LOGGING REQUIREMENTS
In order to log this EarthCache, send me your answers to the following questions either through email or messaging from my profile page.
1: What size group does most of the sand on this beach fit into?
2: From the larger pieces on this beach, is there more coral or shells present?
3a: Do you think the sand is done breaking down here or will it continue?
3b: Please give reasons for your answer to 3a.
4: Post a pic of you or a signature item with the beach in the background.
HAWAIIAN BEACH SAND
Hawaii's beaches have a variety of sand types, including black, white, red, and green sand.
Black sand is formed from the erosion of volcanic rocks.
White sand is made up of the carbonate shells and skeletons of marine organisms.
Kaihalulu Beach in Hana, Hawaii is one of the few red sand beaches in the world. The sand is iron-rich and gets its color from the slowly disintegrating sandy stones of a cinder cone hill.
Papakōlea Beach is one of only four green sand beaches in the world and the only one in the US. The green sand is made of olivine, a silicate material found in lava.
While Hawaii might have the most diverse sand options in the country, white sand still makes up the majority of the beaches. The sand on these beaches is actually tiny pieces of coral, algae, urchin spines and shells. Ko'a (coral) is a tiny animal that creates it's own hard home around it. A coral reef is made by millions of ko'a all building new tiny homes on top of the old ones over thousands of years. Animals such as the uhu (parrot fish) and the 'ina uli (pastel sea urchin) create sand by scraping and boring into the reef for food and shelter. Sand is also full of tiny hard-shelled single celled organisms called foaminifera, sea snails and algae like halimed that hardens after it dies. Sand in Hawaii is a natural substance that actually grows on the reef.
FROM SHELLS AND CORAL TO SAND
Shells and pieces of coral are moved around on the ocean floor by currents, waves and tides all the while breaking them down. Eventually they wash up on shore. Pounding waves continue to break them into smaller, sand-sized pieces.
SIZE MATTERS
In the United States, sand is commonly categorized into five size groups:
Very fine sand: 1⁄16–1⁄8 mm in diameter
Fine sand: 1⁄8–1⁄4 mm in diameter
Medium sand: 1⁄4–1⁄2 mm in diameter
Coarse sand: 1⁄2–1 mm in diameter
Very coarse sand: 1–2 mm in diameter
references
https://dlnr.hawaii.gov/
https://www.randyripley.com/
https://en.wikipedia.org/wiki/Grain_size
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