Calthemite Stonicles at Ft Jefferson/Dry Tortugas EarthCache

This Earthcache is located at Fort Jefferson and Dry Tortugas National Park. Getting here will require some planning due to its location. It was placed with permission from Glenn D. Simpson, Park Manager Dry Tortugas National Park. Once here, you may never want to leave. Please observe all park rules, hours and stay away from "area closed" signs. Please DO NOT touch the stalactites as they are pretty fragile

This island was discovered by Spaniard Ponce De Leon in 1513. It was first named Las Tortugas (The Turtles) due to the abundance of sea turtles. The word 'Dry' was soon added to mariners' charts to warn of the lack of fresh water.
Fort Jefferson was constructed to protect the important Gulf of Mexico shipping lanes and was one of the largest forts ever built. Nearly thirty years in the making (1846-1875), Fort Jefferson was never finished nor fully armed. It was a vital link in a chain of coastal forts that stretched from Maine to California. Fort Jefferson was a brilliant and undeniable symbol that the United States wanted to be left alone. Though never attacked, the fort fulfilled its intended role. It helped to protect the peace and prosperity of a young nation. It is the largest masonry structure in the Americas, and is composed of over 16 million bricks. Fort Jefferson was used as a military prison during the Civil War. During this time, it was "home" to Dr. Samuel Mudd, who was convicted of complicity in the assassination of President Abraham Lincoln.

The Earthcache Lesson
You have heard of Icicles but have you ever heard of stonicles (Stone Icicles)? No? That's probably because they are called Stalactites. What is a stalactite?
Stalactites are deposits of calcium carbonate (lime) that are usually found in limestone caves. They hang downwards like an icicle.

In a cave the precipitation of calcium carbonate forms both Staligtites and Staligmites. In a manmade cave (cement cave), these deposits are known as Calthemites. A Calthemite is a deposit derived from concrete and form to look like cave Stalactites.

This Fort serves as a Limestone cave. Made up of 16 million bricks and mortar, most that were made in Pensacola, Florida. Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite. Mortar is traditionally a mix of lime and sand. Lime consists of calcium oxide, gained from heating limestone. Over time this structure has been exposed to water and the calcium oxide reacts with it to form calcium hydroxide. The rainwater carries calcium hydroxide in a solution, which when it comes into contact with air, it reacts with carbon dioxide and calcium carbonate is precipitated. What you can see on the ceiling is calcium carbonate Calthemites. Once the Fort was built, the ceilings were covered with earth to fortify it. Now as the rain water seeps through the earth and then through the ceiling of the fort, we see the Stalactites and Stalagamites.

Stalactites and stalagmites are created when water seeps through the earth layers. Some useful associations are that stalactites hang "tite" while stalagmites hold "mite", or that stalactites are on the ceiling, stalagmites on the ground. Stalactites are usually long and thin. Stalagmites are usually a bit shorter and not so thin as the hanging stalactites. Stalactites and stalagmites sometimes grow to touch each other to form what is called a column or stalagnate.

The growth rate for these objects is 0.1 to 0.2 milimetres a year under normal earth conditions.

The growth rate for Calthemites can be up to 2 millimeters per day in optimal environments. The growth rate can vary considerably due to a wide range of chemical and physical conditions

Logging Requirements:
Now to get credit for this earthcache you will need to answer some questions. Answers need to be e-mailed to the owner of the cache, DO NOT post your answers on the cache page.

1 - First, list the name of this earthcache in the first line of your email. Also, list the number of people in your group.
2 - At the posted coordinates, estimate the length of longest Calthemite Stalactite you see here (without touching it)
3 - Given the growth rate mentioned above, how long do you think the longest one has been growing here? Does this seem likely or does this suggest these objects are growing at a faster rate? Why would this be?
4 – Do you see any drips occurring?
5 - What would you normally expect to find forming below a Calthemite Stalactite?
6 - What happens if this object connects with the Calthemite Stalactite?
7 - At waypoint 2, estimate the height of the Calthemite Stalagmite, without touching it.
8 - Not required, but we would love to see a pic of you with your GPS posing at the Fort, please no pics with spoilers

Please observe all posted rules when visiting Dry Tortugas National Park.

PLEASE NOTE: I will not be sending follow up requests for answers. If you do not complete the requirements,your log will be deleted. In order to claim this Earth Cache, you must follow through with the requirements, not just visit the site.

Team Rumble has earned GSA's highest level:

Be sure to check out the Earthcache Master program at Earthcache Masters