The goal of this earthcache is for you to gain understanding and become familiar with the phenomenon of stalactite. In caves, stalactites and stalagmites can be millions of years old, but these stalactites can be found not only in caves, but also around newer structures.
Stalactites are formed by deposition under limestone, as lava, as ice and under (artificial and natural) cementitious structures and rocks.
Stalactite (derived from Greek and meaning "dripping"), a term given for a specific type of stalactite, which can occur in limestone caves. They are formed by each drop depositing a vanishingly small amount of limescale, variation in water flow and air flow determines shape and how slowly they grow. The stalactites are often formed first as thin straw stalactites, which have the same diameter as a single drop of water. When such a drop of water trickles out into the cave roof, degassing will occur, and some mineral will precipitate in the form of a ring around the drop. For each drop, a little more of the ring is deposited, which eventually forms a tube through which the water is passed. If the central channel were to grow again, the water would have to run on the outside of the straw, and thicker, icicle-like stalactites would form. The stalactites are usually white, but if the water is ferrous, for example, it can give a rust-yellow color.
A stalactite is a pin or a straw that grows or has grown down from the roof, as opposed to a stalagmite that grows up from the floor. The two forms can meet and grow together into columns. If the stalactite is larger than the stalagmite, there is usually less rapid water flow, and more of the limestone is sufficient to be deposited in the stalactite, than with faster water flow where the stalagmite, on the floor of the cave, grows fastest.
Limestone stalactite is formed by the deposition of calcium carbonate and water that reacts with the surrounding air. The deposition rate is a slow process and amounts to about 0.1 mm / year.
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The chemical process in a limestone cave begins with the rainwater reacting with CO2 that is in the ground so that more carbon dioxide is formed. As there are many more microorganisms in the ground than in the air, you will find 30 times more CO2 here, which is large. The carbon dioxide dissolves the limestone, which mainly consists of calcium carbonate. Thus, the rainwater will release free ions of lime and bi-carbonate further and deeper into the ground until it finally reaches the roof of the cave. When the ions come into contact with the air in the cave, they are separated from the water and form the limestone, which in turn becomes a building material for the stalactites.
When stalactites are formed on concrete, the calcium oxide in the concrete reacts with all the water, forming calcium bi-carbonate in a reaction with the carbon dioxide that is in the air, then the stalactite is formed much like in a natural cave. But because there is a much greater supply of calcium bi-carbonate when the rainwater pulls it out of concrete, these stalactites can grow much faster than those found in natural caves.
Stalactites under concrete, bridges, rock caves or the like can grow up to 1 cm. a year. In other words, the growth rate of concrete / cement based stalactites is significantly faster than stalactites in limestone caves.
The stalactite here at GZ is of the type Concrete / cement stalactite. This type of stalactite is formed when there is calcium oxide in concrete and cement. The calcium oxide itself reacts with water that penetrates into the concrete and forms a solution of calcium hydroxide. CaO + H2O → Ca (OH) 2
When the water with this calcium hydroxide has penetrated the structure and comes into contact with air and a new chemical reaction takes place when the calcium hydroxide reacts with the carbon dioxide in the air. And we get the resulting calcium carbonate that forms the stalactite. Ca (OH) 2 + CO2 → CaCO3 + H2O
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To log this cache.
To get to log this cache you will have to visit and answer the questions which are related to the coordinates given the earthcache.
When answers are collected, send them to CO for verification.
You can log immediately after answers are sent CO. If there are any questions about your answers CO will contact you.
Logs without answers to CO or with pending questions from CO will be deleted without any further notice.
Please do not include pictures in your log that may answer the questions.
Tasks:
1. Answer the questions below by visiting the coordinates.
A. Describe in your own words how the Dripstone looks like at the location, their shape and color? Can you see any stalagmites here?
B. Based on your observations, what is the length of the longest dripstones you can find?
C. Considering the growth rate of up to 1 cm. pr. years for concrete / cement dripstones. How old do you think the oldest dripstones at the location are?
D. Base your answer on: what would the age and growth of the longest dripstones here have been if it had been found in a limestone cave?
2. Take a photo of you, the group or the GPS from the location without revealing any of the answers.