EARTHCACHE REQUIREMENTS
Each cacher must send his/her own answers BEFORE logging a find. ... "Geocachers must complete the tasks before they log the EarthCache as found." (4.3. EarthCache logging tasks)
Enjoy the journey (learning adventure) as well as the destination (smiley earned). Remember to take only pictures and leave only footprints. To get credit for this Earthcache, complete the following tasks:
The National Seashore - Man vs Nature series gives three examples of evidence of Barrier Island Movement.
NOTE: Answers via message -and- two log signature pictures are required to post a find for this cache.
LIGHTHOUSE
1. MESSAGE ... Based on the reading - What evidence of Barrier Island Movement is represented here?
2. MESSAGE ... Based on the reading - The lighthouse warns ships of the Diamond Shoals. Why are these shoals considered one of the most dangerous sections along the Atlantic Coast?
3. MESSAGE ... Calculate the annual rate of movement between 1870 and 1970. Then predict when the lighthouse will have to be moved again to preserve it.
LOG …. Take a picture of you or your signature item at the Lighthouse. This picture is your log signature.
BEACH - Follow the path to the beach -or- drive to the beach parking area.
4. MESSAGE ... Stand ankle deep in the water. a. Describe what you are experiencing. Include both the water and the sand. b. How does what you are experiencing relate to the necessity of moving the lighthouse?
LOG …. Take a picture of you or your signature item at the Beach. This picture is your log signature.
OPTIONAL - Please respect the time and effort involved in creating this earthcache by adding A B C D to your log.
A. FOUNDATION STONES ... 1. Based on the reading, what is the average size and weight of these stones that once supported the lighthouse? / 2. Take a picture of your favorite stone and explain why you selected this stone.
B. JOURNEY OF THE MIND ... Science explains what we observe. Walk to any place you choose along the Beach. See Experiencing the Ocean for ways to enjoy and understand the ocean.
C. JOURNEY OF THE HEART ... Art shares our personal experience of what we see. Share something special you found on site, and why it is special to you. This is a memorable addition to your log and will make other hearts smile.
Journeys of Heart and Mind ...
Stories to Touch the Heart and Puzzles to Challenge the Mind / Rainbow Tree Story
THANK YOU Ranger Stephanie Dematteo for permission to share this learning adventure.
BARRIER ISLANDS
Barrier Islands are long, narrow islands that form when a sandbar has built up enough to break through the water's surface. Along the eastern coast in the Atlantic Ocean lie these long narrow islands built from sand. They lie parallel and close to the mainland, protecting it from the powerful forces of wind and water. These islands are constantly being shaped by accretion (sand building up to create new island structures), and erosion (waves, currents, tides, storms).
Currents and storms work to continuously reshape the land. Longshore currents transport sand south along the coast. In the winter, sand is pulled from dunes and beaches depositing it into offshore sand bars thus reducing beach width. This process is reversed during milder summer weather, as gentler wave action acts to restore the shoreline. As land is lost on the front side of the island. it is usually gained on the back side. The combination of these processes continually moves the island southwest.
profile of a typical barrier island
MOVEMENT
The islands move southwest a few feet each year. This is caused by the ever changing actions of wind and water. This movement is due to oceanic drift caused when waves approach a beach at an angle (longshore currents) resulting in lateral movement of sediment (longshore drift). Littoral drift is the combination of longshore currents and longshore drift within the surf zone. This zone is the region of breaking waves responsible for 80%-90% of littoral transport.
CAPE HATTERAS LIGHTHOUSE ... VIRTUAL TOUR
"The Cape Hatteras Lighthouse protects one of the most hazardous sections of the Atlantic Coast. Offshore of Cape Hatteras, the Gulf Stream collides with the Virginia Drift, a branch of the Labrador Current from Canada. This current forces southbound ships into a dangerous twelve-mile long sandbar called Diamond Shoals. Hundreds and possibly thousands of shipwrecks in this area have given it the reputation as the Graveyard of the Atlantic."
Construction of a lighthouse at Cape Hatteras was first authorized in 1794 when Congress recognized the danger posed to Atlantic shipping. It was 90' tall, made of sandstone, and lit by a whale oil lamp. It was ineffective because it was too short, the sandstone blended with the background, and the signal was not strong enough to reach mariners.
The Cape Hatteras Lighthouse received the famous black and white stripe daymark pattern in 1873. This distinctive paint pattern (daymark) and light sequence of flashes every 15 seconds (nightmark) allows mariners to recognize it from all others during the day and night.
"When completed in 1870, the Cape Hatteras lighthouse was located a safe 1,500 feet from the ocean. Even then, however, storm-driven tides completely washed over Hatteras Island, eroding sand from the ocean side of the island and depositing it on the sound side. By 1970, this process, which has caused the gradual westward migration of the Outer Banks for at least the past 10,000 years, left the lighthouse just 120 feet from the ocean’s edge and almost certain destruction."
To preserve the lighthouse, it was moved to its present location. in 1999. The lighthouse was moved 2,900 feet in 23 days and now lies 1,500 feet from the seashore, its original distance from the sea.
CAPE HATTERAS FOUNDATION
"The original foundation was about 7-½' deep and was made of 6"x12"x12' crossed, yellow pine timbers submerged in water, topped with granite boulders cemented together. The foundation below the present lighthouse is a 60'x60'x4’ steel reinforced concrete pad, plus five feet of 147,000 high-density bricks and 1-½ to 2 feet of rock." At the waypoint, you can view the original granite foundation stones ranging from 2100 to 5300 pounds each.
According to the rangers, the stones were not locally sourced, but transported.
DIAMOND SHOALS
The Diamond Shoals are a cluster of shifting, underwater sandbars that are located just off the coast of Cape Hatteras, but which extend for miles in varying directions, depending on the local currents. Within the space of 100 yards or less, water depth goes from 35-40 feet to 12 feet making it one of the most dangerous sections along the Atlantic Coast.
These shoals were formed by Hatteras Island's proximity to both the Labrador Current and the Gulf Stream. The collision of these currents forms very turbulent waters and a large expanse of shallow sandbars 12 miles long extending some 14 miles offshore. Because these sandbars are hidden beneath the waves and are always changing formation and depth, they are responsible for hundreds of shipwrecks earning the nickname of the "Graveyard of the Atlantic."
It wasn't until the construction of the current 1870 Cape Hatteras Lighthouse that the number of shipwrecks finally dwindled. This is because the 193' foot tall structure's first order Fresnel lens was strong enough and distinct enough to reach visitors traveling up to 30 miles offshore. The Cape Hatteras Lighthouse stands as a sentinel protecting this hazardous section of the Atlantic Coast.
RESOURCES ... Wikipedia / Cape Hatteras Light Station / Cape Hatteras National Seashore / Accretion Erosion Avulsion / Barrier Islands Formation / Diamond Shoals / Overwash / Sandbar / Shoal / Shifting Sands / Storms Hurricanes / Reading the Beach / Reading the Waves / Rip Currents / Trail / Wave Terms