Day 4 Terms (Glaciers)

Glacier

a larger mass of compacted snow and ice \n that moves under the force of its own \n gravity

Where do Glaciers form

• Areas ALWAYS covered by snow \n • Can form at any latitude as long as \n elevation is high enough

Snow Line

lowest elevation at which the \n layer of permanent snow occurs in \n summer

List the stages of a glacier

Snow, Granular Ice, Firn, Glacial Ice

valley (alpine)

forms in valleys of mountains, smaller

continental

Polar regions, thousands of meters thick, \n Greenland and Antarctica, circular or oval in \n shape, breaks off and sea into an iceberg

Describe Glacial Movement

Constantly Moving, Friction from bedrock slows movement, increasing speed of top and middle

Basal slip

friction between glacier and ground \n melts ice, reduces friction, allows glacier to move \n due to gravity, only at base

Plastic flow

crystals deform continuously allowing \n them to slide past one another

Till

unsorted, unstratified material left by a \n glacier

Moraine

deposit of till

Outwash

material deposited by glacial \n melt water- sorted and stratified

Moraines

deposits of till

Drumlins

long, smooth, canoe-shaped \n hills found in groups

What is this?

Fjord

Outwash plains

broad flat areas in front of a \n glacier

Eskers

winding ridges of sediment created by \n deposition of a stream running through a \n glacier

Kettles

bowl shaped hallows in moraines \n and outwash plains, formed where a block of ice has been buried

Lakes

moraine dammed, kettle lakes, \n Cirque lakes

Dust storm

a storm with strong, steady \n winds that lift clay and silt from the top soil

Deflation

removal of loose rock particles \n by wind

Blowouts

holes caused by deflation

Abrasion

wearing away of rock material by \n grinding action

Ventifact

a rock with surfaces that have been \n abraded by wind

Loess

Windblown silt deposits, usually yellow & angular particles

Sand dunes

hills of sand deposited by \n winds

Clastic

Formed from fragments of other \n rocks (sediment)

Chemical

Form when minerals \n precipitate (fall out) of solution

Organic

Forms from sediments \n consisting of the remains of plants and \n animals

Describe a Clastic Sedimentary Rock

Large to small sediment size, eroded and deposited by water

Cementation

the binding of loose \n sediment by minerals filling the space \n between grains

Conglomerate

rounded coarse sand \n and pebbles are cemented together

Breccia

similar to conglomerate, but \n particles are angular

Sandstone

sand is cemented

Shale

made of clay- often breaks in \n sheets

Limestone

can be any color, fine \n grained, calcite (will fizz in acid), formed from shells

Dolostone

similar to limestone, but \n made of dolomite (will not fizz in acid)

Bituminous coal

plant remains

Stratification

arrangement of layers of \n different sediment

Bedding plane

plane between layers, usually \n horizontal, but sometimes cross bedding \n occurs

Fossils

the remains, impression or any other \n evidence of a plant preserved in rock

Ripple marks

sand patterns due to wind, \n wave, stream or current action

Mud cracks

form when mud dries

Nodules

lumps of silica in limestones

Concretion

lump of calcite in shale

Geodes

hallow lumps of silica in \n limestone, often have crystals inside

Weathering

the breakup of rock due to \n exposure to processes that occur at \n Earth’s surface

Mechanical (weathering)

rock is \n broken into smaller pieces

Chemical (weathering)

minerals are \n changed into different substances

Frost wedging

water gets into cracks of \n rocks, freezes (expands) and widens \n cracks

Abrasion

moving sand, pebbles and \n larger rocks scrape against each other

Root wedging

roots grow into cracks widening \n them

Exfoliation

rock is lifted due to tectonic \n activity, releases pressure, causes rock to \n crack

Soil

material made of loose, weathered \n rock and organic material