Geology hw 1 review

Plate movement is NOT influenced by

mantle plumes, which are created when hot rock rises up from the deep mantle and creates melting at the base of the lithosphere

The center of mid-ocean ridge is where

new oceanic lithosphere is created

Magnetic anomalies are

places where the magnetic field strength is either greater or less than the expected strength

According to current plate tectonics theory

plates are composed of the crust and the uppermost part of the mantle

The apparent tendency of the north (or south) magnetic pole to vary in position over time is termed

polar wander

Which process is responsible for the formation of the Red Sea

rifting followed by seafloor spreading

The global occurrence of earthquakes reveals that

they usually occur on the boundaries of plates or at hot spots

Seafloor spreading is driven by volcanic activity that occurs

along mid-ocean ridges

a seamount chain is

an elongate series of former volcanic islands that poke up from the ocean floor

The Earth's magnetic field is created by

flow of liquid iron in Earth's molten outer core

The ____ concept placed Earth at the center of the Universe, with the other planets and the Sun revolving around it. The ____ concept placed the Sun as the center, with Earth and the other planets revolving around it

geocentric; heliocentric

Alfred Wegener's idea of continental drift was rejected by American geologists because

he could not conceive of a valid mechanism that would cause continents to shift positions

True or false: Apparent polar-wander paths for different continents do not match, so each continent must be moving independently of others

true

Deuterium and Tritium come together. Created Helium and ejects a neutron

two atoms combing during nuclear fusion

The heliocentric model

was supported by observations that planets follow an elliptical orbit

What statements are true of fracture zones

1. Fracture zones can act as transform boundaries between two actively spreading ridge segments 2. Earthquakes can occur along fracture zones 3. Fracture zones are situated perpendicular to mid-ocean ridge segments

What variables could influence the width of marine magnetic anomalies on the floor of the ocean?

1. Rate at which the plates are moving away from the mid-ocean ridge 2. duration of the magnetic polarity event

According to the theory of plate tectonic, the plates are:

1. discrete pieces of lithosphere which move with respect to one another 2. moved by the creation of new crust and subduction of old crust

Big Bang theory

1.All matter in the Universe was once confined to a single point 2. The Universe is considerably older than Earth 3. It began with all matter and energy concentrated in an infinitesimally small point

Modern plate tectonic theory was developed in what decade?

1960s

Order the steps of volcanic island arc formation: 1. An accretionary prism begins to form 2. A subduction trench forms where the subducting plate bends downward into the mantle 3. Lava erupts onto the surface, forming volvanes 4. Magma, created by flux melting of the mantle, rises through the overriding plate

2. A subduction trench forms where the subducting plate bends downward into the mantle 1. An accretionary prism begins to form 4. Magma, created by flux melting of the mantle, rises through the overriding plate 3. Lava erupts onto the surface, forming volvanes

Order the steps that lead to seafloor spreading: 1. A magma chamber forms beneath the ridge axis 2. The asthenosphere beneath diverging plates rises and melts 3. Newly formed crust is moved laterally away from the ridge 4. Magma rises to the surface and erupts via submarine volcanoes

2. the asthenosphere beneath diverging plates rises and melts 1. a magma chamber forms beneath the ridge axis 4. Magma rises to the surface and erupts via submarine volcanoes 3. newly formed crust is moved laterally away from the ridge

Why is the oldest seafloor generally less than 200 million years old?

All oceanic lithosphere eventually gets subducted beneath the continents by the time it is 200 million years old

Order smallest to largest: Earth, Asteroid, Sun, Jupiter, Mars

Asteroid, Mars, Earth, Jupiter, Sun

Which is True: A) The Sun accounts for almost 50% of the Solar System's mass B) The only two planets with moons are the Earth and Jupiter C) Our Sun is the only star we know of that has planets associated with it D) The composition of the giant planets is mainly gas and "ice"

D) The composition of the giant planets is mainly gas and "ice"

Transform boundary

Earthquakes

According to nebular theory, the progression from planetesimal to full-fledged planet is propelled mainly by which of the following?

Gravity

Marine magnetic anomalies result from seafloor spreading in conjunction with

Magnetic polarity reversals

Order largest to smallest: Protoplanet, Planet, Planetesimal

Planet, Protoplanet, Planetesimal

How did military during WW2 get images of the seafloor?

Sonar

The reversals of the Earth's magnetic field were first discovered by

Studying the paleomagnetism of volcanic rocks

True or false: Positive magnetic anomalies occur where seafloor basalt has the same polarity as Earth's present-day magnetic field

True

True or false: Some magma generated during seafloor spreading erupts from submarine volcanoes to form basalt

True

True or false: Trenches occur at subduction zones

True

What feature protects Earth against high-energy cosmic radiation and very fast-moving solar wind particles?

Van Allen radiation belts

Wegener's theory of continental drift took decades to be accepted because?

Wegener couldn't explain how continents moved

What issues initially prevented widespread acceptance of Alfred Wegener's continental drift hypothesis?

Wegener's Lack of a good Mechanism to explain why the continents moved

The Himalayas are growing becuase

a continental plate is colliding with another continental plate is there

The island of Hawaii is the youngest, and the islands get progressively older to the northwest. Plate tectonic theory explains this as

a hot spot currently sitting under Hawaii and the Pacific Plate moving across it in a northwesterly direction

Identify how heavier elements form: a) in stars b) during supernovae explosions c) during accretion d) during the Big Bang

a) in stars b) during supernovae explosions

Which 2 statements are true? a) The moon formed as a result of differentiation b) The core formed as a result of differentiation c)The mantle formed as a result of differentiation d) The Earth is round because of differentiation

b) The core formed as a result of differentiation c) The mantle formed as a result of differentiation

What is the stream of charged particles given off from the sun called? a) the aurora borealis b) solar wind c) the van allen belts d) the Sun's corona

b) solar wind

The rate of plate motion

can be expressed as relative plate velocity, which describes movement of one plate in relation to another plate

Fossils, glacial deposits, and the fit of the continents suggested all of the continents were once

combined to form a supercontinent called Pangaea

The San Andreas fault is

one of the few transform faults that cut across continental lithosphere.