"A glacier is a persistent body of dense ice that is constantly moving under its own weight. It forms where the accumulation of snow exceeds its ablation over many years, often centuries. "
Introduction to the formation and movement of glaciers and their impact on landforms over time.
Glacial formation: Understanding how glaciers form and the different types of glaciers, such as valley glaciers and ice caps, is important.
Glacial erosion: Learn about how glaciers erode rock and soil through processes such as plucking and abrasion.
Glacial deposition: When glaciers melt, they leave behind sediment in the form of moraines, outwash plains, and other landforms.
Glacial hydrology: Glaciers are an important source of freshwater, and learning about their role in the hydrologic cycle is important.
Ice dynamics: Understanding how glaciers flow and the factors that affect their movement, such as temperature and slope, is key to understanding their behavior.
Glacial climate feedbacks: Glaciers are sensitive to changes in climate, and studying their interactions with the environment can provide insights into climate change.
Ice core analysis: Analyzing ice cores from glaciers can provide information about past climate conditions and atmospheric composition.
Glaciology tools and techniques: Learn about the tools and techniques used by glaciologists to study glaciers, such as remote sensing and ice-penetrating radar.
Glacial meltwater: Meltwater from glaciers can have significant impacts on downstream ecosystems and human populations, and understanding these effects is important.
Glacial hazards: Glaciers can pose hazards such as glacier floods and icefalls, and learning about these risks is important for safety and management.
Alpine glaciers: These are found in mountainous regions and flow down valleys. They can range in size from small cirque glaciers to large valley glaciers.
Continental glaciers: Also known as ice sheets, these are found in polar regions and cover vast areas. They can be over 10,000 feet thick and can form deep crevasses.
Valley glaciers: These are formed in high mountain valleys and can be narrow or wide. They flow downhill and are often seen as tongues extending down from the mountains.
Piedmont glaciers: These are formed when a valley glacier leaving a mountain range spreads out and covers a wide area. They can form lobes and can be fed by multiple glaciers.
Tidewater glaciers: These are valley glaciers that flow out into the sea. They often calve icebergs and can be found in fjords.
Outlet glaciers: These are formed at the edge of an ice sheet or ice cap and flow out into valleys or the ocean.
Ice caps: These are smaller versions of ice sheets and cover less than 50,000 square kilometers. They are often found on mountain tops and plateaus.
Ice fields: These are flat, relatively level areas covered in ice that may or may not contain glaciers. They are often found in polar regions.
Ice flows: These are slow-moving rivers of ice that can be found on the surface of ice sheets or glaciers.
Ice shelves: These are floating extensions of glaciers or ice sheets that extend out over the ocean. They can be extremely thick and very large.
Firn: This is snow that has been compressed and recrystallized into small grains. It is an intermediate stage between snow and glacier ice.
Glacial ice: This is the hard, dense, and compact ice that forms in glaciers. It can contain bubbles, dust, and other debris that has been trapped as the ice formed.
Blue ice: This is glacial ice that is free of air bubbles and appears blue due to the absorption of longer-wavelength light.
Crevassed ice: This is ice that has been broken and cracked due to stresses in the glacier. It can appear as large crevasses or small cracks in the ice.
Glacier ice caves: These are caves or tunnels that have been formed by melting and flowing water within glaciers. They can be dangerous and unstable environments.
"Although a glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water."
"On Earth, 99% of glacial ice is contained within vast ice sheets (also known as 'continental glaciers') in the polar regions."
"Glaciers may be found in mountain ranges on every continent other than the Australian mainland, including Oceania's high-latitude oceanic island countries such as New Zealand."
"Between latitudes 35°N and 35°S, glaciers occur only in the Himalayas, Andes, and a few high mountains in East Africa, Mexico, New Guinea, and on Zard-Kuh in Iran."
"With more than 7,000 known glaciers, Pakistan has more glacial ice than any other country outside the polar regions."
"Glaciers cover about 10% of Earth's land surface."
"Continental glaciers cover nearly 13 million km2 (5 million sq mi) or about 98% of Antarctica's 13.2 million km2 (5.1 million sq mi)."
"The average thickness of ice in Antarctica's ice sheets is 2,100 m (7,000 ft)."
"The volume of glaciers, not including the ice sheets of Antarctica and Greenland, has been estimated at 170,000 km3."
"Glacial ice is the largest reservoir of fresh water on Earth, holding with ice sheets about 69 percent of the world's freshwater."
"Many glaciers from temperate, alpine, and seasonal polar climates store water as ice during the colder seasons and release it later in the form of meltwater as warmer summer temperatures cause the glacier to melt."
"A glacier acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight."
"As it moves, a glacier abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords."
"A large piece of compressed ice, or a glacier, appears blue, as large quantities of water appear blue. This is because water molecules absorb other colors more efficiently than blue."
"The other reason for the blue color of glaciers is the lack of air bubbles. Air bubbles, which give a white color to ice, are squeezed out by pressure increasing the created ice's density."
"Since glacial mass is affected by long-term climatic changes, e.g., precipitation, mean temperature, and cloud cover, glacial mass changes are considered among the most sensitive indicators of climate change."
"Glacial mass changes are a major source of variations in sea level."
"However, within high-altitude and Antarctic environments, the seasonal temperature difference is often not sufficient to release meltwater."
"Glacier meltwater is a water source that is especially important for plants, animals, and human uses when other sources may be scant."