Penn State GeoScience 1 Final Exam

The image below depicts the formation of what tectonic feature?

A) Tephra

B) Accretionary prism

C)Ripples

D) Pillow lavas

E) Subduction currents

B) Accretionary prism

At which plate boundary type might you find this feature?

A) Transform fault

B) Fracture Zone

C) Hotspot

D) Subduction Zone

E) Divergent Mid-Ocean Ridge

D) Subduction Zone

The age of the earth is closest to:

A) 2.5 billion years

B) 3.5 billion years

C) 4.5 years

D) 5.5 billion years

E) 20 billion years

C) 4.5 billion years

The age of the earth is known from:

A) The oldest volcanic rocks on Greenland

B) Dating meteorites using the decay of radioactive elements

C) Fossil algae in oldest rocks

D) Magnetic reversals of the oldest metamorphic rocks

E) Greek mythology

B) Dating meteorites using the decay of radioactive elements

Which of the following statements IS true?

A) The earth formed from a different ring in the nebula than the other planets

B) On formation, the atmosphere was too hot for water vapor to condense

C) The terrestrial planets are denser than the Jovian planets

D) Initially the earth was homogeneous

E) All of the above statements are true

E) All of the above statements are true

The 'Iron Catastrophe' involved which of the following?

A) Melting and concentration of iron/nickel at the Earth's core

B) Eruption of iron rich magmas killing all life on early Earth

C) Poisoning of early cells by iron-rich bacteria

D) All of the above

E) None of the above

A) Melting and concentration of iron/nickel at the Earth's core

The three most abundant elements in Earth's crust are:

A) Si, Al, and Fe

B) Si, Fe, and O

C) Ca, Al and Mg

D) Si, Al, and O

E) Si, Ca, and Mg

D) Si, Al, and O

Approximately how thick is the crust under a mid ocean ridge?

A) 25km

B) 10km

C) 40km

D) 80km

E) 30km

B) 10km

Which of the following are equivalent (and correct)?

A) Lithosphere: upper-middle-lower mantle

B) Asthenosphere: upper-middle-lower mantle

C) Liquid core: inner core

D) Plates: lithosphere and upper asthenosphere

E) None of the above are equivalent and correct

E) none of the above are equivalent and correct

How is the depth of the crust defined?

A) Heat flow measurements

B) Drilling

C) The Mohorovicic seismic discontinuity

D) Magnetic probe surveys

E) None of the above

C) The Mohorovicic seismic discontinuity

Where is continental crust the thickest?

A) Underneath tall mountain ranges

B) Underneath continental shelves

C) Underneath transform faults

D) Underneath trenches

E) A and C

A) Underneath tall mountain ranges

In 1912 Afred Wegner proposed the idea of continental drift, which of the following information did he NOT use as evidence for continental drift?

A) Similar rock formations in mountain chains on different sides of oceans

B) Glacial formations on different continents

C) Identical fossil reptile species found in Africa and South America

D) Magnetization of accretionary prism rocks

E) All of the above

D) Magnetization of accretionary prism rocks

Continental Drift is thought to be the predecessor of modern Plate Tectonic Theory. What was missing from Wegener's theory?

A) Data

B) Knowledge of Earth's rotation

C) A driving mechanism

D) Knowledge of the interior of the Earth

E) None of the above

C) Driving mechanism

What data were used for evidence of apparent polar wander?

A) Magnetism

B) Seismicity

C) Gravity

D) Seafloor Magnetic Anomalies

E) Paleo-poles derived from rock magnetism

E) Paleo-poles derived from rock magnetism

Which of the following is NOT true regarding the Earth's magnetic field?

A) The magnetic field is recorded in many rocks when they form

B) Reversals of the field are not global events

C) The field results from fluid motions in the outer core

D) The field reverses periodically

E) The inclination at the poles is vertical

B) Reversals of the field are not global events

What was Pangea?

A) A genus of reptiles that ruled the world 150 million years ago

B) A mountain chain that circled the globe 300 million years ago

C) A super continent proposed by Alfre Wegener that existed 250 million years ago

D) A type of highly iron rich magma found in trap lava eruptions

C) A super continent proposed by Alfre Wegener that existed 250 million years ago

How are the organisms associated with mid-ocean ridges unusual?

A) They thrive on very low levels of photosynthesis

B) They have symbiotic relationships with deep-sea fish

C) Their average life span is over 500 years

D) They us chemicals as a source of energy

E) They eat dirt

D) They use chemicals as a source of energy

Which is a true statement about magnetic reversals at divergent boundaries?

A) There are no magnetic reversals recorded in the oceanic crust

B) Since there have been no reversals in the last 50 million years, they can't be seen

C) An identical sequence of reversals is found in either side of a mid-ocean ridge

D) The rock is too hot for reversals to be measured

E) All of the above

C) An identical sequence of reversals is found on either side of a mid-ocean ridge

The importance of marine magnetic anomalies is that they:

A) Allow one to estimate the rate of plate divergence

B) Demonstrate the theory of seafloor spreading

C) Demonstrate that the Earth's magnetic field reverses periodically

D) A,B, and C

E) None of the above

D) A,B, and C

How are hot spots produced?

A) Plumes of heat from the mantle

B) Sediments melting the uppermost crust

C) Seawater entering the volcano system

D) Compression melting of a thick slab

E) Plumes of melt from the mantle

E) Plumes of melt from the mantle

Which of the following features is associated with a convergent boundary?

A) The Mississippi River

B) The Grand Canyon

C) Mt St Helens

D) Death Valley

E) Michigan Stadium

C) Mt St Helens

What type of magma erupts at divergent boundaries?

A) Andesite

B) Basalt

C) Rhyolite

D) Sandstone

E) Quartz

B) Basalt

Which of the following are NOT usually associated with subduction zones?

A) Trenches

B) Island arcs

C) Back arc basins

D) Accretionary prisms

E) Continental Rifts

E) Continental Rifts

(Trenches are at subduction zones)

Why does the elevation of the crust decrease away from mid-ocean ridges?

A) Because volcanism increases

B) Because of diffusion

C) Because the crust cools and becomes thicker and more dense

D) Because the amount of water increases

E) Sediment deposited on top of tis weighs it down

C) Because the crust cools and becomes thicker and more dense

Which direction does the Benioff zone descend from the trench into the mantle?

A) Towards the volcanic arc

B) Away from the volcanic arc

C) A and B

D) None of the above

E) Toward the poles

A) Towards the volcanic arc

How does water contribute to magmatism at convergent boundaries?

A) It lowers the melting point of the mantle wedge above the subducting plate

B) It decreases pressure on the sediment pile

C) It drives back-arc spreading

D) It cause earthquakes, fracturing and magma flow

E) None of the above

A) It lowers the melting point of the mantle wedge above the subducting plate

Which direction is the Pacific Plate moving in the vicinity of Los Angeles?

A) NE

B) NW

C) SW

D) N

E) S

B) NW

What are the dominant forces at divergent boundaries?

A) Extension

B) Ridge push

C) Lateral Shear

D) A and C

B) ridge push

Where do arc basins form?

A) Ocean-continent convergence subduction zones

B) Continent-continent collisions

C) Transform faults

D) Ocean-ocean convergence subduction zones

E) None of the above

D) Ocean-ocean convergence subduction zones

What is a typical rate of plate motion?

A) 1 micron/year

B) 1mm/year

C) 1 cm/year

D) 1m/yr

E) 1km/yr

C) 1cm/yr

Plate motions are measured using?

A) Marine magnetic anomalies

B) The strike of transform faults

C) Earthquakes

D) The Global Positioning System

E) A and D

E) A and D

At which location does rifting of a continent often begin?

A) An ancient transform fault

B) An ancient mid ocean ridge

C) A suture zone

D) An ancient trench

E) All of the above

B) An ancient mid ocean ridge

What is a failed rift?

A) A mid ocean ridge system that stops spreading

B) A mid ocean rift valley that is choked with volcanoes

C) A continental rift that stops opening

D) A mid ocean ridge that merges with a subduction zone

E) A and C

E) A and C

How did the Appalachian Mountains form?

A) Form repeated collisions of continents on opposing sides of the Atlantic

B) From subduction of the seafloor under an arc along the Pacific coastal plain

C) From strike slip transform motion along the rifted east coast margin

D) From doming of the crust at the beginning of the rifting process

A) From the collisions of continents on opposing sides of the Atlantic

Which of the following are TRUE?

A) Heat increases with depth

B) Pressure decreases with depth

C) Both A and B

D) Pressure increases with depth

E) A and D

E) A and D

What is the significance of mantle xenoliths?

A) They tell us about the composition of the Earth's core

B) They tell us about the composition of the Earth's crust

C) They tell us about the composition of the Earth's mantle

D) They tell us about the composition of the Earth's lithosphere

E) They tell us that the Earth is made of string cheese

C) They tell us about the composition of the Earth's mantle

*What type of unconformity lies above igneous or metamorphic basement?

A) A nonconformity

B) An angular unconformity

C) A paraconformity

D) A disconformity

E) None of the above

E) None of the above

Which period comes after the Silurian?

A) The Triassic

B) the Permian

C) The Ordovician

D) The Cretaceous

E) The Devonian

E) The Devonian

Which period comes before the Triassic?

A) Jurassic

B) Permian

C) Pennsylvanian

D) Cretaceous

E) Silurian

B) The Permian

Which is the oldest eon?

A) Archean

B) Paleozoic

C) Proterozoic

D) Mesozoic

A) Archean

Which is true?

A) A numerical age is given in years

B) A numerical age is related to magnetic reversals

C) A relative age is the age of your uncle

D) A relative age describes the age of one event relative to another event

E) A and D

E) A and D

Layering within the interior of the Earth is defined by:

A) The Mohorvicic Discontinuity

B) Chemical variations

C) Physical variations

D) Rheological variations

E) B,C, and D

E) B,C, and D

The Wilson Cycle describes:

A) The motion of continents

B) The opening and closing of oceanic basins through plate tectonics

C) The lunar cycle

D) The solar cycle

E) None of the above

B) The opening and closing of oceanic basins

Why is the oceanic lithosphere able to subduct after 100,000 years?

A) It is less dense then continental lithosphere

B) It is less dense than the asthenosphere

C) It is denser than the asthenosphere

D) It is saturated with seawater

E) It is more dense than seawater

C) It is denser than the asthenosphere

Cleavage in a mineral is controlled by which of the following?

A) Planes along which bonding is weak

B) The predominant direction light is transmitted through a crystal

C) Linear chains of oxygen atoms

D) Breakage planes caused by high pressure

E) Cracks formed by applied high temperature

A) Planes along which bonding is weak

SiO2 is the chemical composition of which of the following minerals?

A) Gypsum

B) Amphibole

C) Halite

D) Pyroxene

E) None of the above

E) None of the above

(Mg, Fe)SiO4 is the chemical composition of which of the following minerals?

Olivine

The Doppler Effect was used to demonstrate what about the Universe?

A) It is contracting

B) It stopped expanding

C) It is a black hole

D) None of the above

C) It is expanding

How many unconformities (including all three types) are there?

A) 0

B) 1

C) 2

D) 4

E) 6

D) 4 (count the squiggly lines)

Which is the oldest of the following?

A) Fault P

B) Dikes S

C) Fault K

D) Dike E

C) Fault K

What is a correct sequence of ages from oldest to youngest?

A) B, K, M, G, D

B) X, B, Z, A, L

C) C, M, K, S, P

D) O, M, E, K, A

E) None of the above

C) C, M, K, S, P

After three half lives how many parent atoms will be left if there were 4 million originally?

A) 2 million

B) 1 million

C) 500,000

D) 400,000

E) 100,000

C) 500,000

Which statement IS true about radioactive decay?

A) It occurs at a constant rate

B) It occurs at a slow, variable rate

C) It occurs at an exponential rate

D) It is a finite process

E) It occurs slowly at first, then speeds up

C) It occurs at an exponential rate

Which of the following could you date with radiocarbon (C-14)?

A) A volcanic quartz grain 10,000 years old

B) A 25,000 year old tree

C) An oyster 10 million years old

D) Remains of a million year old bone

A) A volcanic quartz grain 10,000 years old

The hydrologic cycle describes the processes by which water cycles through the atmosphere, biosphere, hydrosphere, and lithosphere. Which of the following is NOT part of the hydrologic cycle?

A) Transpiration

B) Evaporation

C) Infiltration

D) Erosion

E) Precipitation

D) Erosion

Stream runoff is an important geologic agent, because:

A) Streams erode, transport and deposit sediment

B) Sculpt landscapes

C) Transfer mass form the continents to the oceans

D) None of the above

E) A, B and C

E) A, B, and C

Which hydrologic cycle process is important for adding water to streams?

A) Infiltration

B) Transpiration

C) Precipitation

D) A and C

E) None of the above

D) A and C

Smaller streams that flow into a trunk stream are called?

A) Trun

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