A speleothem (from the Greek for "cave deposit") is a formal term for what is also known as a cave formation, or amongst cavers, collectively known as pretties. They are the result of the interactions among water, rock, and air within caves. sport of exploring caves. ...

Formations in Hall of the Mountain Kings, Ogof Craig a Ffynnon, South Wales

As water seeps through cracks in rock, it dissolves certain compounds; for caves, these compounds are usually calcite and aragonite (both calcium carbonate), or gypsum (calcium sulfate). At first, this water creates passages which grow larger over time, forming a cave. Eventually, these voids within the rock grow large enough that the seeping water contacts air, causing its solutes to precipitate. This precipitation may be a function of concentration through water removal (calcium sulfate, calcium carbonate) or through the loss of carbon dioxide (calcium carbonate). Over tens of thousands of years, these drops cause speleothems to form. Formations may be produced on the ceiling, creating pendulous structures (stalactites) or structures that "grow" from the floor of the cave upwards (stalagmites). Given enough time, stalactites and stalagmites may grow together into a column. Download high resolution version (600x776, 73 KB)The Hall of the Mountain Kings, Ogof Craig a Ffynnon, South Wales. ... Download high resolution version (600x776, 73 KB)The Hall of the Mountain Kings, Ogof Craig a Ffynnon, South Wales. ... Speleothems in Hall of the Mountain Kings Ogof Craig a Ffynnon (Welsh for Rock and Fountain Cave) is a cave of around 13 km in length, making it currently the 6th longest in Wales and 10th in the UK. The cave is renowned as one of the most well-decorated... South Wales is an area of Wales bordered by England and the Bristol Channel to the East and South, and Mid Wales and West Wales to the North and West. ... Calcite from Brushy Creek Mine, Missouri, USA. The mineral calcite is a carbonate of calcium corresponding to the formula CaCO3 and is one of the most widely distributed minerals on the Earths surface. ... Categories: Carbonate minerals | Mineral stubs ... Calcium carbonate is a chemical compound, with chemical formula CaCO3. ... Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. Chemical structure Gypsum from New South Wales, Australia Heating gypsum above approximately 150°C (302°F) partially dehydrates the mineral by driving off exactly 75% of the water contained in its chemical structure. ... Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. Chemical structure Gypsum from New South Wales, Australia Heating gypsum above approximately 150°C (302°F) partially dehydrates the mineral, by driving off exactly 75% of the water contained in its chemical structure. ... Carbon dioxide is an atmospheric gas composed of one carbon and two oxygen atoms. ... Formation of stalactites. ... The Witchs Finger in the Carlsbad Caverns A stalagmite (Greek stalagma, drip) is a type of speleothem formed by the deposit of calcium carbonate which rises from the floor of a limestone cave due to the dripping of mineralized solutions. ...

Various types of formations develop, depending on whether the water drips, seeps, condenses, flows, or settles into pools. Many are named for their resemblance to the man-made or natural objects they resemble. Types of formations include:

• cave pearls, which are the result of water dripping from high above, then causing small "seed" crystals to turn over so often that they form into near-perfect spheres of calcium carbonate;
• dogtooth spar, very large calcite crystals often found near pools that fill seasonally;
• flowstone, which can form a variety of structures, including cave bacon and drapery;
• soda straws, chandeliers, and popcorn, which form from the splattering of drops;
• helictites, which are stalactites that have a central canal with twig-like or spiral projections that appear to defy gravity;
• rimstone pools, which are small areas that build up enough deposits around their edges to contain water;
• and many more.

Occasionally (as is the case with cave bacon) they are colored due to the presence of minerals such as iron, copper, or, more rarely, manganese. Most speleothems are brown or mud-colored because of particulate inclusions from mud or silt. Dogtooth spar is a speleothem found in limestone caves that consists of very large calcite crystals resembling dogs teeth (hence the name). ... Flowstone is composed of sheetlike deposits of calcite formed where water flows down the walls or along the floors of a cave. ... A soda straw is a speleothem in the form of a hollow mineral tube. ... Cave Popcorn, or cave coral, is a very common cave formation. ... A helictite is a speleothem found in limestone caves that changes its axis from the vertical at one or more stages during its growth. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metal Group, Period, Block 8 (VIIIB), 4, d Density, Hardness 7874 kg/m3, 4. ... General Name, Symbol, Number copper, Cu, 29 Chemical series transition metals Group, Period, Block 11 , 4, d Density, Hardness 8920 kg/m3, 3. ... General Name, Symbol, Number manganese, Mn, 25 Chemical series transition metals Group, Period, Block 7 , 4, d Density, Hardness 7470 kg/m3, 6. ...

Chemistry

Most cave chemistry revolves around calcite; CaCO₃, the primary mineral in limestone. It is a slightly soluble mineral whose solubility increases with the introduction of carbon dioxide, CO₂. It is paradoxical in that its solubility decreases as the temperature increases, unlike the vast majority of dissolved solids. This decrease is due to interactions with the carbon dioxide, whose solubility is diminished by elevated temperatures; as the carbon dioxide is released, the calcium carbonate is precipitated. Calcite from Brushy Creek Mine, Missouri, USA. The mineral calcite is a carbonate of calcium corresponding to the formula CaCO3 and is one of the most widely distributed minerals on the Earths surface. ... Limey shale overlaid by limestone. ... A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... Carbon dioxide is an atmospheric gas composed of one carbon and two oxygen atoms. ...

Most other solution caves that are not composed of limestone are composed of gypsum (calcium sulfate), the solubility of which is positively correlated with temperature.

As climate proxies

Samples can be taken from speleothems to be used like ice cores as a proxy record of past climate changes [1]. A particular strength of speleothems in this regard is their unique ability to be accurately dated over much of the late Quaternary period using the uranium-thorium dating technique. Stalagmites are particularly useful for palaeoclimate applictions because of their relatively simple geometry and because they contain several different climate records, such as oxygen isotopes and trace cations. An ice core is a tube of ice removed from an ice sheet. ... The Quaternary Period is the geologic time period from the end of the Pliocene Epoch roughly 1. ... Uranium-thorium dating, also often referred to as thorium-230 dating, uranium-series disequilibrium dating or uranium-series dating, is a radiometric dating technique commonly used to determine the age of carbonate materials such as speleothem or coral. ... Isotopes are atoms of a chemical element whose nuclei have the same atomic number, Z, but different atomic weights, A. The word isotope, meaning at the same place, comes from the fact that isotopes are located at the same place on the periodic table. ... ...