Chapter 2 Flashcards
Which source of energy fuels earthquakes and volcanoes?
- Earth’s internal energy
Our Solar System was born about 4.6 billion years ago from an interstellar cloud. Put the stages in which the solar system formed in order below, with the first stage at the top and the final at the bottom
- 1) a rotating spherical cloud is made up of gas, ice, dust, and other solid debris
- 2) matter is drawn inward, the speed of rotation increases, and the mass flattens in a disk
- 3) matter accumulates in the center, building the sun
- 4) particles collide, forming larger bodies that become the planets
It is widely believed that the solar system formed through _____.
- collisions of matter within a rotation cloud of gas and dust
Hydrogen and helium are both _____ elements.
- lightweight
Convergent
- plates move towards each other
Divergent
- plates move away from each other
Transform
- plates slide horizontally past each other
The _____, which is composed of the crush and the uppermost mantle, is the rigid, outermost portion of the Earth.
- lithosphere
The ____ is a thick layer of dense rock that comprises 83% of the Earth’s volume and 67% of its mass.
- mantle
The four inner planets are ______.
- Mars, Mercury, Earth, Venus
A failed rift can occur when _____.
- a rift fails to open enough to form a spreading center
In a subduction zone, the less-dense, most buoyant tectonic plate is called the _______.
- overriding
The following are types of tectonic environments
- transform plate boundaries
- divergent zones
- convergent zones
Which of these Earth’s layers has the lowest density?
- crust
What is the name of the outer, low-density layer of Earth, rich in silicon and oxygen?
- crust
The Earth’s core, which is composed mostly of iron, is divided into the _____ inner core and the _____ outer core.
- solid, liquid
The lithosphere, asthenosphere, mesosphere, outercore, and innercore are layers of the Earth that are distinguished from one another by their _____.
- strengths
___ ____ is the study of movements and interactions of the plates.
- plate techtonics
Taken from the Greek word meaning ‘to build’, the term ____ describes the building of topography and the deformation and movement within Earth’s outer layers.
- techtonics
Which bathymetric feature is formed at spreading centres?
- mid-ocean ridge
Which of these features of the Earth are likely the result of widespread melting during the formation of the Earth’s core?
- the crust, which is made of low-density rocks
- a dense atmosphere
- large oceans
What is the magnitude of the largest earthquake ever recorded?
- 9.5
Which of the following are sources of heat generated during the formation of Earth?
- gravitational energy
- impact energy
- radioactive decay
The hot material rising to the Earth’s surface at hot spots originates from deep in the ___.
- mesosphere
The Earth in its infancy probably grew from _____ that formed a more or less homogeneous mixture of materials.
- random collisions of debris
The movement of molten iron inward to form the Earth’s core resulted in ____.
- the release of gravitational energy, which converted to heat.
The concept of _____ explains how mountain ranges float on the denser mantle.
- isostacy
The four outer planets of the solar system are mostly composed of
- hydrogen, helium, and other frozen materials
In which direction is the Pacific plate currently moving?
- North-west
When does subduction occur?
- when a dense lithosphere plate descends beneath a less dense lithosphere plate.
______ is when heat is transferred as electromagnetic waves.
- radiation
The creation of new oceanic lithosphere at an oceanic ridge and its movement away from the ridge is known as ____.
- seafloor spreading
What is subduction?
- the sinking of a dense lithospheric plate under a less–dense lithospheric plate.
What is the magnetic polarity of lava which cooled 1.5 Ma ago?
- reverse polarity
The core, mantle, and crust are layers of the Earth that are distinguished from one another by their different ____.
- densities
The sun’s energy comes from ____.
- the fusion of hydrogen to form helium
Where is the San Andreas fault located?
- At the boundary between the Pacific and North American plates.
The outer layers of the Earth were active in the process of plate techtonics by ____ billion years ago.
- 2.5
Why does the age of ocean basins not exceed approximately 200 Ma?
- the oceanic crust is constantly being recycled by plate techtonics
Across which parts of the world did Wegener match fossils in order to support his theory of continental drift?
- South America, Africa, Antartica, India, Australia
Earth appears to have begun as an aggregating mass of particles and gases about ____ years ago.
- 4.6 billion
What is the orientation of magnetization patterns on the seafloors?
- magnetic stripes are parallel to mid-ocean ridges
The Hudson Bay area is currently experiencing isostatic adjustment following _____.
- the removal of the ice sheets at the end of the last ice age.
What will happen if rifting continues along the East African rift system?
- the African and Somali plates will be separated by a new ocean.
Why are the Himalayas rising a few millimeters per year?
- India is colliding against the Eurasian plate and both plates have the same density which prevents subduction from happening.
The _____ formed through collisions of particles that accreted together, forming larger objects.
- planets
What corresponds to the outline of the plate boundaries?
- the location of earthquake epicenters
Which bathymetric feature is formed when an oceanic plate is subducting?
- oceanic trench
asteroids
- small, rocky bodies that orbit the sun
asthenosphere
- the layer of the Earth below the lithosphere in which isostatic adjustments take place. The rocks here deform readily and flow slowly.
atmosphere
- the gaseous envelope around the Earth, composed chiefly of nitrogen and oxygen. The average atmospheric pressure at sea level is 101.3 kPa.
bathymetry
- the mapping of depths of water in oceans, rivers, and lakes; the underground equivalent of topography.
brittle
- property of material in which stress causes abrupt fracture.
chondrules
- small, glassy spheres crystallized in space from semi-molten or molten droplets of rock.
comets
- icy bodies moving through outer space.
compression
- a state of stress that causes a pushing together or contraction.
conduction
- a process of heat transfer through collisions between particles. Hot, rapidly vibrating particles transfer kinetic energy to neighbouring colder, slow-moving particles.
continetnts
- lower-density masses of rock, exposed as about 40% of the Earth’s surface: 29% as land and 11% as the floor of shallow seas.
convection
- a process of heat transfer through movement of a fluid; for example, air or water.
convergent zones
- linear areas where plates collide and move closer together. There are zones of earthquakes, volcanoes, mountain ranges, and deep-ocean trenches.
core
- the central zone of the Earth about 2900km below the surface. The core is made mostly of iron and nickel, and exists as a solid inner zone surrounded by a liquid outer shell. The Earth’s magnetic field originates within the core.
crust
- the outermost layer of the lithosphere, composed of relatively low-density materials. The continental crust has lower density than the oceanic crust.
curie point
- the temperature above which a material will not be magnetic.
divergent zones
- linear zones formed where plates pull apart; for example, spreading centers.
ductile
- behaviour of material where stress causes permanent flow or strain.
elastic
- behaviour of material where stress causes deformation that is recoverable; when stress stops, the material returns to its original state.
elements
- distinct varieties of matter; atoms are the smallest particles of elements.
epicentre
- the point on the surface of Earth directly above the fault that moved to generate an earthquake (i.e. the point directly above the hypocentre)
erosion
- the processes that loosen, dissolve, and wear away earth materials. Active agents include gravity, streams, glaciers, winds, and ocean waves.
failed rifts
- spreading centres that did not open wide enough to create ocean basins.
faults
- fractures in rocks where the two sides move relative to each other.
force
- mass times excelleration
glaciers
- large masses of ice that flow down slope or outward
Gondwanaland
- a southern super-continent that included South America, Africa, Antarctica, Australia, New Zealand, and India from about 18 to 75 million years ago.
gravity
- the attraction between bodies of matter
heat
- the capacity to raise the temperature of a mass, expressed in joules.
hot spots
- places on earth where plumes of magma have risen upward from deep in the mantle and through plates to reach the surface.
hydrologic cycle
- the solar-powered cycle where water is evaporated from the oceans, dropped on the land, as rain and snow, and pulled by gravity back to the oceans as glaciers, streams, and groundwater.
hypocente
- the initial portion of a fault that moved to generate an earthquake. Hypocenters are below the ground surface; epicentres are projected above them on the surface.
island arc
- a curved linear belt of volcanoes above an oceanic-oceanic subduction zone; for example, Japan.
isostasy
- the condition of equilibrium wherein the Earth’s crust floats upward or downward as loads are removed or added.
isotopes
- any of two more more forms of the same element. The number of protons is fixed for nay element, but the umber of neutrons in the nucleus can vary, thus producing isotopes.
Laurasia
- a northern super continent that included most of North America, Greenland, Europe, and Asia (excluding India) from about 18-75 million years ago.
lithosphere
- the outer rigid shell of the earth that lies above the asthenosphere and below the atmosphere and hydrosphere.
magnetic field
- a region where magnetic forces affect any magnetized bodies or electric currents. Earth is surrounded by a magnetic field.
magnetic pole
- either of two regions - the north and south poles - where the lines of force of the magnetic field are perpendicular to the earths surface. Magnetic poles do not coincide with geographic poles but are in their vicinity
mantle
- the largest zone of the Earth comprising 83% by volume and 67% by mass.
mesosphere
- the mantle from the base of the asthenosphere to the top of the core.
meterorites
- stony or iron-rich space objects that passed through the atmosphere and landed on the surface of the earth.
nuclear fission
- splitting the nucleus of an atom with resultant release of energy.
nuclear fusion
- combining of smaller atoms to make larger atoms with a resultant release of energy.
Pangaea
- a super continent that existed during late paleozoic time when all the continents were unified into a single landmass.
plastic
- the behaviour of a material that flows as a fluid (liquid) over time, but is strong (solid) at a moment in time.
plate techtonics
- the description of the movement of plates and the effects caused by plate formation, collision, subduction, and slide past.
plates
- pieces of lithosphere that move atop the asthenosphere. There are a dozen large plates and many smaller ones.
plumes
- upwellings of magma rising from deep in the mantle.
radiation
- a process of heat transfer where energy is emitted as electromagnetic waves
radioactive elements
- unstable elements containing excess subatomic particles that are emitted to achieve smaller, more stable atoms.
ridges
- long and narrow volcanic mountain ranges
rift
- the valley created at a pull-apart zone
seafloor spreading
- the movement of two oceanic plates away from each other resulting in magma welling up and solidifying to create new ocean floor.
sediments
- fragments of material of either inorganic or organic origin. Sizes are gravel, sand, silt, and clay. (mixture of silt and clay forms mud)
shear stress
- a state of stress that causes internal planes within a body to move parallel to each other.
solar radiation
- the energy emitted from the sun mostly in the infrared visible light, and ultraviolent wavelengths.
spreading centres
- sites where plates pull apart and magma flows upward to fill the gaps and then solidifies as new ocean fools.
strain
- a change in form or size of a body due to external forces.
stress
- force per area; forces include shear, tension, and compression.
subduction
- the process of one lithospheric plate descending beneath another one.
techtonic cycle
- describes how new lithospheric forms at oceanic volcanic ridges, how lithospheric plates spread apart to open ocean basins, and how the oceanic plates are ultimately reabsorbed into the mantle at subduction zones.
tension
- a state of stress that tends to pull the body apart.
topography
- the mapping of the shape of the surface of the Earth; the land equivalent of bathymetry.
transform faults
- strike-slip faults that connect the ends of two offset spreading centres.
trenches
- the elongate and narrow troughs where ocean water can be more than twice as deep as usual. Trenches mark the down going edges of subduction plates.
triple junction
- a place where three plate edges meet
viscous
- resistant to flowing. The more viscous a substance, the less readily it flows.
volcanoes
- openings of the Earth’s surface where magma has poured or blown forth, typically creating hills or mountains.
