Geology Chapter 14
Which of the following control the Milankovitch cycles that influence global climate?
Eccentricity (the varying shape of Earth's orbit) Precession (the wobble of Earth's rotational axis) Varying tilt angles of Earth
If global sea levels rise, what could happen to West Antarctica?
More of the ice sheet could float and detach; collapsed parts would melt and raise sea level more.
Which of the following are true regarding the location of ice sheets and glaciers?
Most glaciers are in high latitudes or high elevations. The largest ice mass is on Antarctica. The second-largest ice mass is on Greenland.
Ice Sheet/Continental Glacier
glacial mass spreading outward from a continental accumulation zone.
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
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) ______. Multiple choice question.
ice age
sea ice
ice formed by the freezing of the surface of the sea
Ice shelf collapse and causes
increased temperature (surface meltwater fracturing) and basal melting from increased ocean temperatures
Coasts that form where the land has been inundated by the sea due to a relative rise in sea level are ______ coasts; ones that form where the land experiences a relative drop in sea level are ______ coasts. Multiple choice question.
submergent;emergent
What is a fjord, and where are they found?
long narrow steep sloped inlets - norway and netherlands
Glacial grooves and striations
long parallel scratches formed by sediment embedded in a glacier that has passed over the surface
Zone of ablation (glacier)
the area in the lower part of a glacier where there is a net removal of glacial ice year after year
Rapid increases and decreases in global sea level are related to ____________________.
the extent of continental ice sheets.
equilibrium line
the place on a glacier where snow accumulation and melting are in balance
What is sublimation?
the process in which a solid changes directly into a gas
glacial drift
the rock material carried and deposited by glaciers
Glaciers move, or _________ sediment of all sizes within, on top of, and underneath the moving ice.
transport, carry
Sediment that is transported ______ a glacier is most likely to be ground to a very fine powder called rock flour. Multiple choice question.
underneath
glacial till
unsorted glacial sediment
glacial meltwater
water that flows out from the front (downhill) edge of a melting glacier
zone of accumulation (glacier)
where additions in ice exceed losses
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 sheet recede, sea levels __________.
rise
A glacier__________.
can cover a continent may be restricted to a single valley is a moving mass of ice
Sea-level fall may expose the following features along a coastline.
- Coral reefs - Wave-cut platform - Wave-cut notch
What evidence exists for past glaciation and a colder climate in the United States?
- Outcrops that display glacial scratches and polish - Pollen records that show a change from colder to warmer climate plants - Smoothed-off areas of bedrock - Moraines and other glacial sediment
What approaches have been tried to address shoreline erosion problems?
- Seawalls and breakwaters - Jetties and groins - Not building along coasts - Beach nourishment
What are some hazards that exist along coastlines?
- Wave erosion, especially during storms - Strong winds and rain; flooding - Storm surge
Order the steps of glacier ice formation from snowflakes, beginning with the snowfall. Place the first step at the top and the last step at the bottom.
1. snowflakes fall as individual flakes 2. snowflakes are pressed together; air is forced out 3. snowflakes are compressed into irregular, dense figures 4. snow changes into interlocking crystals and has a bluish color
What is a snowfield?
A large amount of snow that doesn't melt all year.
What is an arete and how is it formed?
An arete is a knife-edge ridge. *Two corries erode back towards each other
submergent coasts
Barrier islands; estuaries; fjords
A block of ice that is floating in a body of water melts completely. What happens to the water level?
It doesn't change
emergent coasts
Marine terraces; wave-cut notches; exposed coral reefs
glaciofluvial deposits
Material moved by glaciers and subsequently sorted and deposited by streams flowing from the melted ice. The deposits are stratified and may occur in the form of outwash plains, deltas, kames, eskers and kame terraces
What is a cirque?
a bowl-shaped hollow eroded by a glacier
alpine glacier
a glacier in mountainous regions that flows down preexisting valleys.
piedmont glacier
a glacier that forms when one or more alpine glaciers emerge from the confining walls of mountain valleys and spread out to create a broad sheet in the lowlands at the base of the mountains.
The ice ages ______.
are so called because over the past two million years, there was a marked increase in glacial periods coincide with the Pleistocene Epoch
Lateral moraines form ______________.
as a glacier passes and drops its till on the side
glacial ice forms________,
as snowflakes are buried and compressed, eventually becoming crystalline ice
Any sediment carried by ice, icebergs, or meltwater is called glacial________.
drift
What is a tarn?
lake in a cirque