Nandi Waterfall Earth Cache - Cathedral Peak

Waterfalls

Waterfall is any point in a river or stream where water flows over a vertical drop or a series of steep drops.

A waterfall is a steep descent of a river or other body of water over a rocky ledge.

A waterfall is a river or other body of water's steep fall over a rocky ledge into a plunge pool below.

Waterfalls are also called cascades.

The process of erosion, the wearing away of earth, plays an important part in the formation of waterfalls.

Waterfalls themselves also contribute to erosion.

In general, the occurrence of waterfalls increases in mountainous terrain as slopes get steeper. Erosion and geology are not the only factors that create waterfalls. Tectonic movement along a fault may bring hard and soft rocks together and encourage the establishment of a waterfall.

Waterfalls are formed when rivers flow over different types of rock layers

The main steps of waterfall formation are:

• A layer of hard rock overlays a layer of softer rock.

• The softer rock is more quickly eroded by the river, creating a drop or a cliff.

• The river undercuts the hard rock, leaving an overhang that eventually collapses.

• The fallen rocks create a plunge pool at the base of the waterfall, where the river continues to erode the softer rock.

Often, waterfalls form as streams flow from soft rock to hard rock. This happens both laterally (as a stream flows across the earth) and vertically (as the stream drops in a waterfall). In both cases, the soft rock erodes, leaving a hard ledge over which the stream falls.

A fall line is the imaginary line along which parallel rivers plunge as they flow from uplands to lowlands. Many waterfalls in an area help geologists and hydrologists determine a region's fall line and underlying rock structure.

As a stream flows, it carries sediment. The sediment can be microscopic silt, pebbles, or even boulders. Sediment can erode stream beds made of soft rock, such as sandstone or limestone. Eventually, the stream'snchannel cuts so deep into the stream bed that only a harder rock, such as granite, remains. Waterfalls develop as these granite formations form cliffs and ledges

A stream's velocity increases as it nears a waterfall, increasing the amount of erosion taking place. The movement of water at the top of a waterfall can erode rocks to be very flat and smooth. Rushing water and sediment topple over the waterfall, eroding the plunge pool at the base. The crashing flow of the water may also create powerful whirlpools that erode the rock of the plunge pool beneath them.

The resulting erosion at the base of a waterfall can be very dramatic, and cause the waterfall to "recede." The area behind the waterfall is worn away, creating a hollow, cave-like structure called a "rock shelter." Eventually, the rocky ledge (called the outcropping) may tumble down, sending boulders into the stream bed and plunge pool below. This causes the waterfall to "recede" many meters upstream. The waterfall erosion process starts again, breaking down the boulders of the former outcropping.

Erosion is just one process that can form waterfalls. A waterfall may form across a fault, or crack in the Earth’s surface. An earthquake, landslide, glacier, or volcano may also disrupt stream beds and help create waterfalls.

Classifying Waterfalls

There is not a standard way to classify waterfalls. Some scientists classify waterfalls based on the average volume of water in the waterfall.

Another popular way of classifying waterfalls is by width.

Waterfalls are also classified by height.

Types of Waterfalls

One of the most popular, if least scientific, ways to classify waterfalls is by type. A waterfall's type is simply the way the descends. Most waterfalls fit more than one category.

A block waterfall descends from a wide stream.

A cascade is a waterfall that descends over a series of rock steps.

A cataract is a powerful, even dangerous, waterfall.

A chute is a waterfall in which the stream passage is very narrow, forcing water through at unusually high pressure.

Fan waterfalls are named for their shape. Water spreads out horizontally as it descends.

Frozen waterfalls are just what they sound like. For at least part of the year, the waterfall freezes.

Horsetail waterfalls maintain contact with the hard rock that underlies them.

Multi-step waterfalls are a series of connected waterfalls, each with their own plunge pool.

Plunge waterfalls, unlike horsetail falls, lose contact with the hard rock.

Punchbowl waterfalls are characterized by wide pools at their base.

The water flowing over segmented waterfalls separate as distinct streams.

How is a cave formed

A cave is a natural opening in the earth that can be explored by human. There are different types of caves formed by different processes, but the most common ones are solution caves, which are formed by the chemical reaction between groundwater and soluble rock, such as limestone or dolomite

Caves are natural openings in the earth that can be small or large, and can extend deep underground. They are formed by the dissolution of rock, especially limestone, dolomite, and marble, by water that picks up carbon dioxide from the air and the soil. The water becomes a weak acid that slowly eats away at the rock along the cracks and layers, creating cave passages. Caves that extend further underground than the opening is wide are called endogene caves, while caves that are closer to the surface are called exogene caves.

Caves are formed in a variety of ways. Most commonly, a cave is formed when rainwater collects underground. Over thousands or even millions of years, the small amount of acid in the water eats away at the surrounding rock. As the rock dissolves, a cave passage is formed

The largest and most common caves are those formed by chemical reaction between circulating groundwater and bedrock composed of limestone or dolomite. 

These caves, called solution caves, typically constitute a component of what is known as karst terrain

Caves have fascinated people for generations, but just how are caves formed? There is something unique and exciting about caves.  Prehistoric people used them for shelter, safety, and ceremony. Today, people visit them in droves, exploring their secrets. You may be wondering how these mysterious geologic formations were made.

Different Ways Caves are Formed

Caves can be formed in a variety of ways, including:

• Rainwater

• Wind erosion

• Volcanos

• Sand erosion

Most caves are formed by rainwater. Rainwater contains a small amount of weak acid called carbonic acid. It may be weak, but it is strong enough to dissolve rock – particularly a specific kind of rock called limestone.

Limestone is made from the shells of dead sea creatures, which have been pressed together over millions of years to form layers of rock. The reason caves are often made of limestone is that it dissolves easily, even in the weakest acid. These types of caves are called solutional caves, and are the most common type.

Types of Caves

The most common type of cave is formed when limestone interacts with acidic rainwater. This is called a solutional cave. However, there are other, less common cave types that exist in specific places. These include:

• Glacier caves

• Erosional caves

• Sea caves

• Lava caves

Glacier caves are sometimes called ice caves, probably because that’s what they are made of. Instead of rock, ice is melted away to form a cavern.  Melting ice and flowing water carves away at the glacier ice. What’s left behind is an empty space, a cave within a glacier.

Glacier caves don’t last nearly as long as caves made of rock. Glaciers may seem to stand still, but they are actually moving very slowly. The constant, slow movement causes the ice surrounding a glacier cave to fracture – and before you know it, the cave collapses. 

Erosional caves may sound just like solutional limestone caves, and in essence, they are – with one major difference. Instead of being formed by acidic water slowly eating away at the rock, erosional caves are carved out by a flowing stream of water. The water carries small rocks and sand. These are capable of eroding much harder rock than limestone. Erosional caves can be formed in even the hardest of rock, such as granite.

There are also erosional caves formed by the wind. That’s right, wind carrying particles of sand can whip around a cliff face, eventually carving a hole in the rock. The rock, in this case, would be a very soft sandstone, so these types of erosional caves can form fairly quickly – and disappear just as fast.

Sea caves are another type of cave found around the world. As the name implies, sea caves are formed by the eroding action of waves pounding against soft rock such as sandstone. The erosion can occur either above or below the waterline. Just like wind action in the formation of erosional caves, the grinding force of salt water is enough to wear away the rock. Sea caves also tend to have a short shelf-life. Constantly battered by sand-filled waves, sea caves often collapse, sometimes leaving a large sinkhole in their place. I used to live by a famous sea cave and over the course of a few years, the cave walls fell into the sea. Waves quickly eroded the sand away.

Lava caves are unique because they aren’t formed by carving away at the rock but are formed right along with the rock. As molten hot lava flows out of the earth, it cools. The cooled lava becomes hard – it is now rock.  Meanwhile, a flow of lava may continue under the cooled rock. Once it passes through, a cave is left behind. Lava caves are almost always tube-shaped. They are sometimes called lava tubes. Many lava caves or tubes can be found in Hawaii, a place famous for its constantly active volcanoes. Lava tubes are also out of this world – literally. Other planets, and even the moon, have formations of lava caves.  This is because no water is required in making lava caves, only molten rock.

How Long Does It Take for a Cave to Form?

Caves take thousands, or in some cases, millions of years to form.   Geologists talk about time in large chunks – a thousand years is a small amount in the big scheme of things. In the case of caves, a “quick” forming limestone cave might take 50,000 years to form. The average cave takes 100,000 years or so. Some caves take millions of years to be created. 

Two factors can influence how long it takes most caves to form.  These are:

• The hardness of the rock

• The amount of given rainfall in the area

Not all caves are made of limestone – some are made of gypsum or even hard rock like granite. So, if a cave is being formed in harder rock, it will take longer for the water and acid to erode the rock away. Softer rock like limestone and gypsum takes a shorter amount of time.

The amount of rainfall is also important. Water is a key ingredient for creating most caves. If there is a lack of water, then there is less dissolving action taking place. It will take longer to dissolve the rock.

Caves that are formed by other means, such as wind, sand, or ice, can be created much faster. As you can imagine, these types of caves might have very different timelines. When you think about how easily ice can melt, or sand can crumble, you get an idea of how fragile these caves can be. 

Formations in Caves

Inside a cave, changes are constantly occurring.  These changes take thousands or even millions of years. Because caves are typically created by groundwater seeping through rock, caves tend to be moist, dark places. The reactions between acidic water and limestone can produce a variety of formations.

Speleothems

All cave formations are called speleothems. The word “speleothem” comes from the Greek “spelaion” meaning cave and “thema” which means deposit.  It makes sense – over time, water and rock mix and deposits themselves on the walls, floor, and ceiling of the cave. The most common speleothems are:

• Stalactites

• Stalagmites

• Cave Pearls

These intricate formations are the main draw for many cave visitors, who are captivated by their bizarre, otherworldly appearance.

Stalactites

These form when water drips from the ceiling. The acidic, limestone-rich water slowly creates a sort of icicle-shaped formation which can grow to be quite long. To picture what stalactites look like, imagine bumpy, rocky icicles hanging from a cave ceiling.

Stalagmites

This type of formation begins on the ground. Water drops from stalactites hanging from the ceiling, puddling on the ground and evaporating. The minerals left behind begin to accumulate into a sort of pile. Over many years, the pile grows larger, and may eventually connect to the stalactite overhead! 

Stalagmites can look like globs of goo that have melted together to form mounds. They can also resemble broomsticks, or even totem poles.

Cave Ecosystems

You may be wondering what sorts of plants and animals can survive in a place that gets no sunlight? Cave ecosystems are extremely diverse, and just like their counterparts in forests and mountains, they rely on a complex network of creatures which feed upon one another.

In caves without sunlight, plants and animals have to get their energy from other sources. 

Interpretation of the submitted evidence rests entirely with the CO alone.

Group responses will not be acceptable.

Tasks to be undertaken in relation to this Earth Cache.

Task 1:

At the co-ordinates, Classify the Nandi waterfall type.

Task 2:

At the co-ordinates,  classify the cave type.

Task 3:

Explain how the cave was formed.

Task 4 

Describe cave and waterfall scene while sitting at bottom looking up. Include shape of cave.

Task 5:

Upload a picture of the waterfall and cave with yourself and/or team in the picture, or include some geocache item ( tracking device or display geocache name.)