Arts

Question 1

2. List 3 ways in which water affects mass-wasting processes? (3 Marks)

Answer 1

 Water destroys particle cohesion by filling pores in sediment (saturation), which triggers mass wasting.  However, when water only partially fills the pore spaces, it actually increases cohesion.  Water also adds mass to the material, and this mass alone may be sufficient to cause gravity to act on a slope.

Question 2

4. List four triggers of mass wasting as discussed in the text? (4 Marks) 

Answer 2

 Saturation of material  Over steepened slopes  Removal of vegetation  Earthquakes

Question 3

11. What are the three main parts (zones) of a river system? 

Answer 3

The zone of sediment production, at the headwaters, where sediment is derived.  The zone of sediment transport, downslope from the headwaters.  The zone of sediment deposition, at and near base level.

Question 4

14. List the three factors that influence flow velocity. 

Answer 4

 Channel gradient: when steeper, velocity is greater.  Channel size, shape, and roughness influence the friction: greater friction means less velocity and more turbulence. A smooth channel allows more uniform flow.  The discharge is the amount of water flowing in the channel, which is calculated by the velocity multiplied by the cross-sectional area.

Question 5

19. In what three ways does a stream transport its load? Which part of the load moves most slowly?

Answer 5

 As dissolved load within the water,  as suspended load held in the water column,  and as bed load along the streambed.  Bed load moves only intermittently, so it moves slowest

Question 6

List two kinds of floods

Answer 6

Regional floods occur due to heavy rains or rapid snowmelt that causes streams to overtop their banks because the water cannot infiltrate or discharge as fast as the precipitation.
Flash floods occur because of surface conditions that limit or prevent infiltration, heavy rainfall, and topography. They occur with little warning, and unlike regional floods, they cause the water level to rise very rapidly and have very high flow velocities.

Question 7

31. List the three basic flood control strategies

Answer 7

 Artificial levees are built to increase the volume of water a channel can hold, they are higher and steeper than the natural levees that border the channel.  Flood control dams store floodwater and then let it out slowly, which lowers the flood crest by spreading it out over a long time span.  Channelization is the alteration of a stream channel to speed up the flow velocity to prevent water level from reaching flood height.

Question 8

What are two geological roles for groundwater? 

Answer 8

Groundwater is an equalizer of streamflow and an  Agent of erosion.

Question 9

Define Stalagmites, and define Sinkholes

Answer 9

51. Stalagmites form on the cavern floor when water falls from the cavern ceiling. The drops deposit calcium, which slowly builds a formation that slowly grows toward the ceiling. 52. Sinkholes can also form when the roof of a cavern collapses under its own weight.

Question 10

Where are glaciers found on Earth today, and what percentage of Earth’s land surface do they cover?

Answer 10

They are found in Earth’s polar regions and high mountain environments.  Glaciers today cover nearly 10 percent of Earth’s surface.

Question 11

Describe how glaciers fit into the hydrologic cycle. What role do they play in the rock cycle?

Answer 11

In the hydrologic cycle, when precipitation falls at high elevations or high latitudes, the water may become part of a glacier, where it can be stored as glacial ice for tens, hundreds, or even thousands of years.  In the rock cycle, the moving mass of ice scours the land surface, acquiring, transporting, and depositing great quantities of sediment.

Question 12

Define an ice shelf.

Answer 12

Ice shelves are large, relatively flat ice masses that float seaward from the coast but remain attached to the land along at least one side.

Question 13

Movement within glacier

Movement of entire glacier

Answer 13

Plastic Flow

Basal Slip

Question 14

What is an ephemeral stream

Answer 14

An ephemeral stream (or wadi, arroyo, donga, or nullah) is dry most of the time. It carries water only seasonally, in response to specific episodes of rainfall, for only a short period of time.

Question 15

What conditions favor the preservation of an organism as a fossil? (2 Marks)

Answer 15

rapid burial and  The possession of hard parts

Question 16

List three examples of trace fossils. (3 Marks)

Answer 16

Tracks—animal footprints made in soft sediment that later became sedimentary rock.  Burrows—tubes in sediment, wood, or rock made by an animal. These holes may later become filled with mineral matter and preserved. Some of the oldest-known fossils are believed to be worm burrows.  Coprolites—fossil dung and stomach contents that can provide useful information pertaining to the size and food habits of organisms.  Gastroliths—highly polished stomach stones that were used in the grinding of food by some extinct reptiles.

Question 17

. List three types of radioactive decay. (3 Marks

Answer 17

Alpha decay  Beta decay  Electron capture

Question 18

22. What are the four basic units that make up the geologic time scale? (4 Marks)

Answer 18

Eons,  eras,  periods, and  epochs

Question 19

Explain the term Hadean. (1 Mark)

Answer 19

Hadean refers to the earliest eon of Earth’s history (before the oldest know rocks)

Question 20

Is the Mesozoic an example of an eon, an era, a period, or an epoch? What about the Jurassic? (2 Marks)

Answer 20

The Mesozoic is an example of an era. The Jurassic is an example of a period

Question 21

List these three magmas in order from the most silica-rich to the least silica-rich composition: basaltic magma, rhyolitic magma, andesitic magma. (3 Marks)

Answer 21

Most silica rich is felsic (rhyolitic),  Then intermediate (andesitic),  Then least silica rich is mafic (basaltic).

Question 22

List the two primary factors that determine the manner in which magma erupts. (2 Marks)

Answer 22

Viscosity and gas content are the two primary factors that determine how magma erupts.

Question 23

Contrast pahoehoe and aa lava flows. (2 Marks)

Answer 23

Aa flows have surfaces of rough jagged blocks with dangerously sharp edges and spiny projections. Pahoehoe flows exhibit smooth surfaces that sometimes resemble the twisted braids of ropes.

Question 24

. Distinguish among conduit, vent, and crater. (3 Marks)

Answer 24

A conduit is a path up which magma travels to the surface. A vent is the surface opening at the top of a conduit. A crater is a bowl-shaped depression at the summit of a volcano.

Question 25

. How is a crater different from a caldera? (2 Marks)

Answer 25

Craters are less than 1 kilometer in diameter;  Calderas are greater than 1 kilometer in diameter.

Question 26

What is a lahar and is it always triggered by volcanos? (2 Marks)

Answer 26

 A lahar is a type of fluid mudflow;  It is not necessarily triggered by a volcano.

Question 27

List three volcanic hazards other than pyroclastic flows and lahars. (3 Marks)

Answer 27

Volcano-related tsunamis;  volcanic ash clogging airplane engines;  toxic volcanic gases affecting respiration;  Volcanic ash in the atmosphere blocking the Sun and triggering sulfuric acid rain.

Question 28

Describe dikes and sills using the appropriate terms from the following list: massive, discordant, tabular, and concordant. (2 Marks

Answer 28

A dike is a tabular, discordant intrusive igneous body. A sill is a tabular, concordant, tabular body.

Question 29

Distinguish among batholiths, stocks, and laccoliths in terms of size. (3 Marks)

Answer 29

Batholiths are the largest of the igneous intrusive bodies—they are massive. Stocks are also massive and are the next largest. Laccoliths are sort of mushroom-cap shaped, generally concordant at their base, discordant at the mushroom cap, and the smallest of these three bodies.

Question 30

. Name two plate tectonic settings in which you would expect magma to be generated. (1 Mark)

Answer 30

Divergent and convergent plate boundaries.