Pipe Creek Sinkhole

Pipe Creek Sinkhole near Swayzee in Grant County, Indiana, is one of the most important paleontological sites in the interior of the eastern half of North America. Uncovered in 1996 by workers at the Pipe Creek Junior limestone quarry, the sinkhole has yielded a diverse array of fossils from the Pliocene epoch dating back five million years. Discoveries have been made there of the remains of camelids, bears, beavers, frogs, snakes, turtles and several previously unknown species of rodents. Two fish taxa, bullhead ("Ameiurus") and sunfish ("Centrarchidae"), have also been found there.

Origin and importance

Pipe Creek Sinkhole preserves an ancient wetland. It was created by the collapse of a limestone cave in a Silurian reef formation. That left a steep-sided depression about 75 meters long, 50 meters wide and 11 meters deep. When water collected in the depression, it became the habitat of the plants and animals whose remains were preserved there when the sinkhole was buried by glacial outwash and till during the Pleistocene Epoch, two million to 11,000 years ago.

While the ecology of the Pliocene in North America is well-known from fossil discoveries in other places, notably coastal sites, the Pleistocene glaciers destroyed or scattered most of the fossil remains in the continent's interior. 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 that included both extinct and extant forms. The climate was warm and temperate, but somewhat dry, possibly supporting a grassland-forest transitional zone. The preserved vertebrate fauna are dominated by aquatic species, particularly leopard frogs, which are still common throughout the United States. Mammalian finds include an early rhinoceros ("Teleoceras", possibly from the Miocene epoch), canids, peccaries and short-faced bear.

Backed by a grant from the National Science Foundation, researchers from the Indiana State Museum and several universities substantially completed field work at the sinkhole in the summer of 2004, but the job of describing the fossils and determining their significance will take many years.

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.

ee also

*Ashfall Fossil Beds
*Gray Fossil Site
* List of fossil sites "(with link directory)"

External links

* [http://www.angelfire.com/in4/earthpages/pipe_creek.html Pipe Creek Sinkhole]
* [http://www.hillsdale.edu/academics/fac7294423.asp Hillsdale College: Pipe Creek Sinkhole Home Page]
* [http://paleodb.org/cgi-bin/bridge.pl?action=displayCollectionDetails&collection_no=6706 The Paleobiology Database: Taxonomic list for Pipe Creek Jr. Reef, Pipe Creek Jr. quarry, Grant County, Indiana: Silurian, Indiana]

** [http://www.topoquest.com/map.asp?lat=40.46081&lon=-85.79462&datum=nad83&u=4&layer=DRG100&size=l&s=50 Large-scale topographic map from TopoQuest]