Soil scientist here. Black sand like this is primarily composed of basalt. It is created when lava flows hit the ocean and cool rapidly, shattering into sand-sized particles that are deposited by tidal action. Most black sand beaches are the result of a single volcanic event.
The iron in the water comes from ferrous (reduced) iron from soil the water percolated through. When exposed to the air, the reduced iron reoxidizes and flocculates, producing the brown color seen in the OP.
Neither water nor sand is particularly magnetic.
edit: My first gilding! Thanks for the gold, kind stranger!
![image showing [OC] Iceland black beach with iron rich river running through it [3264x2448]](e469b6c2-ee7b-5a74-aba0-9a9c5b69e292_Ricokjx.jpg)
uncertainusurper on October 5th, 2017 at 23:07 UTC »
The infamous Rusty Rivers, this is coincidentally my porn moniker.
derpallardie on October 6th, 2017 at 01:13 UTC »
Soil scientist here. Black sand like this is primarily composed of basalt. It is created when lava flows hit the ocean and cool rapidly, shattering into sand-sized particles that are deposited by tidal action. Most black sand beaches are the result of a single volcanic event.
The iron in the water comes from ferrous (reduced) iron from soil the water percolated through. When exposed to the air, the reduced iron reoxidizes and flocculates, producing the brown color seen in the OP.
Neither water nor sand is particularly magnetic.
edit: My first gilding! Thanks for the gold, kind stranger!
PikpikTurnip on October 6th, 2017 at 01:14 UTC »
The perspective here is really weirdin' me out.