Monday, September 2, 2019

Mammoth Cave National Park, Kentucky

This is our second trip to Mammoth Cave National Park, so we did not take any of the tours. On our last trip in 2011 we took the Historic Tour, but I have no pictures from that tour. The pictures here are just from the Visitor Center, which has a wonderful display and explanation of the cave system. Mammoth Cave is the most extensive cave system on Earth. It took about 4,000 years of water intrusion for the cave to form, carved out of sandstone and shale. Over 365 miles have been surveyed and Geologists think there could be 600 miles of undiscovered passageways. It is over twice as long as any known cave.

The passageways of Mammoth Cave cover hundreds of miles. They don't stretch in a straight line, but intersect and run above and below each other like a big but shallow plate of spaghetti. The cave system holds one of the world's most diverse cave ecosystems. About 130 forms of life can be found in Mammoth Cave. Most are quite small. Some use the cave only as a haven, while others are such specialized cave dwellers that they can live nowhere else. 

150 miles of passages

For generations guides have led tours at Mammoth Cave. For many years the guide house was their base of operations. 

Guide Stephen Bishop

Stephen Bishop was a self-educated enslaved man who became a legendary cave guide and explorer. He began guiding visitors at age 17 in 1838. He was the first person to explore many miles of the vast cave. Bishop discovered many miles of cave. He was first to cross the previously impassable Bottomless Pit and the first to see the cave stream's natural residents, called eyeless cavefish.

Gravestone of Stephen Bishop

European American settlers came to the Green River valley in the late 1790s. Like native people before them, the newcomers found uses for Mammoth Cave. The cave served as a mine for saltpeter, key to the manufacture of gunpowder. Before the War of 1812 enslaved workers mined large quantities of this mineral.

By war's end Mammoth Cave's notoriety had grown. Around 1816 people started to visit the cave. In 1838 Stephen Bishop and Mat and Nick Bransford, enslaved persons owned and leased by the cave's owners, became renowned guides. The Bransfords and their descendants were guides at Mammoth Cave for over 100 years.

Civil Engineer, Max Kamper

Guide Ed Bishop

Max Kamper, a German civil engineer, was hired by the cave's manager to survey the cave in 1908. He worked with guide Ed Bishop, Stephen Bishop's grand-nephew, to create a map that shows the relationship of cave passages.

Floyd Collins

Amateur caver Floyd Collins drew national media attention in 1925, pinned for days by a boulder in Sand Cave. He died before rescuers could free him. The publicity played a role in Mammoth Cave being made a national park in 1926.

Frances Benjamin Johnston (1864-1952)

In 1891 an enlightened woman entered Mammoth Cave with a camera, a lantern, and a potentially explosive mixture of pyrotechnic powders mixed in twists of newspaper, which she strategically distributed, when lit, prior to snapping the shutter. Other photographers were just beginning to have success using this "flash light" method to expose a dark scene. Some were maimed or killed using it. She embraced the challenge. 

When Ms. Johnston began her career as a magazine illustrator she did not set out to be a pioneering photojournalist, but her path veered when she began experimenting with the newly invented Kodak camera. Enamored with this emerging art form, Frances quickly gain repute as a successful photographer who complemented her photos with well-written, insightful articles.

"Mammoth Cave by Flash Light" was one such success. Chronicling the frustrations and hazards she experienced with her camera underground, this magazine article was beautifully illustrated with numerous photos of now famous subterranean scenes. Her work capturing the cave's darkness and mystery was pronounced "the finest series of underground pictures yet produced. They represent the most successful and elaborate effort ever to illustrate the Mammoth Cave."

True to her character, Frances enjoyed a Bohemian lifestyle while never transgressing the boundaries of a proper Victorian lady. She expressed this same edginess, tempered with realism and integrity for the subject, in her art.

A landscape in which water moves rapidly underground by dissolving rock is called a karst landscape. Limestone is a common soluble rock, and karst landscapes are found throughout the United States and the world. Mammoth Cave's karst landscape is part of one of this nation's largest regions of cavernous rocks. Caves and springs commonly occur in karst regions like Kentucky, southern Missouri and Florida. 

The word "karst" comes from Slovenia's Kras region, which has a tradition of studying and preserving caves and groundwater resources. Mammoth Cave's partnership with several Slovenian cave organizations is enhanced through this shared tradition.

South China Karst World Heritage Site

Shilin Stone Forest National Park, part of the South China Karst World Heritage Site, is known for its aboveground limestone "forests." Chinese park managers share challenges of protecting against groundwater contamination and development pressures. This World Heritage Site is Mammoth Cave National Park's first sister park.

Postpjina Cave, Slovenia

Karst is key to Mammoth Cave's origin because rock must be readily dissolved by mildly acidic water for cave passageways to form. What Mammoth Cave has that some other karst caves lack is an insoluble sandstone roof. Sandstone protects the rocks below it.

The Big Room at Carlsbad Caverns National Park in New Mexico is one of the best-known karst features in the United States. In the last 600 million years, shallow seas repeatedly came and went over what is now the United States. Limestone in central and southern North America's karst areas formed in these areas.

Sinkholes can make sudden, unwelcome appearances, like this pit in Florida in the 1970s.

How was Mammoth Cave formed? Limestone caves like Mammoth Cave are formed by the water acting on rock over a very long time. South-central Kentucky perfectly combines these factors to form long cave systems. As rain and snow fall on the Sinkhole Plain south and east of the park, the underground journey begins. Raindrops pick up carbon dioxide as they fall through the air and work their way through the soil. Now the water is slightly acidic ~ just enough to slowly dissolve the rock as it seeps through cracks in layers beneath the soil. Over thousands of years, cracks grow big enough for a person to crawl through. Over millions of years, narrow crawlways became huge passageways. Water finds its way into the limestone layers beneath our feet through sinkholes and sinking creeks. Rock layers are angled just enough to make water flow as underground streams and emerge as springs along the Green River.

Water rushes, seeps, trickles and drips into the cave from the Sinkhole Plain. It flows in both streams and as water droplets that slowly work through the soil. Carbonic acid, the same acid found in soft drinks, dissolves rock and carves cave passages. Ponds in the Sinkhole Plain quickly drain underground. The water eventually flows through caves.

On the Sinkhole Plain, rain and melting snow quickly find ways underground through thousands of openings called sinkholes. Some sinkholes formed when cave passageways collapsed. They can be several hundred feet in diameter and more than 100 feet deep. Other sinkholes form as limestone is dissolved when water flows through openings not much wider than pipes in your house. So many sinkholes exist in the Mammoth Cave area that water quickly disappears underground. That's why so few surface streams and creeks exist on the Sinkhole Plain.

Our Dynamic Planet

Earth has changed continually throughout geologic time. Slow moving tectonic plates of Earth's crust control the positions of continents and their geography and climate. Shifting continents profoundly affect climate patterns over time, and climate influences rock deposits. When the rocks Mammoth Cave later formed in were deposited more than 330 million years ago, what is now Kentucky lay in the tropics. This map shows North America 330 million years ago.

Only one major landmass existed 330 million years ago. Geologists called it Pangea, which means "all earth." A shallow sea lay at the super-continent's west edge and covered most of future North America. All the rock within Mammoth Cave is limestone, deposited layer by layer, in this ancient sea over tens of millions of years.

The cave's limestone formed in a world we wouldn't recognize today. There was very little dry land. The air was warm and humid all the time. Very few of the plants and animals we know today had evolved. Coral reefs, colorful fish, and sharks lived in the shallow tropical sea that covered what is now North America. The ocean teemed with invertebrates that had body parts formed of calcium. When these animals died, their remains drifted to the ocean floor. The cave's limestone formed from the sea floor's ooze - calcium carbonate from shells of corals, shellfish and microscopic sea life.

The shallow sea that covered much of North America started to dry up 310 million years ago. Rivers moving through sand at the margins of ancient oceans formed the sandstone deposits that cap the limestone layers. This sandstone roof protects the softer limestone beneath. Africa and North America collided, causing uplift of the Appalachian Mountains. The seas over what is now the central United States dried up, and much of the sedimentary rock that formed in this area later eroded away.

Millions of years (MYA) ago the shallow seas receded from this region as continental plates continued to shift. This new, dry environment was inhabited by countless species for millions of years.  As these plants and animals died, their remains became a part of landscape. Why is the life from these hundreds of millions of years missing from the geologic record? Most of the evidence was physically eroded away by wind and rain. Around 15 MYA, water traveling to the Green River began cutting into the now exposed Mississippian limestone, eventually creating what would become a world renowned cave system.

Scale Tree Trunk Fossil

Crinoid fossil

This crinoid, a relative of the starfish, lived in ancient seas 330 million years ago. Crinoid fossils are found in limestone around the world.

Logsdon River

River Styx

Several underground rivers run through the Mammoth Cave system, including Logsdon River. The River Styx flow underground through the cave and emerges near the Visitor Center, carrying water to the Green River. When the river floods, water backs up into the cave, carrying nutrients vital to life inside the cave. The bottom picture is drops of water on cave limestone.

Cleaveland Avenue, which is tube-shaped, formed as water flowed slowly at the water table.  Often such tubes are completely filled with water as they form.

A shaft forms as dripping water dissolves a vertical passage through layers of limestone then exists at a drain at the bottom.

Fat Man's Misery is a key-hole shaped passage. The tube at the top formed at the water table. Later the water table fell, and the canyon formed as the water cut down to its new level.

Cave drapery occurs is areas where the protective sandstone caprock has eroded away or broken down.

Gypsum Flower

Mammoth Cave's dry passages are an ideal environment for the formation of gypsum flowers. When small amounts of water bearing calcium and sulfur percolate through the rock and then evaporate, these delicate formations take shape. 

Cave Cricket

The cave cricket is one of the most important members of the cave community. Ecologists call it a keystone species. Because cave crickets return to the cave after feeding on the surface, they bring much needed nutrients into the cave environment. The guano and eggs they deposit in the cave support invertebrate communities, including beetles, springtails, pseudoscorpions, and bristletails.

Eyeless Cavefish

Eyeless cavefish live in dark streams underground and have no need for eyes or coloration. They feed on cave invertebrates (and sometimes each other) but can live for up to two years without food.

Cave Salamander

Thirteen species of bats can be found in Mammoth Cave National Park. Nine of these species live in caves at least part of the year. While thousands of bats live in the cave, they are seldom seen because they frequent more remote sections of the cave. They were once more abundant in the cave, but saltpeter production and other activities disturbed their colonies and changed the cave environment. Today their cave roosts are protected by bat gates that keep people away but let fly in and out.

Cave Shrimp

Cave shrimp are sightless, but well adapted to their dark environment. Found only in the Mammoth Cave area, these rare crustaceans live in the very lowest levels of the cave. It is difficult to study them, and we still have much to discover about their lives in the dark.

Northern Cavefish

The Northern cavefish is distantly related to trout and perch. It is the larger of the two that live in the park. It grows to about five inches long and can live up to 60 years and go two years without eating if necessary. Charles Darwin was fascinated by northern cavefish. "It is well known," he wrote, "that several animals which inhabit the caves of Kentucky are blind." Darwin theorized that the fish lost the ability to see because it would not use its eyes in the cave's eternal darkness. 

Amphipods like this one eat the thin film of microscopic life on the surfaces of the rocks and organic matter washed into the cave. They apparently rely upon evasive action to avoid becoming a snack for crayfish.

Cave Crayfish

The eyeless cave crayfish grows to more than four inches long. It has no pigmentation in its outer shell. Its claws make a formidable predator of small invertebrates in pools and streams.

Over 10,000 years ago Paleo-Indians hunted animals in the Green River valley near Mammoth Cave. From 4,000 to 2,000 years ago, Late Archaic and Early Woodland Indians explored and mined minerals from Mammoth and other caves. Artifacts these earliest explorers left, including cane reed torches they used to light their way into distant parts of the cave, are preserved in drier passageways. Made from bundles of river cane or false foxglove, the Indian cavers apparently carried enough torch material for extended explorations.

Mammoth Cave's Indian peoples were daring and accomplished cavers. Carrying river cane torches, they explored the cave, bringing back minerals and crystals and leaving behind broken sandals, burnt-out cane torches, and traces of their food plants: goosefoot, sumpweed, sunflower and maygrass.

Carbon dating shows that Indians ventured into the cave from before 5,000 to about 2,200 years ago. Evidence of later use has not been found. Why? We don't know. No written records or stories are known that could solve one of Mammoth Cave's great mysteries.

Cane torches

Before Mammoth Cave belonged to the American people as a national park and to the plant as a World Heritage site, this was a homeland. First and for nearly 10,000 years, American Indians gathered food, grew crops and hunted in the area. They lived under rock shelters and in villages near the river. After disease, war and broken treaties pushed the Indians from the land, a new community arose. Descended from the Scotch-Irish, French, Germans, and enslaved Africans, the settlers cleared forests, built homes and planted crops. Like the clay on riverbanks or the deer in the woods, the cave is part of the land that sustains the human body and spirit.

Saltpeter production

One of the earliest uses for Mammoth Cave was as a source of nitrate for producing saltpeter, a key ingredient in gun powder. In the first decade of the 1800s commercial production of saltpeter began, and enslaved African Americans were brought to the cave to produce nitrates from cave sediments. 
Families living in the area ....

Robert Montgomery Bird, Gatewood's House, 1837

The long dresses and snug blouses of everyday clothing in the 1800s and early 1900s made touring the cave difficult for women. Not wanting to miss the wonders of the cave, women wore bloomers or "Turkish dresses" that let them move freely yet still be dressed modestly.

Woolsey Family, 1895

One-room School House

Cave guide Will Garvin
Mammoth Cave Baptist Church

CCC Workers
Carolina Parakeet

Many factors led to the extinction of the only parrot native to the Southeast. It lost much native habitat when forests were cleared for agriculture. Many were shot as pests when they raided cornfields and orchards. The last Carolina Parakeet died in a zoo in 1918.

Passenger Pigeon

Once perhaps the most abundant bird on the planet, flocks numbering in the billions darkened the skies for hours during their migrations in springt and fall. Their huge roosts and nesting colonies provided easy access for hunters.

Mammoth Cave National Park is also a World Heritage Site and Biosphere Reserve. The park was named a World Heritage Site in 1981 and became the core area of an International Biosphere Reserve in 1990. With its 53,000 surface acres and underlying cave ecosystem, Mammoth Cave is an international treasure. 

And of course, we had an encounter with a wild animal. As we walked across the bridge we saw the creature munching on grass, and when we came back it was lying down. Jim got out his iHunt animal noises and it responded by looking up at us:

Quote for the day: "The whole country is a bed of limestone, with as many caverns below as there are hills above ...." ~~ The American Monthly Magazine, 1837

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