Speleology

Errrrr..... and the question is?

Carbonic acid is a solution of carbon-dioxide in water. It can dissolve limestone (calcium carbonate), dolomite (magnesium carbonate) and gypsum (calciumm sulphate).

+++ This was flagged on "gibberish" grounds. The question is badly worded but but after gently teasing the writer about that, I answered seriously & concisely what I took to be his or her enquiry.

Groundwater creates caves through a process called chemical weathering, which dissolves rock over time. As water seeps through the ground, it reacts with minerals in the rock, slowly eroding it and creating cavities. Over thousands of years, these cavities can grow larger and eventually form caves.

When a cave erodes all the way through, it creates a natural tunnel or passage known as an arch or natural bridge. This process typically occurs when water erodes the rock formations over time. These geological features are often found in areas with limestone or other soluble rock formations.

It has no directrole. Caves are formed in limestone primarily by slightly acid ground-water dissolving it. The acidity comes from the water falling as rain, absorbing carbon dioxide from the atmosphere. The result is the weak carbonic acid - natural soda-water in fact!

If bacteria have any role at all it may be forming acids in the soil by decay of organic matter, to augment the carbonic acid, but this is aminor part.

So essentially, bacteria play no part in cave development.

Rime is a type of ice. It is water droplets that become suspended in clouds when temperatures are below freezing. When the move out of the cloud, the droplets freeze quickly when they contact anything solid (i.e., a mountain, plant, or building). The freezing droplets coat the object with what appears to be snow or ice, but is it actually much more delicate. Rime poses a significant problem to climbers in areas such as Patagonia, particularly near Cerro Torre, where climbers are often forced to explore knew routes to avoid climbing on the delicate rime. Because Cerro Torre, and to a lesser extent Fitz Roy, are shrouded in clouds quite frequently, rime frequently forms on the rock and on Cerro Torre's mushroom cap. (Posted by Mark Williams)

Abiotic factors found in caves include temperature, humidity, air circulation, and light availability. These factors play a crucial role in shaping the cave environment and influencing the types of organisms that can survive within them.

To a large extent, rock is already frozen. There are 5 states of matter: * Plasma * Gas * Liquid * Liquid Crytal * Solid Liquid crystal only applies to certain highly specialised compounds, although there is some evidence that all of them experience this stage in a very narrow band between solid and liquid, but that this band is so narrow that it's almost impossible to attain without it going beyond. Plasma is a gas so highly heated that all molecules break down and the electrons disasociate - they are no longer bound to their atoms. This leaves Solid, Liquid and Gas. If you view the following image: http://www.geocities.com/paul_j_hurley@btinternet.com/education_items/images/ water_states.jpg edit: it keeps on doing this! the above should all be 1 line! This is a diagram of the normal states of matter for water. If you cross reference the temperature with the pressure, you will get the relevant state. I've drawn a blue ine on the diagram for a pressure of 1 atmosphere. as you go up this line (rising temperature) then at 0 degrees centigrade you move from the solid area to the liquid area and at 100 degrees into the gas area. This also explains why at lower pressures (such as up a mountain) water boils at a lower temperature (move the blue line to the left). Where the 2 red lines meet is called the triple point. If you now view the following diagram: http://www.geocities.com/paul_j_hurley@btinternet.com/education_items/images/ 2-state.jpg Edit: and again. I've put water (red line) and another compound (green line) on the same diagram You will note they are both the same shape, but the triple points are in vastly different places, according to the chemical properties of these compounds. So, for a temperature and pressure at the blue cross, water is a liquid and the other substance (such as rock) is a solid. I.e. rock is already a frozen solid at this temperature. You will also note that to the left of the triple point, it goes straight from a solid to a gas. This is called sublimation. Depending on where the triple point of the substance is, all compounds sublime below this. Water will sublime below approximately 0.006 atmospheres (it's triple point is at this pressure), wheras carbon dioxide has it's triple point at 5.2 atmospheres. This why carbon dioxide 'dry ice' has no liquid form (the pressure ON EARTH is too low), while on Mars, with an atmospheric pressure of 0.005 atmospheres, liquid water cannot form (although it can form both a gas and a solid - believe it or not it can snow on mars, but not rain.)

Maple, birch, cedar.

Water is considered a renewable resource because it is naturally replenished through the water cycle, which involves evaporation, condensation, and precipitation. Oil, on the other hand, is a non-renewable resource because it is formed from organic matter over millions of years and cannot be replenished at the rate it is consumed.

The Krubera Cave, also known as Voronya Cave, is the deepest cave system on Earth, located in the Arabika Massif of the Western Caucasus in Abkhazia, Georgia. It reaches a depth of 2,197 meters (7,208 feet).

Dissolution of the limestone by rain & snow-melt water slightly acidified by absorbed atmospheric carbon dioxide. It oozes through the rock's joints, bedding-planes & other discontinuities from surface to rising (spring). Eventually these initial micro-conduits start to coalescence and develop discrete passages.

Speleology is the scientific study of caves, including their physical structure, formation, geological characteristics, and biological contents. Speleologists explore caves to understand their environment, history, and the processes that shape them. They may study cave formations, underground water systems, and the unique ecosystems that exist within caves.

A volcanologist studies volcanoes, including their activity, behavior, and impact on the environment. Volcanologists may study various aspects of volcanoes, such as eruptions, magma composition, and volcanic gases, to better understand and mitigate volcanic hazards.

Cave passages can be humid due to water seepage from the surrounding rock layers or the presence of underground streams and rivers. The lack of ventilation in caves also contributes to high humidity levels by trapping moisture in the air.

Some people un-familiar with caves or possibly a person advertising a cave will claim a pit is "bottomless." Usually you can't see the bottom of these pits, so their story is convincing. Also, they may throw a rock into the pit, it lands in soft dirt and doesn't make a sound, so some gullible people will believe them. The answer to the question is that most of these pits are not even a 30 meters deep. A person should not enter these pits without proper training on techniques for climbing long free-hanging ropes. There are thousands of caves where the pit could be 100 meter free-fall. and there are plenty more deeper than that. The Velebita Pit in Croatia is the deepest pit inside of a cave at 513 meters deep. You would be far safer rappelling off of a sky-scraper, than exploring a deep pit without training or the proper equipment.

A shawl is a calcite formation and forms when water runs down a gentle slope rather than falling straight to the floor.

See the link below for a good picture taken in the Jenolan caves near Sydney, Australia.

A karst specialist is a geologist who is expertized in Karst Geomorphology. This type of scientists study the conditions and the procedures that lead to the formation of karst in limestone rocks.

Glacio-speleology is the study of caves within glaciers. It involves exploration and research focused on understanding the formation, structure, and dynamics of glacier caves, as well as their unique ice formations and processes. This field helps researchers gain insights into glacier behavior and climate change impacts.

Some cave passages may break thru to the surface forming a sky-light. In the zone were the sunlight reaches the soil, trees can live for hundreds of years, growing up all the way out of the cave. Some caves that are large sinkholes have floors that are over an acre in size. It is like a mini-rainforest down deep in those caves.

Artificial light can be used to grow plants in caves. Commercial (or show-) caves sometimes have patches of algae growing near their lamps.*

Seedlings wash deep into caves and sprout, but they usually die off after a few weeks. But this can be a food source to tiny creatures that live in those passages.

+++

*Know collectively as "lampenflora" (German, lit. 'Lamp flora') and now regarded as a nuisance by many show-cave owners. Some show-caves arrange limited lighting, rather than leaving the flood-lights on all the time the cave is open for tours, to minimise such vegetation. The species are generally of ferns and algae introduced as spores on visitor's clothing or wafting in on air-currents.

A subterranean river passage can have water flowing in opposite directions due to complex geological formations and varying water sources. This phenomenon can occur when multiple water sources enter the passage at different points, leading to the flow of water in opposite directions within the underground system. Changes in elevation, pressure, and underground water currents can also contribute to this unique flow pattern.

Sedimentary deposits are thought to exist up to 9 kilometers deep. From 9 kilometers to about 18 kilometers metamorphic layers likely exist. However, temperatures would be very high, along with toxic gases like sulfur. So explorable cave passage at that depth is unlikely. Drill cores in Wyoming have found limestone nearly 26,000 feet deep. Can anyone verify if that Mississipian layer is soluble enough to form explorable caves?

+++

Caves at that depth are not very likely but may form by dissolution by very deep, acidic, geothermal fluids. The normal limit really is not ever so deep below the base level - the altitude of the resurgence for their formative streams. Although they can form deep "sumps" like the U-bend under a sink, the limestone formation's own depth sets the limit, whatever the rock below it. So although sedimentary rock may be 9km deep, the cavernous limestone is likely to be far less.

Also, it's not the solubility of the limestone that's the problem. It's the physical nature of the formation, the relationship to basement and cover rocks, and hydrology of its region that matter.

Caves do not form naturally in slate with the possible exception of sea-caves (and then would be inherently unstable) and shallow rock-shelters.

Slate mines (entirely artificial) can be very extensive but these are man-made.

Most of the world's caves are Karst features, i.e. primarily in Limestone. Karst caves need three materials: a soluble rock like Limestone or Gypsum, water and Carbon-dioxide (CO2). The last two combine to form a weak acid that dissolves the limestone. For a fuller account: The host limestone needs to be of appropriate physical structure and raised into hills, then subjected to reasonably consistent precipitation for many tens or hundreds of thousands of years. Limestone is a sedimentary rock of which the world's greater proportion was laid down in warm, relatively shallow, seas. The rock was laid in horizontal layers - Beds - separated by Bedding-planes which generally reflect geologically-brief changes in the environment. The suite of beds is known as a Formation, generally named after its "type area". Later continental uplift (tectonic processes) raise the formation along with its underlying rocks, usually tilting and folding it to at least some extent in the process. Since most rocks are brittle they cannot take much stress, and limestone beds crack into grids of fine fractures called Joints. The uplift and folding often also causes Faulting - major breaks with the rock mass one side of the Fault Plane being raised, lowered or moved horizontally past that on the opposite side. (Note: Plane - the "Fault Line" sometimes misused as a political metaphor is that of the fault-plane cutting the land surface.) Now we have the hills, next we need rain-water that has absorbed atmospheric CO2 to create Carbonic Acid (weak, natural soda water in fact!). It may be augmented by acids from the soil, too. This solvent permeates through all those joints, bedding-planes and faults; flowing very, very slowly under considerable pressure applied by its depth, from its sinks on the surface to its springs at the base of the formation. In doing so, it dissolves the limestone (chemical weathering), creating meshes of tiny micro-conduits that over many tens of thousands of years coalesce and capture each other to form cave passages. Once this happens, the rate of erosion can increase - though still to perhaps only a few millimetres per thousand years under generally temperate climates. A cave, or a series within a cave system, that still carries its formative stream is called "Active", and is still being developed. Surface changes such as the valley floor being lowered by erosion, or down-cutting within the cave by its stream, changes the water's route and the original, now dried-out, stream-way is called "Fossil" or "Abandoned". Such passages may be filled with silt left by floods as the main flow gradually abandons them; or may become richly decorated with Speleothems - calcite deposits such as stalactites and stalagmites precipitated from ground-water still oozing through the joints in the limestone above the cave. In time such passages may start to break down as there is no stream to dissolve away slabs falling from the roof as permeating ground-water attacks the rock above. In the end, surface lowering of the landscape as a whole, breaches and destroys the cave. Nothing is permanent in Nature! Caves in limestone are also parts of Karst Landscape. i.e. a landscape developed by the dissolution of limestone, giving surface features like Dolines, Limestone Pavement, and in the tropics, distinctive hills such as those represented in Chinese Willow-pattern images. 'Karst' is from the Slavic word 'Kras', the name for its world type-area. @@@@@ The above is purely an introduction to a vastly more complex and subtle series of processes, of course, and you need to refer to appropriate text-books on geology and cave studies to learn them. The scientific study of caves is Speleology - embracing geology, hydrology, biology, archaeology and other disciplines. Simply visiting caves to enjoy them for their scenery and the physical and mental challenges they present, is called Caving, though you can't study a cave unless you can negotiate its obstacles.

How DO.... and the adjective is superflous since caves are underground by definition! SO to answer:

For the specific geology and development of any individual cave you will have to read the appropriate research papers on that region and its karst features; but if it's a karst cave, as most are, the essentials are:

How Caves Form in Limestone

This is such a common question on 'Answers' I wrote this single reply! The technical terms are introduced by capital initials.

Most of the world's caves are Karst features, i.e. primarily in Limestone.

Karst caves need three materials: a soluble rock like Limestone or Gypsum, water and Carbon-dioxide (CO2). The last two combine to form a weak acid that dissolves the limestone. For a fuller account:

The host limestone needs to be of appropriate physical structure and raised into hills, then subjected to reasonably consistent precipitation for many tens or hundreds of thousands of years.

Limestone is a sedimentary rock of which the world's greater proportion was laid down in warm, relatively shallow, seas. The rock was laid in horizontal layers - Beds - separated by Bedding-planes which generally reflect geologically-brief changes in the environment. The suite of beds is known as a Formation, generally named after its "type area".

Later continental uplift (tectonic processes) raise the formation along with its underlying rocks, usually tilting and folding it to at least some extent in the process. Since most rocks are brittle they cannot take much stress, and limestone beds crack into grids of fine fractures called Joints. The uplift and folding often also causes Faulting - major breaks with the rock mass one side of the Fault Plane being raised, lowered or moved horizontally past that on the opposite side. (Note: Plane - the "Fault Line" sometimes misused as a political metaphor is that of the fault-plane cutting the land surface.)

Now we have the hills, next we need rain-water that has absorbed atmospheric CO2 to create Carbonic Acid (weak, natural soda water in fact!). It may be augmented by acids from the soil, too. This solvent permeates through all those joints, bedding-planes and faults; flowing very, very slowly under considerable pressure applied by its depth, from its sinks on the surface to its springs at the base of the formation. In doing so, it dissolves the limestone (chemical weathering), creating meshes of tiny micro-conduits that over many tens of thousands of years coalesce and capture each other to form cave passages.

Once this happens, the rate of erosion can increase - though still to perhaps only a few millimetres per thousand years under generally temperate climates.

A cave, or a series within a cave system, that still carries its formative stream is called "Active", and is still being developed.

Surface changes such as the valley floor being lowered by erosion, or down-cutting within the cave by its stream, changes the water's route and the original, now dried-out, stream-way is called "Fossil" or "Abandoned". Such passages may be filled with silt left by floods as the main flow gradually abandons them; or may become richly decorated with Speleothems - calcite deposits such as stalactites and stalagmites precipitated from ground-water still oozing through the joints in the limestone above the cave. In time such passages may start to break down as there is no stream to dissolve away slabs falling from the roof as permeating ground-water attacks the rock above.

In the end, surface lowering of the landscape as a whole, breaches and destroys the cave. Nothing is permanent in Nature!

Caves in limestone are also parts of Karst Landscape. i.e. a landscape developed by the dissolution of limestone, giving surface features like Dolines, Limestone Pavement, and in the tropics, distinctive hills such as those represented in Chinese Willow-pattern images. 'Karst' is from the Slavic word 'Kras', the name for its world type-area.

@@@@@

The above is purely an introduction to a vastly more complex and subtle series of processes, of course, and you need to refer to appropriate text-books on geology and cave studies to learn them.

The scientific study of caves is Speleology - embracing geology, hydrology, biology, archaeology and other disciplines.

Simply visiting caves to enjoy them for their scenery and the physical and mental challenges they present, is called Caving, though you can't study a cave unless you can negotiate its obstacles. The enthusiasts are simply Cavers throughout the English-speaking world - you see "spelunkers" sometimes on 'Answers' but it's a 1940s word stuck together from Latin and Greek, and though originally used neutrally by US cavers it started to become derogatory in the 1960s.

The most significant dilution of seawater occurs at the mouths of rivers and streams, where freshwater flowing into the ocean decreases the salinity of the surrounding seawater. Additionally, melting ice caps and glaciers are other sources of dilution in polar regions.