Firn core with an ice lens collected on Gulkana Glacier during spring 2019 mass balance field work. Gulkana Glacier is located along the south flank of the eastern Alaska Range.
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 (H2O). Most glacier ice forms through the metamorphism of tens of thousands of individual snowflakes into crystals of glacier ice. Each snowflake is a single, six-sided (hexagonal) crystal with a central core and six projecting arms. The metamorphism process is driven by the weight of overlying snow. During metamorphism, hundreds—if not thousands—of individual snowflakes recrystallize into much larger and denser individual ice crystals. Some of the largest ice crystals observed at Alaska’s Mendenhall Glacier are nearly one foot in length.
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Related
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 related data suggest that all of southern Greenland and...
How do we know glaciers are shrinking?
Repeat photography and aerial / satellite photo analysis provide evidence of glacier loss in terms of shape and area. The USGS Benchmark Glacier project has collected mass balance data on a network of glaciers in Alaska, Washington, and Montana for decades, quantifying trends of mass loss at all sites. Extensive field data collection at these sites includes twice yearly visits to measure seasonal...
How old is glacier ice?
The age of the oldest glacier ice in Antarctica may approach 1,000,000 years old The age of the oldest glacier ice in Greenland is more than 100,000 years old The age of the oldest Alaskan glacier ice ever recovered (from a basin between Mt. Bona and Mt. Churchill) is about 30,000 years old. Glacier flow moves newly formed ice through the entire length of a typical Alaskan valley glacier in 100...
How much of the Earth's water is stored in glaciers?
About 2.1% of all of Earth's water is frozen in glaciers. 97.2% is in the oceans and inland seas 2.1% is in glaciers 0.6% is in groundwater and soil moisture less than 1% is in the atmosphere less than 1% is in lakes and rivers less than 1% is in all living plants and animals. About three-quarters of Earth's freshwater is stored in glaciers. Therefore, glacier ice is the second largest reservoir...
How would sea level change if all glaciers melted?
There is still some uncertainty about the full volume of glaciers and ice caps on Earth, but if all of them were to melt, global sea level would rise approximately 70 meters (approximately 230 feet), flooding every coastal city on the planet. Learn more: USGS Water Science School: Glaciers and Icecaps National Snow and Ice Data Center: Facts about Glaciers U.S. Global Change Research Program: Sea...
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 Service and the annual Cordova Iceworm Festival in...
Why is glacier ice blue?
Glacier ice is blue because the red (long wavelengths) part of white light is absorbed by ice and the blue (short wavelengths) light is transmitted and scattered. The longer the path light travels in ice, the more blue it appears. Learn more: USGS Water Science School - Glaciers: Things to Know
Firn core with an ice lens collected on Gulkana Glacier, Alaska.
Firn core with an ice lens collected on Gulkana Glacier during spring 2019 mass balance field work. Gulkana Glacier is located along the south flank of the eastern Alaska Range.
Jonathan Cohl holding a piece of ice at Delaware River
Northeast Region Photo Contest Winner | March 2019 | People
Jonathan Cohl holding a piece of ice from Delaware River at Frenchtown, NJ
Northeast Region Photo Contest Winner | March 2019 | People
Jonathan Cohl holding a piece of ice from Delaware River at Frenchtown, NJ
Bottom of the Ice Core
Craig Lee holds the ice drill with the end of the first ice core segment exposed. The sample will next be measured, logged, and processed in the field.
Craig Lee holds the ice drill with the end of the first ice core segment exposed. The sample will next be measured, logged, and processed in the field.
Wolverine Glacier Ice
Photo of Wolverine Glacier ice. Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, a "benchmark glacier" in Alaska.
Photo of Wolverine Glacier ice. Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, a "benchmark glacier" in Alaska.
Degrading ice wedges, Ikpikpuk River Delta on North Slope of Alaska
Degrading ice wedges on the Ikpikpuk River Delta on the North Slope of Alaska.
Degrading ice wedges on the Ikpikpuk River Delta on the North Slope of Alaska.
Sea ice in the Chukchi Sea, Alaska
Sea ice in the Chukchi Sea in 2013.
Sea ice in the Chukchi Sea in 2013.
Broken Ice
Ice is pushed away from the hull of the Coast Guard Cutter Healy Sept. 1, 2009.
Ice is pushed away from the hull of the Coast Guard Cutter Healy Sept. 1, 2009.
Arctic Sea Ice
Image of sea ice along the Arctic Ocean.
Related
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 related data suggest that all of southern Greenland and...
How do we know glaciers are shrinking?
Repeat photography and aerial / satellite photo analysis provide evidence of glacier loss in terms of shape and area. The USGS Benchmark Glacier project has collected mass balance data on a network of glaciers in Alaska, Washington, and Montana for decades, quantifying trends of mass loss at all sites. Extensive field data collection at these sites includes twice yearly visits to measure seasonal...
How old is glacier ice?
The age of the oldest glacier ice in Antarctica may approach 1,000,000 years old The age of the oldest glacier ice in Greenland is more than 100,000 years old The age of the oldest Alaskan glacier ice ever recovered (from a basin between Mt. Bona and Mt. Churchill) is about 30,000 years old. Glacier flow moves newly formed ice through the entire length of a typical Alaskan valley glacier in 100...
How much of the Earth's water is stored in glaciers?
About 2.1% of all of Earth's water is frozen in glaciers. 97.2% is in the oceans and inland seas 2.1% is in glaciers 0.6% is in groundwater and soil moisture less than 1% is in the atmosphere less than 1% is in lakes and rivers less than 1% is in all living plants and animals. About three-quarters of Earth's freshwater is stored in glaciers. Therefore, glacier ice is the second largest reservoir...
How would sea level change if all glaciers melted?
There is still some uncertainty about the full volume of glaciers and ice caps on Earth, but if all of them were to melt, global sea level would rise approximately 70 meters (approximately 230 feet), flooding every coastal city on the planet. Learn more: USGS Water Science School: Glaciers and Icecaps National Snow and Ice Data Center: Facts about Glaciers U.S. Global Change Research Program: Sea...
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 Service and the annual Cordova Iceworm Festival in...
Why is glacier ice blue?
Glacier ice is blue because the red (long wavelengths) part of white light is absorbed by ice and the blue (short wavelengths) light is transmitted and scattered. The longer the path light travels in ice, the more blue it appears. Learn more: USGS Water Science School - Glaciers: Things to Know
Firn core with an ice lens collected on Gulkana Glacier, Alaska.
Firn core with an ice lens collected on Gulkana Glacier during spring 2019 mass balance field work. Gulkana Glacier is located along the south flank of the eastern Alaska Range.
Firn core with an ice lens collected on Gulkana Glacier during spring 2019 mass balance field work. Gulkana Glacier is located along the south flank of the eastern Alaska Range.
Jonathan Cohl holding a piece of ice at Delaware River
Northeast Region Photo Contest Winner | March 2019 | People
Jonathan Cohl holding a piece of ice from Delaware River at Frenchtown, NJ
Northeast Region Photo Contest Winner | March 2019 | People
Jonathan Cohl holding a piece of ice from Delaware River at Frenchtown, NJ
Bottom of the Ice Core
Craig Lee holds the ice drill with the end of the first ice core segment exposed. The sample will next be measured, logged, and processed in the field.
Craig Lee holds the ice drill with the end of the first ice core segment exposed. The sample will next be measured, logged, and processed in the field.
Wolverine Glacier Ice
Photo of Wolverine Glacier ice. Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, a "benchmark glacier" in Alaska.
Photo of Wolverine Glacier ice. Wolverine Glacier is in the Kenai Mountains on the coast of south-central Alaska. In 1966 scientists with the USGS began making direct measurements of surface mass balance at Wolverine Glacier, a "benchmark glacier" in Alaska.
Degrading ice wedges, Ikpikpuk River Delta on North Slope of Alaska
Degrading ice wedges on the Ikpikpuk River Delta on the North Slope of Alaska.
Degrading ice wedges on the Ikpikpuk River Delta on the North Slope of Alaska.
Sea ice in the Chukchi Sea, Alaska
Sea ice in the Chukchi Sea in 2013.
Sea ice in the Chukchi Sea in 2013.
Broken Ice
Ice is pushed away from the hull of the Coast Guard Cutter Healy Sept. 1, 2009.
Ice is pushed away from the hull of the Coast Guard Cutter Healy Sept. 1, 2009.
Arctic Sea Ice
Image of sea ice along the Arctic Ocean.