geography exam 4 chapter 18

The Arctic is warming about how many times faster than the rest of the world?

2

What percentage of soils in the Northern Hemisphere are permafrost soils?

25%

Scientists think that northern permafrost could release up to about __________ billion metric tons of carbon to the atmosphere by 2100.

500

During the last glacial maximum, sea levels were __________ meters lower than today.

85

_________ is a large mass of ice that is formed from the accumulation of snow.

A glacier

In late July 2012, what happened on Greenland that had never been witnessed before?

Almost all the surface layer of the ice sheet melted.

What factor do scientists think is causing some of Antarctica's outlet glaciers to flow into the ocean faster?

As ice shelves break apart, their buttressing effects are removed.

_________ occurs where permafrost is 100 meters thick or more.

Continuous permafrost

How does the active layer respond to atmospheric warming?

It deepens.

What happened to the Larsen B ice shelf in 2002 that surprised scientists?

It disintegrated.

_________ are mounded accumulations of glaciofluvial sediments deposited by an ice sheet.

Kames

_________ is ground that has been influenced by freeze-thaw cycles that slowly wedge soil apart.

Patterned ground

What factor do scientists think is causing some of Greenland's outlet glaciers to flow into the ocean faster?

The glaciers are being lubricated by liquid water from moulins.

________ is any debris deposited by a glacier without the influence of running water.

Till

The process in which the movement of one material wears away another material is called _____

abrasion

When the mass balance of a glacier is positive, the toe's position will ______

advance

A(n) __________ is a steep-sided sharp ridge.

arête

The fastest flow in a glacier occurs where?

at the surface and center of the glacier

Proglacial lakes are found where?

at the toe of a glacier

In the __________ zone, ice cracks and breaks and forms crevasses.

brittle

Global sea levels were lower over 10,000 years ago due to what?

building of continental ice sheets

A(n) __________ is a bowl-shaped depression with steep headwalls.

cirque

What type of glacier forms a bowl-shaped depression?

cirque glacier

A low area or pass over a ridge formed by two cirque glaciers is called a(n) ____

col

Which glacial landform is an elongated hill composed of till?

drumlin

When trees become tilted as the active layer deepens during summer, a __________ results.

drunken forest

The elevation at which snowfall accumulation and snowmelt are equal is called the _______

equilibrium line

Which glacial landform is an elongated ridge composed of sorted sand and gravel that was deposited by a subglacial stream?

esker

A drowned glacial valley is called a ________

fjord

What type of glacier forms a large dome over high mountain regions?

ice cap

An __________ is the portion of an ice sheet or an outlet glacier that extends over the ocean.

ice shelf

An __________ is a large block of ice that breaks from the toe of a glacier or an ice shelf and floats in the ocean or a lake.

iceberg

Which is not related to the current loss of ice on Greenland?

increased precipitation

Which is a depression formed by a buried stagnant ice block?

kettle hole

Which type of moraine forms along the edge of a glacier?

lateral moraine

Where two glaciers merge, their lateral moraines also merge, forming a __________ moraine.

medial

Which is not a significant factor causing sea-level rise?

melting ice shelves

What is a heap of unsorted sediments deposited by a glacier called?

moraine

The Northern Hemisphere's thickest permafrost is found in ______

northeastern Russia

When the mass balance of a glacier is neutral, the toe's position will _______

not change

One of a series of small lakes that form in a glacial valley is called a _____

paternoster lake

What type of glacier forms lobes of ice that spill out onto flat plains?

piedmont glacier

A __________ is a hill with a core of ice.

pingo

In the __________ zone, ice deforms and flows in a glacier.

plastic deformation

The process in which a glacier pulls up and breaks off pieces of bedrock as it moves downslope is called __________.

plucking

Atmospheric warming will do what to the elevation of the equilibrium line?

raise it

A __________ moraine forms where the toe of the glacier pauses as it is gradually retreating upslope.

recessional

When the mass balance of a glacier is negative, the toe's position will _________

retreat

What is the name for an elongated and asymmetrical ridge of glacially carved bedrock?

roche moutonnée

Which is not used by scientists to monitor changes in glacier mass balance?

seismometers

Streams that flow beneath a glacier and exit from its toe are called what?

subglacial streams

Unfrozen areas in an area dominated by permafrost are called ______

talik

A lake that forms within or just below a cirque is called a(n) _____

tarn

__________ moraine marks the farthest advance of the glacier's toe before it begins retreating upslope.

terminal

The surface of permafrost that thaws each summer and freezes in fall is called _____

the active layer

The terminus of a glacier is the _______

toe

The __________ zone is found about 60 meters below the glacier's surface.

transition

What type of glacier occupies mountain valleys?

valley glacier

The __________ is the area of a glacier where ice loss exceeds ice accumulation.

zone of ablation

The __________ is the area of a glacier where ice gain from snowfall exceeds ice loss.

zone of accumulation