:US, format=dms, display=title Sinkholes of the United States Landforms of Grant County, Indiana Quaternary Indiana Pliocene United States Pliocene paleontological sites of North America Geologic formations of Indiana Paleontology in Indiana 1996 in paleontology

Origin and importance

The sinkhole's ecology

See also

References

External links