Geology multiple choice from textbook

for exam one

What distinguishes science from pseudoscience?

 B. Concepts must be falsifiable to be considered science.

 Why is science normally a slow process?

 C. The process of weeding out misinformation and verifying results takes time.

In the scientific method, which of these steps would normally follow experimentation and sharing of results?

C. Peer review

 Igneous rocks form by

 B. crystallization

 Which layer of the Earth is liquid?

B. Outer core

 In the scientific method, which step would normally follow observation?

C. Hypothesis development

Fossils and rocks

contiental drift

coastlines

continetal drift

warm places glaciated

continental drift

cooler places with tropical fossils

continetal drift

GPS measurements

plate tectonics

Mid-ocean ridge found

plate tectonics

ocean trenches found

plate tectonics

lined-up earthquakes

plate tectonics

Paleomagntism showing moving rocks

plate tectonics 

How did scientists first figure out plates could sink into the interior of the planet, since no one can see this happening?

C. Lines of progressively-deeper earthquakes near arcs and trenches

 Which of the following are NOT evidence Wegener used to construct the idea of Continental Drift?

A. Earthquake locations lined up with crustal features

The lowest density layer is the

crust

The highest density layer

Inner core

The only liquid layer

Outer core

The largest layer by volume

Mantle

The layer plates are made from

Lithosphere 

The layer that moves the plates around

Asthenosphere

 Which layer of the Earth can move internally or flow to allow the plates to move around on it?

A. Athenosphere

What makes continental plates different than oceanic plates?

C. Continental plates are ductile and can flow internally

 What term is used for a boundary between a continent and an ocean basin without relative motion between them?

B. Passive

Why do high mountains like the Alps and Himalayas form when continents collide?

B.) The materials of continental plates are similar in density and don’t subduct beneath one another

 What feature is associated with crustal divergence?

C.) Mid-ocean ridge

 Why do continents generally not subduct?

B) Continents are too low in density to subduct

 Which of these are features found at rift zones?

C.) Grabens and Faults and rifts at 120° angles

 What happens as newly formed oceanic crust moves away from the mid-ocean ridge?

 C) The crust gets colder

 Other than mid-ocean ridges, where on Earth is the best example of current (active) rifting?

 B) East Africa

How is magma generated at divergent boundaries?

 A) Decreased pressure

As a rift forms on a continent, what feature can form next?

C) Ocean basin

 What famous transform fault is known for being the boundary between the Pacific Plate and North American Plate in California?

C) San Andreas fault

 What type of motion occurs at a transform boundary? Plates move

C.) side to side

 What makes transform boundaries different than other boundaries?

B.) Transform has less volcanoes

 Why are piercing points important with transform boundaries?

 A) They track movement

 What are the ways transform faults move?

A) Left (sinistral) and right (dextral)

 According to the Wilson Cycle, what feature or process is most likely to occur after collision and formation of a supercontinent?

C.) Rifting 

What features or processes are common in hot spots?

B) Volcanism

 A line of shallow earthquakes with little or no volcanism is likely evidence of what type of plate boundary

C.) transform

 Which plate boundary has the largest and deepest earthquakes?

 A) Subduction 

Why did Alfred Wegener never get the support of the scientific community for his hypothesis of continental drift during his lifetime?

A.) He could not provide a mechanism for how continents moved

 We are not able to get rocks from deep within the Earth. What is the most direct source of information that allows us to draw conclusions about the interior?

 B) Seismic waves

 Of these, what boundary generally produces new liquid magma?

C) Subduction

 What happens to the crust as you move towards the mid-ocean ridge?

 A) the crust gets younger 

 Which plate boundary is least likely to be dangerous to humans?

B) Rift  

 Which tectonic setting places the asthenosphere farthest from the surface

 A) Continental collisions

 What is the biggest difference between hot-spot volcanism in an island chain and plate tectonic volcanism in an island chain?

C) Hot spots have age trends

 Minerals have a crystalline structure. What does this mean?

A) That the atoms are arranged in an orderly, repetitive manner

When a positively-charged sodium ion is chemically bonded with a negatively-charged chlorine ion to make sodium chloride (i.e. the mineral halite), this is an example of _____.

 A) ionic bonding

Which of the following does not cause an increase in mineral precipitation?

B) Heating a fluid

 What is the most common mineral formed by life?

C) Calcite

 When a mineral precipitates from solution, it ____________.

 A) crystallizes into a crystal

What is the most common origin of carbonate minerals in nature?

 A) Made by marine life

 Which of the following is true about minerals?

A.) Minerals can only be made naturally

Select one process by which minerals are NOT made?

C) Freezing of water

What controls a mineral’s color?

A.) Elements present

 Which of these is actually a mineral?

C) apatite in your collar bone

Where do igneous rocks with a coarse-grained (phaneritic) texture form?

C) deep under the surface.

How does the silica content affect the behavior of magma?

A.) Higher silica makes the magma more viscous

Which rock composition has the most amount of iron and magnesium?

C) mafic

 What causes igneous rocks to develop a fine-grained (aphanitic) texture?

B.) Fast cooling

 A basaltic intrusion that cuts across layers of sedimentary rocks is called a _______.

B) dike

 What is the process by which decompression melting produces magma at divergent plate boundaries?

 B) reduction of pressure at constant temperature

 The crystallization process in which a rising magma diapir incorporates some of the surrounding country rock so that the chemistry of the magma changes is called _____.

 B) assimilation

 Unmelted pieces of country rock incorporated within the igneous rock mass are called _______.

 B) xenoliths

 Crystal settling would be another name for ______.

 A) fractional crystallization

 Partially melting an ultramafic rock produces a magma with a(n) _________ composition.

A) felsic

Explosive silica-rich volcanoes will be located mostly at ______.

C.) convergent plate boundaries with subduction zones

 Deep-sea hydrothermal vents (black smokers) are most commonly located at what plate boundary?

C) divergent boundaries of the mid-ocean ridge

 The largest type of volcano is called a _______ volcano and is characterized by broad, low-angle flanks, a small vent or groups of vents at the top, and basaltic magma.

 B) shield volcano

 A __________ is a volcanic hazard arising from a collapsing eruption column that runs downhill at high speeds (>100 mph). These are associated with explosive eruptions and a mix of lava lapilli, pumice, ash, and hot gases.

A) pyroclastic flow

 A _______ volcano has steep flanks, symmetrical cone shapes, distinct crater at the top, and a silica-rich magma that results in an explosive eruption style.

A) stratovolcano

Which of these relatively recent volcanic eruptions formed a caldera?

 A) Yellowstone

What kind of volcanoes make up the Hawaiian Island Chain?

 B) shield volcanoes

 Most volcanoes on the sea floor erupt ________.

C) Quietly with basaltic magma

 Why does partial melting occur?

A) Because some minerals have lower melting points than others

 Which of these is NOT a means by which magmas are generated in the Earth?

C) Liquid melting

 What does the Bowen Reaction Series show about the mineral composition of igneous rocks?

A) form in separate groups that depend on the temperature at which they crystallize.

 Bowen’s Reaction Series has been expressed as a Y-shaped diagram containing how many minerals?

B) 8  

 A rock with aphanitic texture and dark color is best identified as a _______________.

 A) Basalt

 A pegmatite is characterized by __________ that forms from __________.

C) Very large crystals of felsic composition; very slow cooling of residual material expelled from cooling magma

 A porphyritic igneous rock has what defining characteristic?

 B) Larger crystals in a finer grained groundmass

 Where do igneous rocks with a coarse-grained (phaneritic) texture form?

 C) Deep under the surface

 How does the silica content affect the behavior of magma?

 A) Higher silica makes the magma more viscous

 Which rock composition has the most amount of iron and magnesium?

 B) Ultramafic

 What causes igneous rocks to develop a fine-grained (aphanitic) texture?

B) Fast cooling

When did Mount Pintubo first begin to show signs of activity?

A) Spring 1991 

Volcanic emissions of which type of gas indicates that magma is rising beneath a volcano?

B) SO2