Karst topography
Karst topography is a geological formation shaped by the dissolution of a layer or layers of soluble bedrock usually carbonate rock such as limestone or dolomite. Subterranean drainage may limit surface water with few to no rivers or lakes. Many karst regions display distinctive surface features, with sinkholes being the most common. However, distinctive karst surface features may be completely absent where the soluble rock is mantled, such as by glacial debris or confined by one or more superimposed non-soluble rock strata. Some karst regions include thousands of caves, although evidence of caves large enough for human exploration is not a required characteristic of karst.
Types and formation
A cave or cavern is a hollow place in the ground, especially natural underground space large enough for a human to enter. Caves form naturally by the weathering of rock and often extend deep underground.
solution caves
Solutional caves are the most frequently occurring caves and such caves form in rock that is soluble, such as limestone, but can also form in other rocks, including chalk, dolomite, marble, salt, and gypsum. Rock is dissolved by natural acid in groundwater that seeps through bedding-planes, faults, joints and so on. Over geological epochs cracks expand to become caves and cave systems.
primary caves
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. Examples of such caves can be found in the Canary Islands, Jeju-do, the basaltic plains of Eastern Idaho and other places. Kazumura Cave near Hilo, Hawaii is a remarkably long and deep lava tube; it is 65.6 km long (40.8 mi).
How caves form
Cave formation begins when rainwater absorbs carbon dioxide as it falls through the atmosphere. Rain water must have carbon dioxide to become acidic. It must be acidic to chemically react to the limestone bedrock. Rainwater is absorbed by the soil into the ground.
As rainwater comes through the soil it absorbs more carbon dioxide that is being produced by plants that are dead. This changes the ground water to a weaker form of carbonic acid (H2O + CO2 = H2CO3). As it travels down through the ground it comes to solid rock. When the rock is limestone or dolomite caves can form.
The water reacts chemically with limestone and slowly a larger and larger space will form. This happens because the rocks are made of calcium carbonate (CaCO3). This is what you call chemical erosion.
As the space becomes larger and larger the water can flow through. As it flows it erodes. Physical erosion washes away rock and sand. This is what makes a cave larger and forms an underground stream. Finally over hundreds of thousands of years or even millions of years the cave is formed.
Erosion
Erosion is the process by which soil and rock are removed from the Earth's surface by natural processes such as wind or water flow, and then transported and deposited in other locations.
In this particular area at GZ, Water has caused most of the Erosion here. Springs are both caused by erosion and causes of erosion.
Types of Erosion:
Splash Erosion: Small soil particles are detached and sent airborne through the impact of raindrops on soil.
Sheet Erosion: Raindrops break apart the soil structure and it's moved down-slope by water that flows overland as a sheet rather than definitive channels. This occurs frequently during cloud bursts.
Rill Erosion: This process develops small, short-lived, concentrated flow paths. These paths create a sediment source and delivery system for hill-slope erosion. Areas where precipitation rates exceed soil infiltration rates are more prone to this type of erosion.
Gully Erosion: Water flows in narrow channels during or directly following heavy rains or melting snow. The gullies can erode to considerable depths.
Valley or Stream Erosion: Continual water flow alongside land (along a linear feature) creates this type of erosion. It extends downward, deepening a valley, and head-ward, extending the valley into the hillside. This occurs most frequently in times of flooding.
Bank Erosion: Over time, banks of rivers and streams are naturally worn down.
Freezing and thawing: Cold weather causes water trapped in tiny rock cracks to freeze and expand, breaking the rock into several pieces.
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