For 100 years, the National Park Service has preserved America’s special places “for the enjoyment, education, and inspiration of this and future generations.” Celebrate its second century with the Find Your Park GeoTour that launched April 2016 and explore these geocaches placed for you by National Park Service Rangers and their partners.
geocaching.com/play/geotours/findyourpark
History
Russell Cave National Monument was established in the early 1960's when 310 acres donated to the American people were set aside to protect the site and its surroundings.
Some of the artifacts found in the cave are displayed at the visitors center and museum. On request and depending on park staff availability, interpreters give demonstrations on weapons and tools from the Archaic period and on food preperation and cooking methods.
The rock out which Russell Cave was carved was formed more than 300 million years ago at the bottom of the inland sea then covering the region. A layer of carbonaceous deposits (skeletons and shells) was transformed into limestone by the pressure of overlying water, sand, and mud. After the sea retreated, water dripped through fissures in the limestone. The drips became rivulets and then underground streams that cut thousands of tunnels and caverns. About 9,000 to 11,000 years ago, the collapse of a cavern roof beneath a hillside in Doran Cove created a sinkhole and exposed a tunnel carrying water deeper beneath the ground --- Russell Cave. Part of the tunnel entrance was raised above water level by continuing rock falls, and it was here that humans sought shelter as early as 7,000 B.C. It grew higher with silt deposited by flooding of the creek that still drains into the cave. The combined processes - deposits and ceiling rock falls-caused the cave mouth to migrate up the hillside. Although the deposits eventually raised the floor above flood level, human debris and a steady rain of fine material from the roof raised it another 7 or 8 feet. Today the floor of the upper entrance is some 30 feet above the original rock fall.
General Sinkhole
A sinkhole, also known as a sink, shake hole, swallow hole, swallet, doline or cenote, is a natural depression or hole in the surface topography caused by the removal of soil or bedrock, often both, by water. Sinkholes may vary in size from less than a meter to several hundred meters both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms. They may be formed gradually or suddenly, and are found worldwide.
Mechanisms of formation may include the gradual removal of slightly soluble bedrock (such as limestone) by percolating water, the collapse of a cave roof, or a lowering of the water table. Occasionally a sinkhole may exhibit a visible opening into a cave below. In the case of exceptionally large sinkholes, such as Cedar Sink at Mammoth Cave National Park, USA, a stream or river may be visible across its bottom flowing from one side to the other.
Sinkholes may capture surface drainage for running or standing water, but may also form in currently high and dry locations. The state of Florida in the USA is known for having frequent sinkholes, especially in the central part of the state. The Murge area in southern Italy also has numerous sinkholes. Sinkholes can be formed in retention ponds from large amounts of rain.
A special type of sinkhole - formed by rainwater leaking through the pavement and carrying dirt into a ruptured sewer pipe. Sinkholes near the Dead Sea, formed by dissolution of underground salt by incoming freshwater, as a result of a continuing sea level drop.Sinkholes are usually but not always linked with karst landscapes. In such regions, there may be hundreds or even thousands of sinkholes in a small area so that the surface as seen from the air looks pock-marked, and there are no surface streams because all drainage occurs sub-surface.
Sinkholes have been used for centuries as disposal sites for various forms of waste. A consequence of this is the pollution of groundwater resources, with serious health implications in such areas.
Sinkholes also form from human activity, such as the rare but still occasional collapse of abandoned mines in places like West Virginia, USA. More commonly, sinkholes occur in urban areas due to water main breaks or sewer collapses when old pipes give way. They can also occur from the overpumping and extraction of groundwater and subsurface fluids.
Requirements
Q1 - What causes sink holes? (in the text)
Q2 - Approx. how long ago was the sink hole created?
Q3 - The Russell Cave Point was found near the sink hole in early excavations, during what time period was the Russell Cave Point created and/or used?
Q4 - Approx. how wide is the sink hole and How deep is it?
P1 - Take a picture in front of the sink hole, like the sample picture.