GEO week 3

Based on map, which of the following plates contain both continental and oceanic crust?

1) Australian plate 2) North American plate 3) South American plate 4) African plate

Best basic ways for scientists to determine Earth's internal structure

1) Observation that meteorites that land on earth are composed of nickel and iron 2) the hypothesis that Earth's magnetic field results from the circulation of metallic ions within the outer core 3) the way seismic waves change velocity as they travel through the interior 4) the discovery that shear waves do not penetrate the outer core, but compression waves do

Paleomagnetism is defined as

1) The study of how rocks containing magnetic minerals retain their orientation on Earth's magnetic field 2) the study of fossil magnetism in rocks

Development of a mid-oceanic ridge system

1) a rising convection cell causes a continental plate to fracture 2) the asthenosphere melts and forms magma 3) tension and silting create a Rift Valley 4) rising magma forms layers of basalt 5) the rift widens and is flooded

Which of the following are examples of the crucial role plate tectonics has played in the evolution of life on Earth?

1) a subduction zone's oceanic trench served as biographical boundary 2) increases in land and area over time created more terrestrial habitat 3) continental drift caused terrestrial life-forms to evolve in isolation 4) life may have originated around volcanic vents on the seafloor

Earth's magnetic field is important because

1) animal migration 2) blocking us from solar radiation (most important) 3) human navigation

Which of the following are ways in which plate tectonics can affect earth's climate over the course of geological time?

1) confidential drift 2) volcanic ash eruptions 3) mountain building 4) ocean circulation

Characteristics of Earth's crust

1) contains silicate minerals 2) contains both basaltic and granitic parts

Examples of convergent plate boundaries

1) continental-continental 2) oceanic-oceanic 3) oceanic-continental

Characteristics of Earth's core

1) has a density GREATER than 10 gm/cm3 2) contains both solid and liquid parts 3) contains nickel 4) contains iron

Evidence Wegener used to support continental drift

1) matching of similar sequences of rocks in Africa and South America 2) jigsaw puzzle fit of South American and Africa 3) matching unique plant and animal fossils in Africa and South America

Based on map, which of the following plates contain only oceanic crust?

1) nazca 2) scotia 3) Jaun de fuca 4) Philippine

Surface features that happen at transform plate boundaries

1) no current or recent volcanism 2) fault valleys with horizontal offset of linear features such as stream channels 3) transform faults offsetting parts of mid-ocean ridged

Surface features that develop at divergent plate biundaries

1) ocean basin with a spreading center in the middle 2) Rift Valley or graben formed by faulting 3) central topographic bulge caused by buckling

Surface features that developed at a convergent plate boundary

1) oceanic trench caused by buckling 2) mountain range containing numerous volcanoes 3) string of andesitic volcanic islands 4) mountain chain of intesnlynfolded and faulted rocks

Characteristics of Earth's oceanic crust

1) overall composition similar to basalt 2) uniform thickness 3) thickness of around 3 miles (5km)

What led to the development of continental drift hypothesis?

1) people suggested as early as the late 1500s that continents had torn away from each other 2) many people noticed the similar outlines of continents on either side of the Atlantic

Characteristics of Earth's mantle

1) susceptible to plastic deformation 2) contains iron-rich silicate minerals 3) has a density LESS than 10 gm/cm3

Which of these represent oceanic-confidential convergent boundaries?

1) the Pacific Northwest 2) the western coast of South America

3 strongest pieces of evidence that Earth's outer core is liquid?

1) the evidence that shear waves are unable to pass through liquids, but compression waves can 2) the discovery that shear waves do not penetrate The core, but compressional waves do 3) the hypothesis that Earth's magnetic field results from the circulation of metallic ions

When two continental plates converge

1) the two land masses crumple and deform 2) subduction stops due to the buoyancy of the continents 3) many earthquakes occur

Characteristics of Earth's continental crust

1) variable thickness 2) overall composition similar to granite 3) thickness as much as 45 miles (70 km)

Characteristics of Earth's asthenosphere

1) weak layer that flows and deforms plastically 2) contains silicate minerals just below their melting point 3) has a density less than 10 gm/cm3

The oldest rocks recovered from the seafloor are about _______ years old

200 million

Which of the following can be used as an illustrative example of slab pull effect?

A blanket sliding completely off a bed when oart of the blanket is left hanging over the size

Which best describes the difference between a fault and a fracture?

A fault is a break in the rock where some movement has taken place, in a fracture no movement has taken place.

The Wallace line in Indonesia separates distinct groups of animals. It's location is marked by

An oceanic trench that did not allow for the creation of land bridges

Due to its influence on Earth's _____, plate tectonics is directly tied to our food and water supplies

Climate

Key factors that determine the elastic limit of rocks and whether they deform brittlely or ductilely to stress are _______. Other factors include temperature, pressure, and time.

Composition and internal structure

The mapping of earthquake epicenters by the world's scientists indicates that earthquakes are ____

Concentrated in zones

Heat transfer driven by temperature-induced changes in the density of material is called ______

Conduction

The uniform pressure that surrounds rocks at depth is ______

Confining pressure

The matching of similar sequences of rocks and fossils and the jigsaw puzzle fit of South America's and Africa's shorelines were WLL used as evidence to support the idea of _____

Continental drift

Plate movement results from ______ cells within the mantle

Convection

Process of ______ and separation of elements and minerals based on density explains Earth's layered structure

Convection

The earth's _______ is characterized by being both solid and liquid and comprised of predominantly iron and nickel

Core

Earth's layers by shallowest to deepest

Crust, mantle, outer core, inner core

When comparing the composition of Earth's crust and deeper interior, silicates are dominant in the _____ and iron is dominant in the _____.

Crust; deeper interior

Name given to the temperature at which a magnetic mineral loses its magnetic properties?

Curie point

Movement in convection cell is ultimately driven by differences in ______

Density

Many scientists believe that life may have originated around seafloor volcanic vents similar to those found at present-day ______ plate boundaries

Divergent

Rift valleys developed at

Divergent boundaries

If enough heat is applied to a solid material, it would change from being brittle to being _____

Ductile

Which observation from paleomagnetic studies of continental rocks made no sense without seafloor spreading and the theory of plate tectonics?

Each of earth's continents exhibited a different polar wandering path

Permanent deformation occurs in rocks when they exceed their _____ limit.

Elastic

Structure, time, pressure, composition, and temperature are

Factors that contribute to the dissimilar materials having different elastic limits and deforming differently

A ______ is a break in the rock along which movement has taken place

Fault

What occurs when rocks are deformed beyond their elastic limits?

Fracture and flow

The change in Earth's temperature wifh depth is known as the _______ gradient

Geothermal

A convection cell is the circular motion of ______ driven by temperature-induced changes in density

Heat and matter

How would you get a material flow instead of fracture when stress is applied to it?

Heat it up

Order in which ideas and evidence for continental drift were developed

In geo pic folder

The African Geeat Rift Valley is in the ______ stages of development as a divergent boundary

Initial

Although the two most abundant elements in Earth's crust are oxygen and silicon, when considering the whole planet, the dominant element composing earth is ______

Iron

Plate tectonics are referred to as a theory because

It provides a comprehensive and unified explanation of how the world operates

Common natural hazards at plate boundaries?

Landslides, volcanic eruptions, and earthquakes

Earth's tectonic plates are equivalent to which of the following layers?

Lithosphere

The Earth's _______ consists of mantle and crystal rocks that are relatively brittle and rigid

Lithosphere

Scientists generally believe that the convective motion of heat and matter in the ______ explains why lithospheric plates are slowly moving on top of the asthenosphere

Mantle

Lithospheric plates are believed to be moving in the same direction as the

Mantle convects

Which of the following are Earth's four major layers shown by seismic studies to be significantly different in composition and physical properties?

Mantle, crust, inner core, and outer core

The mid-Atlantic ridge is the longest ______ chain on Earth

Mountain

Earth's magnetic field is formed by

Movement in Earth's outer core

When seismologists preformed detailed studies _____, they found that the earthquakes occur in an inclined zone that extended several hundred miles down into the mantle

Near ocean trenches

Because Werner lacked a mechanism of continental movement, continental drift was ______

Not widely accepted by the scientific community

Basaltic magma generated from melting asthenosphere rises at mid-ocean ridged to form _____ lithosphere

Oceanic

The western cost of South America and the Pacific Northwest are both examples of _______ boundaries

Oceanic-continental convergent

Volcanic Island arcs are formed at

Oceanic-oceanic convergent plate boundaries

The nonrandom distribution of which two natural resources are most directly related to the rock cycle and plate tectonics?

Oil and mineral

Alfred Wegener reassembled the land masses of Asia, Australia, Europe, Africa, India, North America, and South America into a supercontinent he called ______

Pangea

Andesitic magma is created when basaltic rock

Partially melts and creates a more silica-rich magma

Earths internal heat causes the rigid pieces of Earth's crust to move in relationship to one another. This is the theory of _____ ______.

Plate tectonics

Convergent plate boundaries have which type of movement?

Plates coming together

Scientists have been able to confirm that subduction is taking place by systematically _____, which indicate that lithospheric slabs are descending into the mantle

Preforming detailed seismic studies

Uranium, thorium, and potassium are _____ elements that give off heat when they decay, providing Earth with a source of internal energy.

Radioactive

A seismic wave moving in Earth may either ______ (bounce off) or _____ (bend) when encountering a different layer of material

Reflect; refract

2 main sources of Earth's internal heat are radioactive decay and ______ heat from planetary formation

Residual

What is the process in which rising mantle material at a divergent boundary pushes the lithosphere upward, causing the elevated oceanic plate to slide downward over the sloping surface of the asthenosphere?

Ridge push

Why is seismic risk less severe at divergent boundaries compared to convergent and transform boundaries

Rocks store more energy before returning when under compression or shear forces, compared to tension

The _______ is a well-known transform plate boundary

San Andreas fault

slab pull

Slab sinks and drags rest of the plate into the subduction zone

The deformation of rocks under stress is called ____

Strain

When force is applied to an object, that object is under _____

Stress

The process of lithospheric slabs descending into the mantle is called

Subduction

Because rocks store more energy before rupturing when under compression or shear forces when compared to _____, major quakes are less common along divergent boundaries

Tension

Which of the following represents a spreading center in the earliest stage of development?

The African great Rift Valley is

What type of evidence collected by ocean research drilling rigs in the late 1960's confirmed seafloor spreading?

The age of basalt on the sea floor

Divergent plate boundaries have what type of movement?

The plates are pulling apart

Magnetic reversal occurs when

The polarity of Earth's magnetic field changes

Two plates moving in opposite directions in a shearing motion occurs at

Transform plate boundaries & transform faults

Ocean ______ are narrow, steep-sided depressions with depths as great as 36,000 feet (11,000 m) below sea level

Trenches

A common occurrence at oceanic-continental convergent plate boundaries are

Volcanic mountain belts

Compared to the Lithosphere, the Asthenosphere is

Weaker and more easily deformed

3 major types of plate boundaries

divergent, convergent, transform

Seafloor spreading is

the process by which new oceanic crust is made as the plates separate and move away from each other