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A karst topography is that which composes of limestone and its associated features and structures.•Karst topography and caves develop in limestone rocks due to their solubility in dilute acidic groundwater.•The solubility of limestone in water and weak acid solutions leads to karst landscapes.•Regions overlying limestone bedrock tend to have fewer visible above-ground sources (ponds and streams), as surface water easily drains downward through joints in the limestone.•While draining, water and organic acid from the soil slowly (over thousands or millions of years) enlarges these cracks, dissolving the calcium carbonate and carrying it away in solution.•Most cave systems are through limestone bedrock.•Cooling groundwater or mixing of different groundwater will also create conditions suitable for cave formation.Karst topography occurs when the underlying bedrock is dissolved. The bedrock is made of gypsum, limestone or dolomite. This causes sinkholes and caverns to form.
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.
Caves in limestone are formed by water, collected by ground-water percolating into them &/or by swallowed streams. Even if the formative stream has long ceased to flow the cave will still collect percolating ground-water, which moves through joints and other discontinuities within the rock mass over the cave..
Principally, as by far the majority of the world's caves are formed in limestone uplands, by dissolution of the rock's calcium carbonate by slightly acid rain-water seeping through the joints and bedding-planes. These, and other discontinuities such as faults and shale bands, provide a "leak path" for the initial penetration of water into the rock mass, though the water also has to find an outlet at a lower altitude from the inlet for flow to take place. . In time the water forms discrete conduits along the joints etc through the rock, and these coalesce to develop passages and chambers. The passages will continue to develop as long as they carry their streams. . This can happen only in soluble rocks: limestone and gypsum. Caves in other, insoluble, rocks are developed by other mechanisms.
water can develop pot holes
Stalgmited and stalactites develops by the desposition of layers of calcium carbonate and mineral solutions on the interior cave at certain pressure , temperature and PH conditions
Acidic ground water (rain-water that has absorbed atmospheric carbon dioxide to form carbonic acid) dissolving the limestone as it flows through the joints & other discontinuities in the rock mass. As well as forming the cave passages, the calcite held in solution may precipate on exposure to the cave air as the solution emerges from a joint in the cave roof, to develop stalactites & stalagmites.
Calcite rather than limestone - the crystalline version of calcium carbonate which is limestone's primary constituent. However it is only being deposited in speleothems (stalactites and stalagmites). . Elsewhere in the cave, limestone is being removed, not deposited, by any stream(s) still flowing in the the system. . The limestone which holds the cave was deposited then uplifted into the highlands whose eroded forms you see now, long before the cave started to develop.
Stalgmited and stalactites develops by the desposition of layers of calcium carbonate and mineral solutions on the interior cave at certain pressure , temperature and PH conditions
Mineral deposits which develop upwards from a cave floor are known as stagmites. Deposits which form from the ceiling are stalactites.
Slightly acid water seeping through the joints in the limestone overlying the cave dissolves calcium carbonate form from the rock, then precipitates it as the crystalline mineral, calcite, on emerging through the cave roof. Each drop of "hard" water may leave only a few molecules of calcite, but drop after drop after drop... the deposits develop.
stalagmites are made of limestone.More precisely, they are crystalline precipitates of calcite: re-precipitated calcium carbonate dissolved from the surrounding limestone by percolating carbonic acid (water containing carbon-dioxide absorbed from the atmosphere).The formations can also be tinted by trace minerals such as iron, but the primary constituent is calcite.Related formations can develop from gypsum (calcium sulphate, also soluble in ground-water).
of course its a rock.
A karst topography is that which composes of limestone and its associated features and structures.•Karst topography and caves develop in limestone rocks due to their solubility in dilute acidic groundwater.•The solubility of limestone in water and weak acid solutions leads to karst landscapes.•Regions overlying limestone bedrock tend to have fewer visible above-ground sources (ponds and streams), as surface water easily drains downward through joints in the limestone.•While draining, water and organic acid from the soil slowly (over thousands or millions of years) enlarges these cracks, dissolving the calcium carbonate and carrying it away in solution.•Most cave systems are through limestone bedrock.•Cooling groundwater or mixing of different groundwater will also create conditions suitable for cave formation.Karst topography occurs when the underlying bedrock is dissolved. The bedrock is made of gypsum, limestone or dolomite. This causes sinkholes and caverns to form.
Both are formed by calcium carbonate dissolved in the water feeding them, precipitating out and crystallising. Therefore, since not all the mineral is deposited from each drop of water, the drips from a stalactite can develop a stalagmite below from the mineral remaining. Howver, it's not axiomatic that a stalactite will have a corresponding stalagmite, or vice-versa!
Caves form because ground water is slightly acidic and in flowing through joints, bedding-planes and faults within limestone or gypsum, dissolves the rock away. The only other rocks soluble in water are Chalk, Dolomite and Salt, but their formations do not normally support cave development - though there are a few caves known in chalk.
No. They are precipitations of calcite. Draughts may influence their shapes, and are thought one way in which helictites develop.