This is an Earthcache – as such, there is no physical cache. Instead after examining the carrara marble sculpture at the posted coordinates you will answer 4 questions and message me the answers. This memorial is located at Meridian Park in the Columbia Heights neighborhood and is in the care of the National Park Service. Permission for this cache placement was given by the National Mall & Memorial Parks Division of Permits Management. Street parking is available if you can find it, read the signs, and remember the terrain is lighter if you approach from the north end of this hilly park.
Serenity
Serenity is a large statue is of a seated woman, her left foot resting on what appears to be a broken sword. Today she is missing her left hand and a big toe. There is graffiti in places, and the once-sharp features of her face have been chipped away at.
Serenity was sculpted by artist Josep Clarà i Ayats. Charles Deering purchased it in Paris in 1900 as a tribute to his friend Navy Lieutenant Commander William Henry Schuetze (Embarrassingly, Schuetze's name is misspelled on the statue's base). Deering ended up offering it to the United States, and Congress authorized this site here at Meridian Hill Park where it was placed in 1925. Sadly, this statue is known for being the most vandalized memorial in Washington.
Carrara Marble is a Metamorphic Rock
Metamorphic rocks start out as some other type of rocks (see rock cycle diagram below), but have been substantially changed from their original igneous, sedimentary, or earlier metamorphic form. Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot mineral-rich fluids or, more commonly, some combination of these factors.
Geologists use the term "marble" to refer to metamorphosed limestone. Marble forms when limestone is subjected to the heat and pressure of metamorphism. It is composed primarily of the mineral Calcium Carbonate (CaCO3) and usually contains other minerals, such as clay minerals, micas, quartz, pyrite, iron oxides, and graphite. Under the conditions of metamorphism, the calcite in the limestone recrystallizes to form a rock that is a mass of interlocking calcite crystals.
The Italian marble that you see here at Serenity is Carrara, named for the mountainous region where it is quarried from in northern Tuscany. This unique stone was formed by by calcite-rich shells left behind by marine organisms after they died. Those deposited remains formed limestone, which then where hidden under multi-ton layers of rock. It was there that intense heat and pressure caused the limestone to metamorphose into marble.
The characteristic swirls and veins of many colored marble varieties are usually due to various mineral impurities such as clay, silt, sand, iron oxides, or chert which were originally present as grains or layers in the limestone. Green coloration is often due to serpentine resulting from originally high magnesium limestone or dolostone with silica impurities. These various impurities have been mobilized and recrystallized by the intense pressure and heat of the metamorphism.
Degradation Caused by Natural Weathering Processes
All materials that are exposed to the outdoor environment are subject to degradation caused by natural weathering processes. Marble is particularly sensitive to degradation by acid chemicals and to weathering.
Chemical weathering is the process that breaks down rock through chemical changes. The most common agents of chemical weathering include water, oxygen, carbon dioxide, and living organisms. Chemical weathering creates holes or soft spots in rock, so the rock breaks apart more easily. Acid rains are one of the main degradation agents for marble artifacts. When carbonic acid flows through the cracks, it chemically reacts with the stone causing some of it to dissolve. Carbonic acid is especially reactive with Calcium Carbonate.
Mechanical weathering is the process of breaking big rocks into little ones. The movement of wind, water, and ice erode the surface and cause cracks. Plant roots also push into the rocks and break them apart.
Chemical and mechanical weathering often go hand in hand with mechanical weathering cracking open and exposing more surface area for chemical weathering to eat away at.
REFERENCES:
1. "Carrara Marble: Touchstone of Eternity", National Geographic Vol. 162 No. 1 July 1982
2. "Carrara marble", https://en.wikipedia.org/wiki/Carrara_marble
3. "Italian Carrara Marble", Earthcache by FlyBryFly, June 27, 2011, geocaching.com
4. Carrara Marble Quarries, earthobservatory.nasa.gov
5. "Serenity Statue", April 28, 2011, dcmemorialist.com
6. "Serenity Statue", Carter, Elliot atlasobscura.com
7. "Marble: A non-foliated metamorphic rock that forms when limestone is subjected to heat and pressure.", King, Hobart M., Ph.D., RPG, geology.com
LOGGING REQUIREMENTS:
To log this Earthcache: Read the geology lesson above, observe the geolocal feature, answer all four questions posted below, and then send to me via e-mail or messenger contacts on my Geocaching profile.
QUESTION 1. What is the primary mineral of marble that is especially reactive to carbonic acid?
QUESTION 2. What color are the swirls & veins on this statue?
QUESTION 3. The cracks that you see on the base of serenity are from which type of weathering?
QUESTION 4. Looking at the "ghost face" of this statue, do you see signs of chemical weathering or was this mostly vandalism?
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