Recently, I attended a Maker Magic - Earth Class is in Session event. I came across this interesting looking boulder and while researching caches for a North Eastern US Trip, I came across exactly what this is - calthemite! Then, one of the attendees at our recent CITO, redbullfinch, had the 10% HCL solution necessary to test my hypotheses and confirm this is indeed a limestone calthemite formation! NOTE: Please do NOT perform this test yourself!
Most likely, this boulder had been under a concrete structure, from where the calthemite came. Also, the boulder was tipped 90 degree - but that will make more sense once you investigate it.
For more background on the Liv Co Vet Poppy Monument, please see the Virtual cache already placed.
The boulders around this area of Gypsy Lane all came from somewhere around Livingston County.
SPECIAL TOOL REQUIRED - TAPE MEASURE.
PLEASE SEND TO THE CO :
1) Why shouldn't you touch the examples?
2) From the lesson, what type of Calthemite do you see at the left side of this boulder? Pick out the longest one and send me its measurement, holding the tape measure in mid-air.
3) Use your hands to form a frame with thumbs touching. Above the sign pictured here or on the right side of the boulder, use that frame and count up how many decorative designs were formed from calthemite remnants that you see in that frame. (Which is most likely why this boulder was chosen for the metal monument sign.) Please send me the scientific term for this along with your count.
4) As of June 2019, earthcaches can now contain required photo logging tasks. Please provide a photo of yourself, your GPSr, or a personal item that proves that you have visited this site. PLEASE NO SPOILER PICTURES. You can take this photo with the entrance sign to the monument as your backdrop or relic.
Calthemites can and do form on rock and brick structures as we find here on this boulder. Most likely, this boulder was turned a different direction from the way it was found. The majority of calthemites are created by chemical reactions which are different from normal "speleothem" chemistry. Please DO NOT touch the formations as they are fragile and you will damage this natural process. This will preserve the calthemites since the rock buildup is formed by minerals precipitating out of the water solution onto the existing surface; skin oils can alter the surface tensions where the mineral water clings or flows, thus affecting the growth of the formation. Oils and dirt (mud, clay) from human contact can also stain the formation and change its color permanently.
Calthemites are known as secondary deposits, made up of primarily with calcium carbonate (CaCO3 ), coming from concrete, mortar or lime. They are very similar in composition and form to speleothems in limestone caves, however beneath human-made concrete structures CaCO3 deposition occurs when carbon dioxide (CO2 ) is a reactant as opposed to a product. Reactants and products are the two major components of a Chemical Reaction. Reactants are the starting material of a chemical reaction. Products are the chemical species that can be found after the completion of the reaction.
Calthemite deposits tend to take on the shapes and forms of speleothems e.g. stalactites, stalagmites, straws and flowstone. The secondary deposits derived from concrete are the result of concrete degradation, where calcium ions are leached out of the concrete in solution and redeposited on the underside of a concrete structure to form .
FLOWSTONES
Flowstones are sheetlike deposits of calcite or other carbonate minerals, formed in places that water flows down the walls or along the floors of a cave pr manmade structure like GZ. They are usually found in "solution caves", in limestone, where they are the most common speleothem. They can and do form in any type of cave where water enters that has picked up dissolved minerals.
There are two common forms of flowstones, tufa and travertine. Tufa is usually formed via the precipitation of calcium carbonate, and is spongy or porous in nature. Travertine is a calcium carbonate deposit often formed in creeks or rivers; its nature is laminated, and it includes such structures as stalagmites and stalactites.
Stalactites and stalagmites are formed where water seeps through the brick and mortar. 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,they hang from the ceiling of caves, hot springs, or man-made structures such as bridges and mines and form much more rapidly there than in the natural cave environment.
Stalactites
Stalagmites
Hyperalkaline seepage or vein filling - On both the front and the right side of the boulder, you will see some decorative designs. The calcium-laden solution (white leachate) from concrete (most likely from salt spread on roads in the winter) which found its way into the tiny fissures, often driven by pressure, is called hyperalkaline seepage, also known as vein filling. In this unique case, the cracks in the boulder were filled with this white residue thus creating these designs.
Resources:
Geocacher redbullfinch, enthusiastic amateur geologist
Wikipedia - Flowstones
Wikipedia - Concrete degredation
Rocks and Minerals by Chris Pellant