Blood Falls

Blood Falls is a blood-red stream of salty water that flows out of the Taylor Glacier onto the frozen surface of West Lake Bonney, in the Taylor Valley of the McMurdo Dry Valleys in East Antarctica. Against the white ice, the red color looks dramatic, but it is not blood.

The red color is from iron oxide, which is basically rust. Iron-rich water that is very salty seeps out from small cracks in the ice. The water has been trapped under about 400 metres of glacier ice, in a pool of unknown size. Once it meets the air, the iron rusts and turns red.

Who found it

Australian geologist Thomas Griffith Taylor discovered the red stain in 1911, when he first explored the valley that now bears his name.

Early Antarctic explorers thought the color came from red algae, since algae can stain snow red. Later tests proved that it came from iron oxides instead, so the 'blood' is really mineral rust carried in very salty water.

Ancient seawater under the ice

The salty water seems to be old seawater, trapped when a fjord was cut off by the advancing glacier millions of years ago, during the Miocene, about 5 million years ago.

As the water froze slowly, ice crystals left the salt behind, so the leftover brine became two to three times saltier than the ocean. Because of the salt, the water stays liquid in the cold, and the glacier is not frozen to the rock beneath it.

On the globe

The model shows a glacier tongue with a blood-red stream pouring onto the ice in Antarctica.