Chapter 12-15
Approximately what percentage of Earth's surface is exposed above sea level?
29%
The oceanic crust thickness is about ____ km, and the average continental crust thickness is ____ km.
5; 30
Four Earth's continental shields
African, Canadian, Australian, and Brazilian
Since the core's mass is about one third of Earth's entire mass, the volume of the core is also of one third of the Earth's entire volume.
False
The density of material below the Moho is less than that above it.
False
The moment magnitude scale is based on energy released and is less accurate than Richter's scale which is based on the amplitude of seismic waves
False
The oceanic crust is less dense than the continental crust.
False
The principle of buoyancy and balance, when applied to Earth's crust, helps us to explain fluctuations in Earth's outer crust, a properly known as
Isostatic adjustment
Which of the following is true of the asthenosphere?
It contains pockets of increased heat, it flows, and it carries the lithospheric plates
Which of the following is not an example of an age-relationship based on absolute dating?
The Coconino formation in the Grand Canyon is older than the Kaibab formation
Which of the following statements about Earth's core is not true?
The inner core is believed to be liquid and the outer core solid
Which of the following is true of the earthquake in the Liaoning Province of NE China on February 4, 1975?
The quake was successfully forecasted and 3 million people were evacuated
A hypsographic curve is a graph that shows the Earth's surface by area and elevation in relation to sea level
True
A residual "synclinal ridge" may form within a trough of a fold
True
A slope is stable is its strength exceeds the weathering and erosion process
True
Depth of earthquake focus increases with increasing distance from ocean trench
True
Earth was once in a molten state, during which materials became sorted based on density.
True
Ocean floor subducts under continents because the ocean floor is denser than continental material
True
Orogeny means mountain generating
True
The Hawaiian Islands were formed as a result of a rising plume of magma from the mantle
True
The Moho mirrors the surface topography, i.e., high places on the surface of the Earth overlies areas in which the Moho descends to greater depths, and vice versa.
True
The age of the sea floor increases with increasing distance from a mid-ocean ridge
True
The fluid outer core generates 90% of Earth's magnetic field.
True
The magnetic stripes found around mid-Atlantic ridge were due to the magnetic reversal
True
The mean sea level is at 0m
True
Uniformitarianism assumes that the same physical processes we see today are a key to understand the processes that have been operating throughout the geologic time.
True
The dynamic equilibrium model refers to
a balancing act between tectonic uplift and rates of denudation by weathering and erosion in a given landscape
Movement at the geomorphic threshold signals
a conversion of potential energy to kinetic energy
The two types of time
absolute and relative
After a threshold is crossed, the landscape
adjusts to a new equilibrium condition
At which of the following locations does subduction occur?
along collision zones between continental and oceanic plates
Folded layers of rock can form a wavelike pattern of troughs and crests. The layers near the crest form
an anticline
Which of the following is an example of a first order of relief?
an ocean basin
Four evidences Wegener used to prove his hypothesis
coastal lines, rock types, mountain types, and ancient climates
Convergent plates boundaries are characteristics of
collision zones between plates
In 1912, German geophysicist and meteorologist, Alfred Wegener first proposed the ______ hypothesis about the Earth's land mass migration.
continental drift
Four volcanic activity zones
continental rift valley, oceanic-continental plate, sea-floor spreading, and hot spots
A _____, or heartland region, is an old and stable part of the continental crust.
craton
Which of the following gives the correct sequence of layers in the Earth, from the surface to the center?
crust, asthenosphere, lower mantle, core
All processes that cause reduction and rearrangement of landforms are included in the term of
denudation
Which of the following lists the correct sequence of divisions in the geologic time scale, from largest to smallest?
eon, era, period, epoch
The area at the surface directly above the subsurface location where seismic waves are initiated is termed the
epicenter
When rock strata are strained beyond their ability to remain an intact unit, displacement occurs in a process known as
faulting
The motion of seismic waves is initiated in a subsurface area along the fault plane called the
focus, or hypocenter
The form that a landscape exhibits results from a balance between
forces acting on the landscape, endogenic and exogenic processes, inputs and outputs of matter and energy
On which part of a slope would rocks tend to fall at the highest speed
free face
Compared to oceanic crust, continental crust is
generally more complex on content and structure
_____ threshold is the point at which there is enough energy to overcome resistance against movements
geomorphic
The science that specifically studies the origin, evolution, form, and spatial distribution of landforms is
geomorphology
Which of the following plays a role in the shaping of Earth's surface?
gravity, the action of wind water ice, and the radioactive decay of atoms
The decay rate is expressed as ____, the time required for one half of the unstable atoms in a sample to decay into "daughter" isotopes.
half-life
Chemical weathering is greatest under conditions of
higher mean annual rainfall and temperature
The youngest epoch in the geologic time scale is
holocene
In which climates would rock be weathered to the greatest depth?
hot and wet
Volcanic activity located away from plate boundaries is associated with
hot spots
The transportation and deposition of materials by media powered by solar energy is the
hydrologic cycle
The geologic cycle is composed of three subsystems:______, ______, and ______.
hydrologic, rock, tectonic
Three basic rock types
igneous, sedimentary, metamorphic
Knowledge of Earth's interior is derived from
indirect evidence involving the analysis of seismic waves
The Earth's dominant materials are ____ and ____.
iron and silica
Earth's magnetic field
is variable, and it has phased to zero some nine times during the past 4 million years
In most areas, the upper surface of bedrock is partially weathered to broken-up rock called
regolith
Vertical elevation differences in a local landscape are referred to as
relief
Two types of scale to rate earthquakes _____ and _____.
richter scale; movement magnitude scale
Several large, linear lakes are formed in East Africa. This is evidence of what process?
rifting
Divergent plate boundaries are characteristics of
sea-flooring spreading centers
An instrument used to record vibrations in the crust is the
seismograph
Which of the following is incorrectly matched?
shearing-stretching
A continental _____ is a region with a craton is exposed at the surface.
shield
If you were paranoid of earthquakes, which of the following area would be the safest to live?
shield
The San Andreas system in California is an example of a
strike-slip fault, transform fault, right-lateral motions
When geologists or archaeologists dig downward into a unit of rock or sediment, they are digging "back in time". This fact is based on the principle of
superposition
The combination effects of _____ (powered by internal energy) and _____ (powered by the sun through motion of air, water and ice) create Earth's continental crust.
tectonic activity; weathering and erosion
Heat energy and new materials are brought to the surface from the interior by the
tectonic cycle
Rocks are subjected to stress due to _____
tectonic forces, gravity, and pressure from overlaying rocks
Normal faults are associated with
tension forces
Three types of stress
tension, compression, shear
The rate at which rocks weather depends on
the climate of an area, the type of rock, the amount of vegetation
The most detailed order of relief applies to _____ order relief features.
third
Three types of plate boundaries
transform, divergent, convergent
Which of the following is an endogenic process?
volcanism
Which of the following are located along the mid-ocean ridge?
volcanoes
Other than the rock itself, the most important chemical substance needed for the majority of weathering processes is
water
The disintegration and dissolving of surface and subsurface rock is called
weathering
Which of the following is an exogenic process?
weathering
The most active tectonic regions of North and South America are on the
western coasts
Radioactivity dating only can be used to measure relative time
False
Physical weathering dominates in warm and wet climates
False
Which of the following is true of joints?
joints enable more water to move through the ground, joints enhance the rate of weathering
Which layer of planet forms 80% of Earth's total volume, and has an average density of 4.5 g/cm^3?
mantle
Which of the following gives the correct sequence of layers in the mantle, from bottom to top?
mantle, upper mantle, asthenosphere
People often say that California is going to "fall into the ocean". This idea is totally wrong because the San Andreas fault would have to be a _____ fault associated with _____ forces for this to happen.
normal; tension
Three types of orogenesis
oceanic-oceanic collision, ocean-continental collision, continental-continental collision
In reality, a landscape behaves as a(an) _____ system
open
Two most abundant chemical elements in Earth's crust
oxygen and silicon
Wegener used ______ to name a supercontinent approximately 225 million years ago.
pangea
When rock is broken and disintegrated without dissolving, the process in operation is
physical weathering
The asthenosphere can be described as
plastic-like
Uplift of the landscapes creates _____ energy which is converted to _____ energy when materials begin to move downslope
potential; kinetic
Which of the following is incorrectly matched?
radioactive decay heat-exogenic energy source
