Pipe Creek Sinkhole
Pipe Creek Sinkhole is near the small towns of Swayzee and Converse in Grant County, Indiana. This sinkhole is one of the most important paleontological sites in the interior of the eastern half of North America. This sinkhole is important as it was inadvertently preserved because it was buried by glacial till. Uncovered by excavation workers at the Pipe Creek Junior limestone quarry, the sinkhole has yielded a diverse array of fossils from the Pliocene epoch dating back millions of 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.
In 1986, Richard Huffman, an employee of Irving Materials Incorporated, was clearing soil from the sinkhole in the Pipe Creek Jr. stone quarry. He spotted a bone in the dirt of his backhoe and called in other workers to take a look. What Huffman had uncovered ended up being one of the most important fossil finds east of the Mississippi River. The animal and plant remains found in the Pipe Creek Jr. sinkhole predated the Ice Age and had been a missing chapter in Indiana history.
IMI stopped their limestone mining operations in that area of the quarry in 1987. Paleontologists from Indiana Purdue Fort Wayne and the Indiana State Museum were called in to assess the site. In the summer of 1988, they began to excavate the sinkhole at the IMI site. Thousands of bones were discovered, including giant tortoises, camels as large as giraffes, bears, dogs, peccaries, and big cats. One of the more rare finds was that of a teleoceras, or water rhinoceros. The fossils supplied evidence to just how different the landscape of Indiana was in the past. Finding the remains of animals that are indigenous to much warmer and arid environments suggested strongly that Indiana did not freeze during this time period.
Dr. James Farlow, Professor of Geology from IUPUI, and Ron Richards, Chief Curator of Natural History, Curator of Paleobiology for the Indiana State Museum have spearheaded the excavation at the Pipe Creek Jr. site ever since. Backed by a grant from the National Science Foundation, researchers from the Indiana State Museum and many other universities have completed field work at the sinkhole since 2004. What probably was the last work at the site took place in 2014, with scientists and volunteers screening soil previously removed from the sinkhole. Outside of helping to move debris for the excavation workers, IMI has left the sinkhole area alone since its discovery. IMI has donated the majority of the fossil find to the Indiana State Museum.
The 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, 2 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 ancient wetland was home to a large and dense plant and animal population that includes 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 Miocene epoch), canids, peccaries and short-faced bear.
The book detailing the historical significance of this sinkhole is below
Please answer the following questions correctly in order to be able to claim the smiley for this earthcache. I expect the required logging information for this earthcache to be sent to me within three days of posting a "Found It" log or posted logs will be deleted. Thanks!
1. From the reference point, looking south at the exposed earthcache hillside, how many layers of sediment can you see? They will be marked by differing layers of stone and/or colors.
2. The two specific fish fossils that were found at this sinkhole came from the third layer of sediment; what color is this sediment?
3. Considering the surrounding environment, why do you think the third layer of sediment is unique in its color?
4. Including this sinkhole, how many Pliocene age ecologic examples are located in the central part of the eastern United States?
5. Please post a picture of yourself with GPSr at the sinkhole overlook/reference point (not required but highly encouraged!).
Do not post answers online but rather send the required answers in a separate E-Mail.