Ch. 14 Geology Review

Steep, exposed slopes

snow and ice slide downhill and are not allowed to pile up

Glacial ice forms as

snowflakes are buried and compressed, eventually becoming crystalline ice

Which of the following are true regarding the location of ice sheets and glaciers?

-second-largest ice mass is in Greenland. -Most glaciers are in high latitudes or high elevations. -The largest ice mass is in Antarctica.

Which of the following control the Milankovitch cycles that influence global climate?

Eccentricity (the varying shape of Earth's orbit) Varying tilt angles of Earth Precession (the wobble of Earth's rotational axis)

Match the feature with its description and how it may indicate the past presence of glaciers. Erratic Dropstone Tillite Polished and scratched bedrock

Erratic It may consist of a huge out-of-place block deposited on a landscape; glaciers transport huge rocks to places where such rock types are not present in the bedrock. Dropstone It consists of a larger stone that is deposited in otherwise fine-grained marine and lake sediment; floating icebergs dropped the stone. Tillite It consists of consolidated till and/or poorly sorted, glacially deposited sediment that has now become a sedimentary rock. Polished and scratched bedrock It consists of bedrock that has been smoothed and grooved; glacially carried sediment erodes away at the bedrock below.

A moving mass of ice, which may range in size from a huge ice sheet that covers large regions to a smaller mass that is restricted to a single mountain or valley, is called a(n)

Glacier

What are some characteristics of glaciers and glacial areas?

Glaciers form where snow and ice accumulate faster than they melt. Glaciers flow. Glaciers may fracture, forming crevasses.

What are some characteristics of glaciers and glacial areas?

Glaciers form where snow and ice accumulate faster than they melt. Glaciers may fracture, forming crevasses. Glaciers flow.

Alpine glaciers

Glaciers that begin in mountainous terrain and flow down valleys

What area of the Northern Hemisphere, covered by ice 28,000 years ago, is also ice covered today?

Greenland

Which of the following are common processes that may affect shorelines?

Movement of waves and tides Fine sediment carried by wind Transport of sediment by rivers Deep- and shallow-water currents

Which of the following best describes the composition of the atmosphere and the amount of energy given off by the Sun, both of which affect Earth's global climate? A. Neither one is constant over time. B. The Sun's energy is constant, but atmospheric composition is not constant. C. Both are constant over time. D. The Sun's energy is not constant, but atmospheric composition is constant.

Neither one is constant over time.

A glacier that is calving is....

collapsing at the front, and large blocks of ice are breaking off

A time when glaciers are more widespread is called a(n) ______ period; a time when glaciers are melting and retreating is called a(n) ______ period.

glacial; interglacial

A period of time in which large regions of land are covered year-round with ice and snow, especially in the last 2 million years, is called a(n) ______.

ice age

Rapid increases and decreases in global sea level are related to ______.

the extent of continental ice sheets

Most of the sediment that glaciers carry comes from

the slopes that flank the glacier and the bedrock below the glacier

Most of the sediment that glaciers carry comes from ______.

the slopes that flank the glacier and the bedrock below the glacier

grooves and streaks

these are created as sediment trapped in the glacier is being carried by the flow

Sediment that is transported ______ a glacier is most likely to be ground to a very fine powder called rock flour.

underneath

The movement of a glacier through an area ______.

wears down topographic highs locally polishes smooth surfaces onto bedrock may carve grooves and scratch marks into bedrock

Piedmont glaciers

occur when steep valley glaciers spill into relatively flat plains, where they spread out into bulb-like lobes

blue ice

occurs when snow falls on a glacier & is compressed & becomes part of glacier that winds its way toward a body of water

Rivers and streams flowing away from glaciers deposit ______.

outwash plains

A condition in which water in the uppermost part of the ground remains frozen all or most of the time is....

permafrost

When continental ice sheets recede, sea levels

rise

Order the steps of glacier ice formation from snowflakes, beginning with the snowfall.

1. Snow Falls 2. Snowflakes are pressed together, forcing air out. 3. Snowflakes are compressed into irregular, dense spheres. 4. Snow changes into interlocking crystals and gets a blue color.

They rate at which glaciers move varies widely, from a few centimeters a day to over ______ per day. 10 meters 30 meters 100 meters

30 meters

What is permafrost?

A condition in which water in the uppermost part of the soil profile is permanently frozen

Match the locations on the image with descriptions of glaciers present there. Instructions A B C D E

A- Antarctica: it is the largest ice mass on Earth and has mostly ice sheets with some valley glaciers. B- Andes (especially Patagonia): glaciers occupy high peaks, mostly in the southern part of the mountain range. C- North America: glaciers are present mainly in the higher peaks in the west. D- Greenland: large ice sheets and smaller glaciers occupy 80% of this landmass. E- Tibetan Plateau and the Himalaya: glaciers cover many of the highest parts of this area.

Match the lettered area indicated on the image to the correct feature.

A-Cirque B-Tarn C-Hanging valley D-Arête

Which four factors are considered significant in causing the ice ages?

Changes in solar activity Position of the continents Amount of CO2 and methane in the atmosphere Changes in Earth's tilt and orbit around the Sun

Match the glacial features with their descriptions. Eskers Kettle lake Glacial outwash Recessional moraine Till Drumlins

Eskers- Long, sinuous ridges deposited by a meltwater stream beneath a glacier as it retreats Kettle lake- Formed as a block of ice left behind by a glacier melt, leaving a depression that fills with water Glacial outwash River-carried sediment that may either be deposited near to or distant from a retreating glacier Recessional moraine- Forms as the front of a glacier melts back and stagnates for some period of time in one location, depositing a pile of sediment Till- The general name given to deposited glacial sediment Drumlins- Streamlined hills formed as a moving glacier sculpts material into this shape

Match the names of lakes that existed in glacial times with the features that remain today. Lake Bonneville Lake Missoula Lake Lahontan

Lake Bonneville- Great Salt Lake; salt flats of the same name as the original lake Lake Missoula- Channeled Scablands Lake Lahontan - Smaller lakes in the low basins of western Nevada

Ice sheets

Large, regionally continuous masses of ice more than 50,000 km2 in area

What evidence exists for past glaciation and a colder climate in the United States?

Moraines and other glacial sediment Outcrops that display glacial scratches and polish Pollen records that show a change from colder to warmer climate plants Smoothed-off areas of bedrock

The largest accumulations of ice are in glaciers we call ice _______ . Glaciers that flow down valleys in mountainous regions are ________ , cirque, or valley glaciers. When either of these two glacial types spread out in less confined topography, they are ________ glaciers.

Sheets Alpine Piedmont

Which of the following statements are true regarding the sediment glaciers carry?

Some sediment is brought to glaciers by streams. Sediment is largely unsorted and angular. Sediment that is carried and deposited by a glacier is a moraine. The sides and base of glaciers have the most abundant sediment.

Which of the following statements are true regarding the sediment glaciers carry?

Some sediment is brought to glaciers by streams. The sides and base of glaciers have the most abundant sediment. Sediment is largely unsorted and angular. Sediment that is carried and deposited by a glacier is a moraine.

The remnant of the much larger glacial Lake Bonneville is the Lake________.

The Great Salt Lake

How does a glacier, at its base and sides, modify a bedrock valley?

The rock beneath may be smoothed, polished, and scratched. Sediment is left behind on the sides and bottom of the valley. Rocks carried by glaciers grind and scrape the rock surface.

Which of the following pieces of evidence, supporting past glaciations in the United States, are visible in this image?

There are ridges that represent piles of glacial sediment (mostly moraines); these were deposited by the retreat of glaciers. There are smooth troughs that trend from northeast to southwest; these were smoothed off by movement of ice sheets.

Crevasses

These are fractures in a glacier, formed as internal stresses cause its upper surface to break.

Rock Powder

This is created as glacial movement grinds up pieces of surrounding rock.

Indicative of the carving and eroding of the original V-shaped river valley, glaciers create _________-shaped valleys.

U Shaped

What landforms would you expect to see in the diagram after the glaciers melt completely away?

U-shaped valleys Narrow, sharp ridges High, sharp peaks

The ice ages________ A) are so called because over the past two million years, there was a marked increase in glacial periods B) experienced more ice at the equator than at other times in Earth's past C)coincide with the Pleistocene Epoch D)indicate that glaciers are now made of mostly ice and before they were made mostly of snow

are so called because over the past two million years, there was a marked increase in glacial periods coincide with the Pleistocene Epoch

Glaciers move

at highly variable rates (some move at centimeters per day while some at meters per day)

Large blocks of ice collapsing off the front of a glacier are said to be ______.

calving

Any sediment carried by ice, icebergs, or meltwater is called glacial

drift

The area on a glacier where the accumulation of ice and snow exactly balances the loss is called the _________ line

equilibrium

On a glacier, the area where the accumulation of ice and snow exactly balances the loss is called the ______

equilibrium line

The time during an ice age that occurs between glacial periods, when glaciers are melting and retreating, is called a(n) period.

interglacial

A glacier ______.

is a moving mass of ice may be restricted to a single valley can cover a continent