***Important Note: Do not go onto Private Property. There is a winding horse path through the trees to the beach.
Welcome to Vieques Island, a beautiful islet off of Puerto Rico. And welcome to the lovely Playa Negra, Black Sands Beach.
When you arrive to Playa Negra you will see traces of black sand contrasting with shades of deep golden sand being touched by foamy white waters.
You don’t have to fly all the way to Hawaii to appreciate and experience what it feels like to sink your toes in black sand, the island of Vieques was blessed with black sand beaches too. Areas on the island like Playa Negra are volcanic and some of this amazing volcanic material is washed down through a quebrada (stream) during heavy rains which ends up at this beach on the island.
If you take some time to look at the landscape of Vieques, it is obvious to see that much of Vieques is made from the lifting of tectonic plates; you’ll see lots of limestone and layers of sediment. But the island also had some volcanic activity, hot magma pushed up through the plates in the ocean floor. Some obvious signs of that volcanic activity would be the rocks of Puerto Ferro, and this black sand beach. The black sand is very fine (but very heavy) volcanic material that runs down the volcanic areas of the island (mainly Monte Pirata) along with rain run-off and ends up in a small stream (Quebrada Urbana), where it eventually gets pushed out onto Playa Negra.
When lava contacts water, it cools rapidly and shatters into sand and fragmented debris of various size. Much of the debris is small enough to be considered sand. A large lava flow entering an ocean may produce enough black sand fragments to build a new black sand beach almost overnight.
In order to log this earthcache, answer the following questions.
1. What is a typical base material that contributes to the appearance of a black sands beach?
2. Bring a magnet with you. Tell me whether the black sand is magnetic or not. If you don't have a magnet, describe to me if the black sand is finer or more course that the normal white sand nearby.
3. What is the estimated width of Playa Negra from the entry path to the waterline?