Black sand explained

Black sand is sand that is black in color. One type of black sand is a heavy, glossy, partly magnetic mixture of usually fine sands containing minerals such as magnetite, found as part of a placer deposit. Another type of black sand, found on beaches near a volcano, consists of tiny fragments of basalt.

While some beaches are predominantly made of black sand, even other color beaches (e.g. gold and white) can often have deposits of black sand, particularly after storms. Larger waves can sort out sand grains leaving deposits of heavy minerals visible on the surface of erosion escarpments.

Placer deposits

Black sands are used by miners and prospectors to indicate the presence of a placer formation. Placer mining activities produce a concentrate that is composed mostly of black sand. Black sand concentrates often contain additional valuables, other than precious metals: rare earth elements, thorium, titanium, tungsten, zirconium and others are often fractionated during igneous processes into a common mineral-suite that becomes black sands after weathering and erosion.

Several gemstones, such as garnet, topaz, ruby, sapphire, and diamond are found in placers and in the course of placer mining, and sands of these gems are found in black sands and concentrates. Purple or ruby-colored garnet sand often forms a showy surface dressing on ocean beach placers.

An example of a non-volcanic black sand beach is at Langkawi in Malaysia.[1]

Basalt fragments

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 basalt fragments to build a new black sand beach almost overnight. The famous "black sand" beaches of Hawaii, such as Punaluʻu Beach and Kehena Beach, were created virtually instantaneously by the violent interaction between hot lava and sea water.[2] Since a black sand beach is made by a lava flow in a one time event, they tend to be rather short lived since sands do not get replenished if currents or storms wash sand into deeper water. For this reason, the state of Hawaii has made it illegal to remove black sand from its beaches. Further, a black sand beach is vulnerable to being inundated by future lava flows, as was the case for Hawaiʻi's Kaimū, usually known simply as Black Sand Beach, and Kalapana beaches.[3] An even shorter-lived black sand beach was Kamoamoa.[4] Unlike with white and green sand beaches, walking barefoot on black sand can result in burns, as the black sand absorbs more solar radiation.[5]

Beaches

Black sand has formed beaches in places including:[6] [7] [8]

Europe

Africa

North America

Central America

Caribbean

Asia

North Atlantic

North Pacific

South Pacific

Indian Ocean

See also

Notes and References

  1. Web site: Archived copy . 2018-06-20 . 2018-06-20 . https://web.archive.org/web/20180620180628/http://www.gsm.org.my/products/702001-101510-PDF.pdf . dead .
  2. Web site: Magma, Lava, Lava Flows, etc.. USGS. dead. https://web.archive.org/web/20100603031420/http://vulcan.wr.usgs.gov/Glossary/LavaFlows/description_lava_flows.html. 2010-06-03.
  3. Web site: Big Island: Kalapana and Kaimu Beaches; Destroyed by Lava. 2016-11-07 . 8 June 2014. dead . https://web.archive.org/web/20170503055227/http://www.hawaiicon.com/blog/big-island-kalapana-and-kaimu-beaches . 2017-05-03 . Hall. Jessica. Hawaiicon .
  4. Web site: Hawaii's Newest Black Sand Beach . 2016-11-07 . live . https://web.archive.org/web/20161108133706/http://www.deseretnews.com/article/80684/HAWAIIS-NEWEST-BLACK-SAND-BEACH.html?pg=all . 2016-11-08 . Deseret News. Associated Press. Staton. Ron. 7 January 1990 .
  5. Web site: Black sand and burnt feet: be careful on Auckland's West Coast. 100% Pure New Zealand. dead. https://web.archive.org/web/20160423055313/http://www.newzealand.com/uk/article/black-sand-and-burnt-feet-be-careful-on-aucklands-west-coast/. 2016-04-23. 2016-04-06.
  6. Web site: Top 10 Black Sand Beaches. 12 November 2008.
  7. Web site: The world's most beautiful colorful-sand beaches . 2016-02-24 . live . https://web.archive.org/web/20160306003102/http://experience.usatoday.com/beach/story/best-beaches/2015/02/05/colorful-sands/22946971/ . 2016-03-06 .
  8. Web site: Islands with Black Sand Beaches . 2016-02-24 . live . https://web.archive.org/web/20160306003007/http://traveltips.usatoday.com/islands-black-sand-beaches-105856.html . 2016-03-06 .
  9. Web site: Teixidelo, the only non-volcanic black sand beach in the world. 22 April 2021.
  10. Web site: The Best Beaches in Panama | Frommer's . 2016-02-24 . live . https://web.archive.org/web/20160303134624/http://www.frommers.com/destinations/panama/763776 . 2016-03-03 .
  11. Web site: Treasure Beach . 2023-08-11 . www.visitjamaica.com . en.
  12. Web site: The main black beach in Iceland . 22 January 2021.
  13. Web site: Isaac Hale Beach Park // Pohoiki. lovebigisland.com . 2019-04-18.
  14. Web site: Waipiʻo black sand beach . lovebigisland.com . 2016-12-13 . live . https://web.archive.org/web/20161220095513/https://www.lovebigisland.com/waipio-valley/#waipio-beach . 2016-12-20 .
  15. Web site: Oneuli Beach Black Sand Beach | Maui Hawaii . 2016-02-24 . live . https://web.archive.org/web/20160303145614/http://www.hawaii-guide.com/maui/beaches/oneuli_beach_black_sand_beach . 2016-03-03 .
  16. Web site: One'uli Black Sand Beach . 16 November 2012 . 2016-02-24 . live . https://web.archive.org/web/20160226210135/http://mauiguidebook.com/beaches/oneuli-black-sand-beach-naupaka . 2016-02-26 .

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