The Clearwater Post Office was dedicated on Oct 9, 1933. This Mediterranean-Revival style building was designed by Clearwater architect Theodore Skinner and built by the Palm Beach construction firm of Walt and Sinclair of Florida. It is representative of the 1930's federal works projects which reflected regional design influence and commissioned local professionals and industries. The exterior of the building is oolitic limestone quarried in the Florida Keys.
Oolite is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. The name derives from the ancient Greek word ᾠόν for egg. Strictly, oolites consist of ooids of diameter 0.25-2 mm; rocks composed of ooids larger than 2 mm are called pisolites.
Ooids are most commonly composed of calcium carbonate, but can be composed of phosphate, chert, dolomite or iron minerals including hematite. Dolomitic and chert ooids are most likely the result of the replacement of the original texture in limestone. Oolitic hematite occurs at Red Mountain near Birmingham, Alabama along wiht oolitic limestone.
They are usually formed in warm, supersaturated, shallow, highly agitated marine water intertidal environments, though some are formed in inland lakes. The mechanism of formation starts with a small fragment of sediment acting as a "seed" i.e. a piece of a shell. Strong intertidal currents wash the "seeds" around on the seabed where they accumulate layers of chemically precipitated calcite from the supersaturated water. The oolites are commonly found in large current bedding structures that resemble sand dunes. The size of the oolite reflects the time they have had exposed to the water before they were covered with later sediment.
Some exemplar oolitic limestone was formed in England durning the Jurassic period and forms the Cotswold Hills, the Isle of Portland and part of the North Yorkshire Moors.
The islands of the Lower Keys in the Florida Keys as well as some barrier islands east of Miami, bordering Biscayne Bay, are mainly oolitic limestone which was formed by deposition when shallow seas covered the area between periods of glaciation. The material consolidated and eroded during later exposure above the ocean surface.
Limestone rock has an even structure and it can therefore be cut or sculpted in any direction. This feature coupled with hardness, color and durability, give the limestone its quality as a building stone.
| I have earned GSA's highest level: |
 |
Please email the answers to the address above, for the following questions. If you don't intend to answer the questions, please do not log a find for this earth cache.
1. What species are the fossils in the limestone?
2. What colors can you see in the limestone?
3. What is in the round stone on either side of the words "United States Post Office"?
4. Estimate the size of the largest fossil you can see.
5. Does the limestone show any wear? If so what kind of wear do you see happening?
http://apps.flheritage.com/markers/markers.cfm?ID=pinellas
https://en.wikipedia.org/wiki/Oolite
http://csmres.jmu.edu/geollab/Fichter/SedRx/Rocks/oospar1.html