Fall Asleep While Learning About Caves

In this episode of the I Can’t Sleep Podcast, drift off while learning about caves. One of the fascinating aspects of this topic is that some people have discovered caves with such incredible acoustics that they bring in recording equipment and mics to capture songs and spoken content inside. That’s pretty cool! Happy sleeping!

Transcript

Welcome to the I Can't Sleep podcast,

Where I read random articles from across the web to bore you to sleep with my soothing voice.

I'm your host,

Benjamin Boster.

Today's episode is from a Wikipedia article titled,

Cave.

A cave or cavern is a natural void under the earth's surface.

Caves often form by weathering of rock and often extend deep underground.

Exogene caves are smaller openings that extend a relatively short distance underground,

Such as rock shelters.

Caves which extend further underground than the opening is wide are called endogene caves.

Speleology is the science of exploration and study of all aspects of caves and the cave environment.

Visiting or exploring caves for recreation may be called caving,

Potholing,

Or spelunking.

The formation and development of caves is known as speleogenesis.

It can occur over the course of millions of years.

Caves can range widely in size and are formed by various geological processes.

These may involve a combination of chemical processes,

Erosion by water,

Tectonic forces,

Microorganisms,

Pressure,

And atmospheric influences.

Isotopic dating techniques can be applied to cave sediments to determine the timescale of the geological events which formed and shaped present-day caves.

It is estimated that a cave cannot be more than 3,

000 meters vertically beneath the surface due to the pressure of overlying rocks.

This does not,

However,

Impose a maximum depth for a cave,

Which is measured from its highest entrance to its lowest point,

As the amount of rock above the lowest point is dependent on the topography of the landscape above it.

For karst caves,

A maximum depth is determined on the basis of the lower limit of karst-forming processes coinciding with the base of the soluble carbonate rocks.

Most caves are formed and limestoned by dissolution.

Caves can be classified in various other ways as well,

Including a contrast between active and relict.

Active caves have water flowing through them,

Relict caves do not,

Though water may be retained in them.

Types of active caves include inflow caves,

Into which a stream sinks,

Outflow caves,

From which a stream emerges,

And through caves,

Traversed by a stream.

Solutional caves,

Or karst caves,

Are the most frequently occurring caves.

Such caves form in rock that is soluble,

Most occur in limestone,

But they can also form in other rocks including chalk,

Dolomite,

Marble,

Salt,

And gypsum.

Except for salt caves,

Solutional caves result when rock is dissolved by natural acid in groundwater that seeps through bedding planes,

Faults,

Joints,

And comparable features.

Over time cracks enlarge to become caves and cave systems.

The largest and most abundant solutional caves are located in limestone.

Limestone dissolves under the action of rainwater and groundwater charged with H2CO3,

Carbonic acid,

And naturally occurring organic acids.

The dissolution process produces a distinctive landform known as karst,

Characterized by sinkholes and underground drainage.

Limestone caves are often adorned with calcium carbonate formations produced through slow precipitation.

These include flowstones,

Stalactites,

Stalagmites,

Halictites,

Halictites,

Soda straws,

And columns.

These secondary mineral deposits in caves are called speleotherms.

The portions of a solutional cave that are below the water table or the local level of the groundwater will be flooded.

The Chiquilla Cave in New Mexico and nearby Carlsbad Caverns are now believed to be examples of another type of solutional cave.

They were formed by H2S,

Hydrogen sulfide gas,

Rising from below,

Where reservoirs of oil give off sulfurous fumes.

This gas mixes with groundwater and forms H2SO4,

Sulfuric acid.

The acid then dissolves the limestone from below rather than from above by acidic water percolating from the surface.

Caves formed at the same time as the surrounding rock are called primary caves.

Lava tubes are formed through volcanic activity and are the most common primary caves.

As lava flows downhill,

Its surface cools and solidifies.

Hot liquid lava continues to flow under that crust,

And if most of it flows out,

A hollow tube remains.

Such caves can be found in the Canary Islands,

Jejudo,

The Basaltic Plains of eastern Idaho,

And in other places.

Kazamura Cave,

Near Hilo,

Hawaii,

Is a remarkable long and deep lava tube.

It is 65.

6 kilometers long.

Lava caves include but are not limited to lava tubes.

Other caves formed through volcanic activity include rifts,

Lava molds,

Open vertical conduits,

Inflationary blisters,

Among others.

Sea caves are found along coasts around the world.

A special case is littoral caves,

Which are formed by wave action in zones of weakness in seacliffs.

Often these weaknesses are faults,

But they may also be dikes or bedding plane contacts.

Some wave-cut caves are now above sea level because of later uplift.

Elsewhere in places such as Thailand's Phong Nga Bay,

Solutional caves have been flooded by the sea and are now subject to littoral erosion.

Sea caves are generally around 5 to 50 meters in length,

But may exceed 300 meters.

Subtropical or erosional caves are those that form entirely by erosion by flowing streams carrying rocks and other sediments.

These can form in any type of rock,

Including hard rock such as granite.

Generally there must be some zone of weakness to guide the water,

Such as a fault or joint.

A subtype of the erosional cave is the wind or aeolian cave,

Carved by wind-borne sediments.

Many caves formed initially by solutional processes often undergo a subsequent phase of erosional or vadose enlargement,

Where active streams or rivers pass through them.

Glacier caves are formed by melting ice and flowing water within and under glaciers.

The cavities are influenced by the very slow flow of the ice,

Which tends to collapse the caves again.

Glacier caves are sometimes misidentified as ice caves,

Though this latter term is properly reserved for bedrock caves that contain year-round ice formations.

Fracture caves are formed when layers of more soluble minerals,

Such as gypsum,

Dissolve out from between layers of less soluble rock.

These rocks fracture and collapse in blocks of stone.

Talus caves are formed by the openings among large boulders that have fallen down into a random heap,

Often at the bases of cliffs.

These unstable deposits are called talus or scree,

And may be subject to frequent rock falls and landslides.

Anchialine caves are caves,

Usually coastal,

Containing a mixture of freshwater and saline water,

Usually seawater.

They occur in many parts of the world and often contain highly specialized and endemic fauna.

The following are physical patterns of caves.

Branchwork caves resemble surfaced and drittic stream patterns.

They are made up of passages that join downstream as tributaries.

Branchwork caves are the most common of cave patterns and are formed near sinkholes where groundwater recharge occurs.

Each passage or branch is fed by a separate recharge source and converges into other higher-order branches downstream.

Angular network caves form from intersecting fissures of carbonate rock that have had fractures widened by chemical erosion.

These fractures form high,

Narrow,

Straight passages that persist in widespread closed loops.

Anastomotic caves largely resemble surface-braided streams with their passages separating and then meeting further down drainage.

They usually form along one bed or structure and only rarely cross into upper or lower beds.

Spongework caves are formed when solution cavities are joined by mixing of chemically diverse water.

The cavities form a pattern that is three-dimensional and random,

Resembling a sponge.

Cramiform caves form as irregular large rooms,

Galleries,

And passages.

These randomized three-dimensional rooms form from a rising water table that erodes the carbonate rock with hydrogen sulfide enriched water.

Pit caves,

Vertical caves,

Potholes,

Or simply pits,

Consist of a vertical shaft rather than a horizontal cave passage.

They may or may not be associated with one of the above structural patterns.

Caves are found throughout the world,

Although the distribution of documented cave system is heavily skewed towards those countries where caving has been popular for many years,

Such as France,

Italy,

Australia,

The UK,

The United States,

Etc.

As a result,

Explored caves are found widely in Europe,

Asia,

North America,

And Oceania,

But are sparse in South America,

Africa,

And Antarctica.

This is a rough generalization,

As large expanses of North America and Asia contain no documented caves,

Whereas areas such as the Madagascar Dry Deciduous Forests and parts of Brazil contain many documented caves.

As the world's expanses of soluble bedrock are researched by cavers,

The distribution of documented caves is likely to shift.

For example,

China,

Despite containing around half the world's exposed limestone,

More than 1 million square kilometers,

Has relatively few documented caves.

Cave-inhabiting animals are often categorized as troglobites,

Cave-limited species,

Troglophiles,

Species that can live their entire lives in caves,

But also occur in other environments,

Troglozenes,

Species that use caves but cannot complete their life cycle fully in caves,

And accidentals,

Animals not in one of the previous categories.

Some authors use separate terminology for aquatic forms,

For example,

Stagobites,

Stagophiles,

And stagozenes.

Of these animals,

The troglobites are perhaps the most unusual organisms.

Troglobitic species often show a number of characteristics termed troglomorphic,

Associated with their adaptation to subterranean life.

These characteristics may include a loss of pigment,

Often resulting in a pale or white coloration,

A loss of eyes or at least of optical functionality,

An elongation of appendages,

And an enhancement of other senses,

Such as the ability to sense vibrations in water.

Aquatic troglobites,

Or stagobites,

Such as the endangered Alabama cave shrimp,

Live in bodies of water found in caves and get nutrients from detritus washed into their caves and from the feces of bats and other cave inhabitants.

Other aquatic troglobites include cave fish and cave salamanders,

Such as the olm and the Texas blind salamander.

Troglobites,

Such as the gray bat and Mexican free-tailed bat,

Are troglozenes and are often found in caves.

They forage outside of the caves.

Some species of cave crickets are classified as troglozenes because they roost in caves by day and forage above ground at night.

Caves are visited by many surface-living animals,

Including humans.

These are usually relatively short-lived incursions due to the lack of light and sustenance.

Cave entrances often have typical florae.

For instance,

In the eastern temperate United States,

Cave entrances are most frequently and often densely populated by the bulbid fern.

People have made use of caves throughout history.

The earliest human fossils found in caves come from a series of caves near Krugersdorp and Mokopane in South Africa.

In southern Africa,

Early modern humans regularly used sea caves as shelter starting about 180,

000 years ago,

When they learned to exploit the sea for the first time.

The oldest known site is PP13B at Pinnacle Point.

This may have allowed rapid expansion of humans out of Africa and colonization of areas of the world such as Australia by 60,

000 to 50,

000 years ago.

Throughout southern Africa,

Australia,

And Europe,

Early modern humans used caves and rock shelters as sites for rock art,

Such as those at Giant's Castle.

Caves such as the Yaodong in China were used for shelter.

Other caves were used for burials,

Such as rock-cut tombs,

Or as religious sites,

Such as Buddha's Caves.

Among the known sacred caves are China's Cave of a Thousand Buddhas and the Sacred Caves of Crete.

Paleolithic cave paintings have been found throughout the world,

Dating from 64,

800 years old for non-figurative art and 43,

900 years old for figurative art.

The importance of sound in caves predates a modern understanding of acoustics.

Archaeologists have uncovered relationships between paintings of dots and lines in specific areas of residence within the caves of Spain and France,

As well as instruments depicting Paleolithic motifs,

Indicators of musical events and rituals.

Clusters of paintings were often found in areas with notable acoustics,

Sometimes even replicating the sounds of the animals depicted on the walls.

The human voice was also theorized to be used as an echolocation device to navigate darker areas of the caves where torches were less useful.

Dots of red ochre are often found in spaces with the highest resonance,

Where the production of paintings was too difficult.

Acoustics continue to provide usage for modern-day explorers of acoustics.

Today,

Cumberland Caverns provides one of the best examples for modern musical usages of caves.

Not only are the caves utilized for reverberation,

But for the dampening qualities of their abnormal faces as well.

The irregularities in the walls of the Cumberland Caverns diffuse sounds bouncing off the walls and give the space an almost recording-studio-like quality.

During the 20th century,

Musicians began to explore the possibility of using caves as locations as clubs and concert halls,

Including the likes of Dinah Shore,

Roy Acuff,

And Benny Goodman.

Unlike today,

These early performances were typically held in the mouths of the caves,

As the lack of technology made depths of the interior inaccessible with musical equipment.

In Lorry Caverns,

Virginia,

A functioning organ has been developed that generates sound by mallets striking stalactites,

Each with a different pitch.

Caving,

Also known as spelunking in the United States and Canada,

And potholing in the United Kingdom and Ireland,

Is the recreational pastime of exploring wild cave systems,

As distinguished from show caves.

In contrast,

Speleology is the scientific study of caves and the cave environment.

The challenges involved in caving vary according to the cave being visited.

In addition to the total absence of light beyond the entrance,

Negotiating pitches,

Squeezes,

And water hazards can be difficult.

Cave diving is a distinct and more hazardous sub-specialty undertaken by a small minority of technically proficient cavers.

In an area of overlap between recreational pursuit and scientific study,

The most devoted and serious-minded cavers become accomplished at the surveying and mapping of caves and the formal publication of their efforts.

These are usually published freely and publicly,

Especially in the UK and other European countries,

Although in the US they are generally more private.

Although caving is sometimes categorized as an extreme sport,

Cavers do not commonly use this terminology and typically dislike the term being used in reference to caving as it implies a disregard for safety.

Many caving skills overlap with those involved in canyoning and mine and urban exploration.

Caving is often undertaken for the enjoyment of the outdoor activity for physical exercise as well as original exploration,

Similar to mountaineering or diving.

Physical or biological science is also an important goal for some cavers,

While others are engaged in cave photography.

Virgin cave systems comprise some of the last unexplored regions on Earth,

And much effort is put into trying to locate,

Enter,

And survey them.

In well-explored regions,

Such as most developed nations,

The most accessible caves have already been explored,

And gaining access to new caves often requires cave digging or cave diving.

Caving in certain areas has also been utilized as a form of eco and adventure tourism,

For example in New Zealand.

Tour companies have established an industry leading and guiding tours into and through caves.

Depending on the type of cave and the type of tour,

The experience could be adventure-based or ecological-based.

There are tours led through lava tubes by a guided service,

E.

G.

Lava River Cave,

The oceanic islands of Tenerife,

Iceland,

And Hawaii.

Caving has also been described as an individualist team sport by some,

As cavers can often make a trip without direct physical assistance from others,

But will generally go in a group for companionship or to provide emergency help if needed.

Some,

However,

Consider the assistance cavers give each other as a typical team sport activity.

The term potholing refers to the act of exploring potholes,

A word originating in the north of England for predominantly vertical caves.

Clay Perry,

An American caver of the 1940s,

Wrote about a group of men and boys who explored and studied caves throughout New England.

This group referred to themselves as spelunkers,

A term derived from the Latin spelunca,

Cave,

Cavern,

Den.

This is regarded as the first use of the word in the Americas.

Throughout the 1950s,

Spelunking was the general term used for exploring caves in U.

S.

English.

It was used freely,

Without any positive or negative connotations,

Although only rarely outside the U.

S.

In the 1960s,

The terms spelunking and spelunker began to be considered de classe among experienced enthusiasts.

In 1985,

Steve Knutson,

Editor of the National Speleology Society,

N.

S.

S.

Publication,

American Caving Accidents,

Made the following distinction.

Note that in this case the term spelunker denotes someone untrained and unknowledgeable in current exploration techniques,

And caver is for those who are.

This sentiment is exemplified by bumper stickers and t-shirts displayed by some cavers.

Cavers rescue spelunkers.

Nevertheless,

Outside the caving community,

Spelunking and spelunkers predominantly remain neutral terms,

Referring to the practice and practitioners without any respect to skill level.

In the mid-19th century,

John Birkbeck explored potholes in England,

Notably Gaping Gill in 1842 and Alum Pot in 1847-8,

Returning there in the 1870s.

In the mid-1880s,

Herbert E.

Balch began exploring Wookiee hole caves,

And in the 1890s Balch was introduced to the caves of the Mendip Hills.

One of the oldest established caving clubs,

Yorkshire Ramblers Club,

Was founded in 1892.

Caving as a specialized pursuit was pioneered by Edouard Alfred Martel,

Who first achieved the descent and exploration of the Gouffreaux de Paderac in France as early as 1889,

And the first complete descent of a 110-meter wet vertical shaft at Gaping Gill in 1895.

He developed his own techniques based on ropes and metallic ladders.

Martel visited Kentucky and notably Mammoth Cave National Park in October 1912.

In the 1920s,

Famous U.

S.

Caver Floyd Collins made important explorations in the area,

And in the 1930s,

As caving became increasingly popular,

Small exploration teams,

Both in the Alps and in the karstic high plateaus of southwest France,

Transformed cave exploration into both a scientific and recreational activity.

Robert de Jolly,

Guy de Laval,

And Norbert Kastrit were prominent figures of that time,

Surveying mostly caves in southwest France.

During World War II,

An Alpine team composed of Pierre Chevalier,

Fernand Petzl,

Charles Petit-Didier,

And others explored the Dandecral cave system near Grenoble,

Which became the deepest explored system in the world at the time.

The lack of available equipment during the war forced Pierre Chevalier and the rest of the team to develop their own equipment,

Leading to technical innovation.

The Scaling Pole,

1940,

Nylon Ropes,

1942,

Use of Explosives in Caves,

1947,

And Mechanical Rope Ascenders Henri Breneau's Monkeys,

First used by Chevalier and Breneau in a cave in 1934,

Can be directly associated to the exploration of the Dandecral cave system.

In 1941,

American cavers organized themselves into the National Speleology Society,

NSS,

To advance the exploration,

Conservation,

Study,

And understanding of caves in the United States.

American caver Bill Cuttington,

Known as Vertical Bill,

Further developed the Single Rope Technique,

SRT,

In the late 1950s.

In 1958,

Two Swiss alpinists,

Usi and Marti,

Teamed together,

Creating the first rope ascender known as the Umar.

In 1968,

Bruno Dressler asked Ferdinand Petzl,

Who worked as a metals machinist,

To build a rope ascending tool,

Today known as the Petzl Kroll,

That he had developed by adapting the Umar to vertical caving.

Pursuing these developments,

Petzl started in the 1970s a caving equipment manufacturing company named Petzl.

The development of the rappel rack and the evolution of mechanical ascension systems extended the practice and safety of vertical exploration to a wider range of cavers.

Reviews

All I heard was cave, then..zzzzzzzz😂
Thank you as always!! 🤗🤗🤗

Been in a few caves, most memorable in Arkansas as a teenager while visiting family there. We had to crawl through a small space to get in and out. Turned off our flashlights, the darkness was absolute! Decided that was not for me!! Thanks for the reading. Even with my memories it still put me to sleep.

At least this time, I remembered the title! Thank you!