Background+Research



**1. IMPORTANT TERMS AND DEFINITIONS:**
 * Ablation: ** Ablation refers to all processes by which snow, ice, or water in any form are lost from a glacier.
 * Ablation zone: ** The area of a glacier where mass is lost through melting or evaporation at a greater rate than snow and ice accumulate.
 * Accumulation zone: ** The area of a glacier where mass is increased through snowfall at greater rate than snow and ice is lost through ablation.
 * Arête ** : A sharp-edged ridge of rock formed between adjacent cirque glaciers ** . **
 * Basal sliding: ** The sliding of a glacier over the ground on a layer of water.
 * Cirque: ** A bowl-shaped depression carved out of a mountain by an alpine glacier.
 * Continental glacier: ** A glacier that forms over large areas of continents close to the poles.
 * Crevasse: ** A deep, nearly vertical crack that develops in the upper portion of glacier ice.
 * Erosion: ** The gradual wearing away of Earth surfaces through the action of wind and water.
 * Erratic: ** A large boulder that a glacier deposits on a surface made of different rock.
 * Esker: ** A long, snakelike ridge of sediment deposited by a stream that ran under or within a glacier.
 * Equilibrium line: ** Equilibrium line is the boundary between the accumulation area and the ablation area.
 * Firn: ** The granular ice formed by the recrystallization of snow; also known as névé.
 * Fjord: ** A deep glacial trough submerged with seawater.
 * Glacial drift: ** A general term for all material transported and deposited directly by or from glacial ice.
 * Glacial polish: ** The smooth and shiny surfaces that are produced on rocks underneath a glacier by material carried in the base of that glacier.
 * Glacial surge: ** The rapid forward movement of a glacier.
 * Glacial trough: ** A U-shaped valley carved out of a V-shaped stream valley by the movement of a valley glacier.
 * Glaciation: ** The transformation of the landscape through the action of glaciers.
 * Glacier: ** A large body of ice that formed on land by the compaction and recrystallization of snow, survives year to year, and shows some sign of movement downhill due to gravity.
 * Ground moraine: ** A continuous layer of till deposited beneath a steadily retreating glacier.
 * Hanging valley: ** A shallow glacial trough that leads into the side of a larger, main glacial trough.
 * Horn: ** A high mountain peak that forms when the walls of three or more glacial cirques intersect.
 * Internal flow: ** The movement of ice inside a glacier through the deformation and realignment of ice crystals; also known as creep.
 * Kame: ** A steep-sided, conical mound or hill formed of glacial drift that is created when sediment is washed into a depression on the top surface of a glacier and then deposited on the ground below when the glacier melts away.
 * Kettle: ** A shallow, bowl-shaped depression formed when a large block of glacial ice breaks away from the main glacier and is buried beneath glacial till, then melts. If the depression fills with water, it is known as a kettle lake.
 * Lateral moraine: ** A moraine deposited along the side of a valley glacier.
 * Medial moraine: ** A moraine formed when two adjacent glaciers flow into each other and their lateral moraines are caught in the middle of the joined glacier.
 * Meltwater: ** The water from melted snow or ice.
 * Moraine: ** A general term for a ridge or mound of till deposited by a glacier.
 * Piedmont glacier: ** A valley glacier that flows out of a mountainous area onto a gentle slope or plain and spreads out over the surrounding terrain.
 * Rock flour: ** Fine-grained rock material produced when a glacier abrades or scrapes rock beneath it.
 * Snow line: ** The elevation above which snow can form and remain all year.
 * Striations: ** The long, parallel scratches and grooves produced in rocks underneath a glacier as it moves over them.
 * Tarn: ** A small lake that fills the central depression in a cirque.
 * Terminal moraine: ** A moraine found near the terminus of a glacier; also known as an end moraine.
 * Terminus: ** The leading edge of a glacier; also known as the glacier snout.
 * Till: ** A random mixture of finely crushed rock, sand, pebbles, and boulders deposited by a glacier.
 * Valley glacier: ** An alpine glacier flowing downward through a preexisting stream valley.

**2. EARTH SYSTEM INFORMATION:** The glaciers we will be studying are located in the lithosphere.

**3. FORMATION PROCESS:** Glaciers form where the accumulation of snow exceeds its melting point over many years, often centuries.

**4. FEATURE DESCRIPTION OR CHARACTERISTICS:** Terminus: The front end of a glacier Moraine: A broad term for any mineral ranging from sand to boulders that is deposited by a glacier.

**5. ASTRONAUT IMAGES (2-3) THAT INCLUDE THE FEATURE YOU ARE STUDYING (links, ID#s, or images):** Calvo Glacier: ISS006-E-41461- [] ISS011-E-5575- [] ISS013-E-37810- [] ISS004-E-6823- [] Frias Glacier: ISS018-E-40445- [] ISS013-E-67107- [] ISS004-E-6499- [] ISS004-E-6558- []

**6. GEOGRAPHIC REGION OF FOCUS:** The glaciers we are studying are found on the south-eastern tip of South America. The more specific geographic location of these glaciers is Argentina and Chile.

**7. IF YOU WILL CONDUCT A PLANETARY COMPARISON, PLEASE EXPLAIN:** We will be comparing glacial features on Earth to glacial features on Mars.


 * Keep track of your sources in your bibliography.**