Why do icebergs look blue

Large amounts of dead organic matter reflect yellow light, Warren says, but just a small amount will make an iceberg shimmer like jade. Translucent, sparkling blue bergs form from particle-free seawater. Marine ice contains much less air than glacial ice, giving it gemstone clarity; bubble-filled glacial ice typically appears cloudy.

Shiny black icebergs are made of defect-free marine ice. Add in light-scattering cracks and the ice will regain its blue hue. Cracks also factor in creating striped icebergs. Fissures in the base of an ice shelf can become flooded with seawater that then freezes. If a series of cracks open simultaneously, the iceberg is streaked with bands of a single color. Blue stripes can also form on the top of glaciers when its own melt water freezes in crevices. Yellow, green and multicolored icebergs require the existence of glacial ice shelves and very cold conditions—cold enough to freeze seawater—so they arise only in Antarctica.

Bergs in the Arctic are white, or blue if their snow jackets have melted. A warming ocean could reduce the number of tinted bergs, already uncommon. But scenarios exist where marine ice could continue to form at higher ocean temperatures, says Laura Herraiz Borreguero a researcher at Southampton University, UK, who studies the melting of Antarctic ice shelves.

If the ice shelf remains intact, water could still potentially freeze to its underside because the huge, downward pressure of the shelf can alter the freezing temperature of water immediately under it.

If that surface was later exposed to a warmer ocean as it rolled over so it could be seen, it might melt quickly. It contains more than five times the glacier area of all the other Cascade volcanoes How old is glacier ice? The age of the oldest glacier ice in Antarctica may approach 1,, years old The age of the oldest glacier ice in Greenland is more than , years old The age of the oldest Alaskan glacier ice ever recovered from a basin between Mt.

Bona and Mt. Churchill is about 30, years old. Glacier flow moves newly formed ice through the entire Are today's glaciers leftovers from the Pleistocene ice age? Yes and no. It depends on which glaciers you are considering. Parts of the Antarctic Continent have had continuous glacier cover for perhaps as long as 20 million years.

Other areas, such as valley glaciers of the Antarctic Peninsula and glaciers of the Transantarctic Mountains may date from the early Pleistocene. For Greenland, ice cores and Was all of Alaska covered by glaciers during the Pleistocene Ice Age?

No--most of interior Alaska, south of the Brooks Range and north of the Alaska Range, was a non-glaciated grassland refuge habitat for a number of plant and animal species during the maximum Pleistocene glaciation.

This ice-free corridor also provided one route for humans to move into North America. Do ice worms exist? Yes, ice worms do, in fact, exist!

They are small worms that live in glacial ice in Alaska, Washington, Oregon, and British Columbia; they have not been found in glaciers elsewhere. Contrary to stories and songs, they do not give glacier ice its blue color and they don't grow to lengths of 50 feet. These myths were made popular by poet Robert Is glacier ice a type of rock? Glacier ice, like limestone for example , is a type of rock. Glacier ice is actually a mono-mineralic rock a rock made of only one mineral, like limestone which is composed of the mineral calcite.

The mineral ice is the crystalline form of water H 2 O. The situation is different for light that is not reflected, but penetrates or is transmitted into the snow. As this light travels into the snow or ice, the ice grains scatter a large amount of light. If the light is to travel over any distance it must survive many such scattering events. In other words, it must keep scattering and not be absorbed. We usually see the light coming back from the near surface layers less than 1 cm after it has been scattered or bounced off other snow grains only a few times, and it still appears white.

In simplest of terms, think of the ice or snow layer as a filter. If it is only a centimeter thick, all the light makes it through; if it is a meter thick, mostly blue light makes it through.

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