Chapter 6 Tarbuck Earth Science

define glacier

thick mass of ice formed on land

define valley/alpine glacier

glacier occupying former river valley

define ice sheet

large plain of ice

define ice shelf

flows of glacial ice into ocean that stay connected to mainland

define ice cap

ice sheet but much smaller

define outlet glacier

flow from valley glaciers to produce icebergs

define plastic flow

flow of individual layers inside ice

define basal slip

entire ice mass sliding on ground

where does the glacier move the fastest

middle

define zone of fracture

uppermost part of glacier that can fracture into caves and crevasses

define zone of accumulation

area at top of glacier where snow accumulates and crystallizes

define snowline

line terminating zone of accumulation that shows the lowest point where snow always accumulates

define zone of wastage

zone at bottom of glacier where melting occurs

define plucking

ice sliding along rock picks up rock fragments

define abrasion

glacier grinds rock into rock flour and absorbs it

define glaciated valley

smooth U-shaped valley occupied by a glacier

define cirques

bowl shaped depressions open to main valley

define aretes

ridges formed at the edge of cirques

define horns

peaks formed by aretes converging

define fjords

steep valleys filled with water due to glaciers eroding lower than sea level

define till

ice that melts and released eroded rock

define stratified drift

rocks that are deposited through meltwater streams

define glacial erratics

rocks deposited by glaciers that do not resemble underlying bedrock

define moraine

layer or ridge of till

define lateral moraine

till left on the side of glacial valley

define medial moraine

till left on ground due to two valley glaciers converging

define end moraine

ridge of till that forms when terminus is stationary at the end of glacier

define ground moraine

trail of till left as glacier recedes

define outwash plain

plain of stratified drift

define kettle train

trail of stratified drift

define drumlin

asymmetrical hills of till forming drumlin fields

define esker

stream of deposited sediment that was underneath ice

define kame

hill of deposited sediment that was underneath ice

define proglacial lakes

lakes formed through damming of glaciers

define pluvial lakes

lakes formed in arid regions when temperatures were lower

define dryland

area where annual rainfall is less than annual evaporation potential

define basin and range

landscape type consisting of canyons and basins, located in american west

define bajada

multiple canyon mouths converging forming a mass of alluvial fans

define playa lakes

basins filling with water leaving a lake for only a few days

define inselberg

knobs of bedrock remaining from mountain ranges

define deflation (wind)

lifting and carrying of loose materials

define blowouts

depressions in the ground from wind erosion

define desert pavements

coarse rock surfaces from wind eroding all the fine grains

define loess

wind blown silt that is deposited by dust storms

define dunes

sand in the air that deposits

define slip face

slope of sand dunes

define cross bedding

layered structure of sand dunes

define barchan dunes

crescent shaped dunes, tips point away from wind

define transverse dunes

long ridges separated by troughs perpendicular to wind

define barchanoid dunes

cross between transverse and barchan dunes, scalloped ridges right angled to wind

define longitudinal dunes

dunes forming lines of sand parallel to wind

define parabolic dunes

dunes forming crescent shapes but tips face wind unlike barchan dunes

define star dunes

Ridges and points originating from a point