Welcome to St. Croix!
This is an Earthcache; there is no physical cache to find. You will not have to enter Fort Frederik-the answers can be found on the beach side of the fort.
To claim this cache, please email me (in English) with answers to the two questions. "Found" logs without a corresponding email will be deleted. If emailing on behalf of multiple geocachers, please note their geo-names in your email. In addition to the two required answers, there is a photo requirement. Online logs without a photo will be deleted.
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Types of rocks: Our planet consists of three types of rocks: Igneous, Sedimentary, and Metamorphic. Igneous rocks are rocks that have solidified from magma or lava upon cooling. They can be intrusive (solidified from magma underground) or extrusive (solidified from lava at or near the surface). Most of the earth's crust is formed from igneous rock. One rock type in this category is granite.
Sedimentary rocks are formed by the accumulation of small to large particles derived from all 3 types of rocks and in some cases, organic material and then undergoes compaction, cementation, or evaporation. These particles are deposited at the earth's surface and within bodies of water while being transported by the wind, water, ice, mass movement, and glaciers. There are three classifications of sedimentary rocks: organic, clastic, and non-clastic. Examples of organic sedimentary rocks are coal and limestone, while examples of clastic include shale and conglomerate. Non-clastic includes rock gypsum and rock salt.
Metamorphic rock is an igneous, sedimentary, or other metamorphic rock that has been squeezed by incredible pressure deep underground or exposed to very high temperatures altering its structure, mineral alignment or chemical composition. Examples include slate, quartzite, and marble.
The island of St. Croix: The island of St. Croix is 84 square miles in size, 22 miles long and a little more than six miles at its widest point. The terrain on the east end of the island is rocky and arid with short, grassy hillsides and cacti. On the west end, there are large fruit trees and ferns.
St. Croix’s highest peak is Mount Eagle, which is 1088 feet high. Although the St. Croix terrain is comprised of some volcanic material, Mount Eagle is not a volcano. It is believed that the volcanic rocks and material on St. Croix actually came from neighboring islands including St. Thomas, over 40 miles away.
The oldest visible rocks on St. Croix are the alternating dark and light banded sedimentary rocks of the Caledonia Formation, named for the Caledonia Valley. The formation is present in several areas of St. Croix, including Frederiksted. The dark colored rocks are either mudstones (very fine-grained rocks composed of silt and clay) or, less frequently, silicified mudstone or chert. Approximately 60%-70% of the Caledonia Formation is composed of bluish-gray and black mudstone. Lighter colored rocks are sandstones and conglomerates.
The mineral composition of the sand and conglomerate layers suggests that they are derived in large part from the erosion of volcanic rocks. Some shallow-water fossils (including snails, clams, and corals) are mixed with the volcanic debris.
These coordinates will take you to the beach in front of Fort Frederik, which was built by the Danish between 1752 and 1760 to protect the Virgin Islands from piracy. Despite their official neutrality during the American Revolution, many residents of the Danish Islands gave their moral and financial support to the cause of American independence. One of Fort Frederik’s cannons (probably the one aimed at your cruise ship) fired the first “unofficial” salute to the new flag of the United States on October 25, 1776.
Do not include your answers in your online log, even if encrypted.
Have fun!
1. Directly in front of Fort Frederik you will see sedimentary rock below the water. Is this evidence of the Caledonia Formation? How can you tell?
2. Even though the sides of the walls of Fort Frederik are painted, you can see the raw material used to construct the fort by observing the shorter walls from the top. Based on what you have learned about the types of rocks on our planet, what type of rock was used to construct this fort?
3. Take a picture of you or your group on the beach with Fort Fredrick in the background. Alternatively, you can take a photo of you or your group in front of the Buddhoe Park Bandstand. This is a required task. The photo must be posted with your "Found" log. Do not send me your photo. Failure to post a picture will cause your log to be deleted without further explanation.
Many thanks to Nukeworker for assisting me with this EC. Nukeworker ROCKS!