Glacial

Compacted, recrystallized, granular textured snow is know as [blank_start]firn[blank_end]

Ice formed over many years with increased density is known as [blank_start]glacial[blank_end] ice.

Zone of [blank_start]Accumulation[blank_end]: colder, input > output Zone of [blank_start]Ablation[blank_end]: warmer, output > input, loss of snow and ice by melting and evaporation

In regards to glacial movement, velocity is fastest at the

brittle or rigid zone [blank_start]top[blank_end], crevasses plastic zone [blank_start]bottom[blank_end], like melleable plastic

[blank_start]Basal[blank_end] [blank_start]Slip[blank_end] occurs when a high amount of water accumulates at the base of the glacier and can cause surging.

In crevasses, ice stretches on the

In crevasses, ice becomes compressed on the [blank_start]upstream[blank_end] side of an underlying bedrock ridge

[blank_start]Ice Cap[blank_end]: A dome shaped sheet of ice that covers an area less than 50,000km2 in size [blank_start]Ice Field[blank_end]: has a topographically constrained sheet of ice in mountainous areas that frequently has glaciers streaming away from it. [blank_start]Alpine Glacier[blank_end]: A glacier in mountainous regions that flows down preexisting valleys. [blank_start]Cirque[blank_end]: blow shaped area, glacier is confined to the basin [blank_start]Valley Glacier[blank_end]: cirque spill over is river of ice confined with a valley, flows slowly down hill, landscape altered by its erosive passage [blank_start]Piedmont Glacier[blank_end]: if they flow down hill and come to the mouth of the valley and spread out over a flat land [blank_start]Continental Glaciers[blank_end]: on a larger scale > 50,000 km2, continuous mass of unconfined ice is called a continental glacier, often as ice sheet in Greenland and Antarctica.

Weight of ice presses lithosphere down into aesthenosphere, called [blank_start]isostatic[blank_end] [blank_start]depression[blank_end]

Which type of glacier sit atop the island of Greenland?

[blank_start]Glacial Abrasion[blank_end] – scratch and gouge bedrock by ice and rock debris it carries [blank_start]Glacial Striations[blank_end] – caused by glacial abrasion [blank_start]Glacial Grooves[blank_end] – deep striations [blank_start]Glacial Plucking[blank_end] – boulders ripped from bed rock loosened by frost action

During the process of glacier erosion, [blank_start]plucking[blank_end] occurs on the down-ice side of bedrock obstructions, [blank_start]striations[blank_end] on the up-ice side.

During the process of glacier erosion: [blank_start]Cirque[blank_end] – bowl-like feature on mtn flanks [blank_start]Tarn[blank_end] – small lake in bottom of cirque [blank_start]Arête[blank_end] – narrow, steep ridges between cirques [blank_start]Horn[blank_end] – mtn w/3 or more arêtes at summit [blank_start]Glacial Trough[blank_end] – u-shape valley eroded by glacier [blank_start]Hanging Valley[blank_end] – side trough above main trough – possible waterfall

The image shows a [blank_start]cirque[blank_end]

The image shows a [blank_start]horn[blank_end]

The image shows a glacial [blank_start]trough[blank_end]

Smaller alpine glaciers form in bowl-like depressions called what?

a general term for sediments deposited by glaciers: both stratified and unstratified

A general term for sediments directly deposited by glacier – unsorted, unstratified mixture of rock fragments of different sizes from clay to house-sized boulder

Forms of glacial till [blank_start]Basal[blank_end] Till: deposited at the base of the glacier.Intense pressure.Fine grained.Crushed at the bottom. [blank_start]Ablation[blank_end] Till: sediment carried within or on top of ice.

A winding ridge formed by till at the front or side of glacier is known as

Types of Moraines: [blank_start]Lateral[blank_end] – along former edges of glacier [blank_start]Terminal[blank_end] – along front of former glacier [blank_start]Recessional[blank_end] – formed as glacier recedes [blank_start]Medial[blank_end] – between 2 glaciers [blank_start]Ground[blank_end] – irregular deposition as glacier recedes

A previous till streamlined by glacier is known as

A - [blank_start]Terminal[blank_end] moraine B - [blank_start]Recessional[blank_end] moraine C - [blank_start]Terminus[blank_end] moraine D - [blank_start]Lateral[blank_end] moraine E - [blank_start]Medial[blank_end] moraine

Glacial deposional landforms (outwash): [blank_start]Outwash plain[blank_end] - flat feature in front of former glacier (formed by glacial outwash [blank_start]Glacial Outwash[blank_end] – sediments deposited by water out & under a glacier as it melts [blank_start]Kame[blank_end] – large mound deposited near glacier front [blank_start]Esker[blank_end] – winding ridge formed from stream flowing in tunnel through ice under glacier [blank_start]Kettle Lake[blank_end] – big ice block fallen off glacier front is buried by outwash, melts later forming lake

Permafrost: [blank_start]Continuous[blank_end] – poleward of -7ºC mean annual isotherm – all surfaces frozen exp under water – avg 400 m thick, up to 1000 m thick [blank_start]Discontinuous[blank_end] – poleward of -1ºC mean annual isotherm – thinner than continuous, esp. on south facing slopes

A body of unfrozen ground within permafrost, e.g. under a lake, important for movement of groundwater is known as [blank_start]Talik[blank_end]

Soil that melts & refreezes daily or seasonally – as thin as 10 cm in continuous permafrost, up to 2 m thick in discontinuous is known as the [blank_start]active[blank_end] [blank_start]layer[blank_end]

[blank_start]Ground Ice[blank_end] – distinct zones of frozen water within the ground – variable amts of water As these areas freeze & thaw, expand & contract, they cause physical weathering [blank_start]Ice Wedge[blank_end] – water enters crack in active layer [blank_start]Pingo[blank_end] – surface bulges because of ice under pressure below [blank_start]Patterned Ground[blank_end] – land broken into polygons as frost pushes coarser material to surface