Please read this! There is no container for this cache. This is an earthcache. There is a set of questions listed below that MUST BE ANSWERED AND THE ANSWERS NEED TO BE EMAILED OR MESSAGED TO ME! I understand this is a vacation destination so I try not to send out any requests for answers for up to 2 weeks after you post a find on this cache. Do not make me change this. If you do not understand what an earthcache is, please visit www.earthcache.org.
The Outer Banks of North Carolina are a series of barrier islands off the coast. The Outer Banks stretch from the Southeastern Virginia southward, providing a natural barrier for the North Carolina coast between the Atlantic Ocean and the North Carolina mainland. The Outer Banks stretch for 200 miles south. The Outer Banks separate Currituck Sound, Albemarle Sound, and Pamlico Sounds from the Atlantic Ocean. For the purpose of this earthcache, we will be concentrating on the Currituck Sound area.
Currituck Sound is a protected inlet of the Atlantic Ocean located in the northeastern part of North Carolina. The sound runs roughly 30 miles north to south and is between 3 and 8 miles wide. The sound is a very shallow body of water that is dotted by many islands. Currituck Sound has no direct inlet that connects it to the Atlantic Ocean as all inlets have been closed. The only wayto reach the Atlantic Ocean is by traveling south to Albemarle Sound and through Oregon Inlet.
Now that we have an understanding of the Outer Banks and Currituck Sound, let us look at the major components of this earthcache. What is tide? What is a Barrier Island? Finally, what is a sound?
What is a Tide?
A tide is the rise and fall of sea levels that are caused by the combined effects of gravitational forces on the Earth exerted by the Sun, Moon, and Earth’s rotation. The times and amplitude of the tides at any location are influenced by the alignment of the Sun and Moon. There are 2 high tides and 2 low tides each day, roughly about 6 hours apart. High tide is when the water reaches its highest level and low tide is when the water reaches its lowest levels. Tides are commonly semi-diurnal (two high waters and two low waters each day). The two high waters on any given day are typically not the same height , and similarly the two low waters are not the same height.
Tidal constituents are the net result of multiple influences impacting tidal changes over a certain period of time. These influences are, but not limited to: Earth’s rotation, position of the Moon and Sun, and the Moon’s altitude above the Earth’s equator. Conversely, cycles of days, months, and years are referred to as long period constituents.
In most locations, the largest constituent is known as the “principal lunar semi-diurnal”. This is a period of 12 hours and 25.2 minutes, or exactly half a tidal lunar day. The lunar day is slightly longer then an Earth day because the Moon orbits the same direction the Earth spins on its axis. Because of this time difference, the Moon takes approximately 24 hours and 50 minutes to return back to the same location in the sky.
Because of the gravitational field created by the Moon weakens with the distance the Moon, it exerts a slightly stronger than average force on the Earth that is facing the moon, which results in a high tide being created. On the opposite, a slightly weaker force is being exerted on the Earth, which than results in a low tide being created. As the Earth rotates, the magnitude and direction of the tidal force at any particular point on the Earth’s surface change constantly which causes the rhythmic changes in the sea surface height.
What is a Barrier Island
A barrier island is a coastal landform of sand, which forms by wave and tidal action that parallel the mainline coast. Barrier islands are long, narrow, offshore deposits of sand and sediments which are very fragile. These island are very fragile and they are constantly changing because of coastal and ecological conditions. Barrier islands are also very important to the mainland as they absorb energy from the ocean from storms. These island also create areas of protection where wetlands may flourish.
The formation of barrier islands is very complex and not completely understood yet. The most current theory is that barrier islands were formed about 18,000 years ago when the last Ice Age ended. When the glaciers melted and receded, sea levels began to rise, and flooded areas behind the beach ridges at that time. The rising water carried sediments of these beach ridges and deposited them into shallow areas just off the new coastlines. Waves and currents continued to bring sediments that built up the barrier island further. In addition, rivers washed sediments into the ocean from the mainland and these sediments also helped to build up the islands.
Barrier islands are divided up into 4 zones. These zones are: beach, dunes, barrier flat, and salt marsh. The beach is made up of sand deposited by the actions of waves. This is the side that faces the ocean. The dunes are formed from sand carried and deposited by winds. The dunes are protected naturally by plants (sea oats, bitter pancum, etc.) and artificially by fences. Primary dunes face the oceans with secondary and tertiary dunes inland. The barrier flat are formed when sediments get pushed through the dune system by storms. Grasses grow in this area to help stabilize these areas. The salt marsh are low-lying areas on the sound side of the barrier islands. The marshes are usually divided into high and low marsh areas. High marsh areas flood twice each month with the spring tides, while the low marsh areas get flooded twice each day from high tides. Cord grasses grown in the salt marsh and these are one of the most ecological productive areas on earth.
Barrier islands are critically important in migrating ocean swells and other storm events for the water systems of the mainland side of the barrier island as well as protect the coastline. Barrier islands effectively create a unique environment of relatively low energy. Multiple wetland systems such as lagoons, estuaries, and/or marshes can result from such conditions, depending on the surroundings. Without barrier islands, these wetlands could not exist as they would be destroyed by daily ocean waves and tides, as well as ocean storm events.
What is a Sound?
A sound is a body of water that is larger and deeper than a lagoon. It acts as long, wide conduit between two bodies of water. There is more flow and mixing associated with a sound and tides can be large. Because of the sheltered nature of these bodies of water, the sediments they collect provide a particularly interesting history of the coast and environmental changes. Sounds often separate a coastline from a nearby island.
Education Lesson
Now that you know what a tide is, a barrier island is, and what a sound is, in order to complete this earthcache, you will need to go to the listed coordinates above and answer the following questions. Some of the information that you are looking for will be easily found at the location, while some of the information will require you to think about your answers. If I do not receive your answers within 2 weeks of you logging this cache, I will send an email and/or message requesting for your answers. If you refuse to not answer my email and/or message within 48 additional hours and send me your answers, I will delete your find. You leave me no choice. These answers are the only way I know that you actually visited this location.
I am aware that the boardwalk is closed because of repairs needed after a recent storm. You can gather the answer for question number 3 by going to the new posted coordinates. A quick internet search for a Virginia-Pilot article from May 2011 will provide you the answer for Question 2. The rest of the questions can be done while on site and looking at the geography of the Northern Outer Banks to the mainland part of North Carolina. A Compass might be handy to help with question number 3 if you are direction-ally challenged.
The answers to these questions are REQUIRED!
1. How does the barrier island aka The Outer Banks influence the tides on Currituck Sound?
2. What causes the tidal changes within Currituck Sound? HINT: It has nothing to do with the moon, sun, and earth positions
3. At the time of your visit is the tide currently in or out?
4. What effects do the barrier islands have on the coastal areas
This is optional and doesn't take the place of sending the answers to me!!!
Optional – please post a photo of the sound at the given coordinates at the top. You do not have to include a picture of yourself in the picture.
Please send me your answers to the questions above via the message system or through email. You can email me at tdb1977geocachers@verizon.net.
This cache has been placed with permission by the North Carolina Wildlife Education Division.