geology exam

Approximately how old is the oldest oceanic crust?

200 million years old

Atoms of AA decay to atoms of BB with a half-life of 100,000 years. If there are 20,000 atoms of AA to begin with (and 0 atoms of BB), how long will it take for there to be 2,500 atoms of AA? Hint- how many half-lives have elapsed?

300,000 years

How many neutrons are in an atom of 6C12?

6

Which is the best explanation for the formation of the moon?

A planetesimal the size of Mars struck the earth, ejecting large volumes of matter. A disk of orbiting material was formed, and this matter eventually condensed to form the Moon in orbit around the Earth

Which of the following best describes the material that makes up the Earth's asthenosphere?

A solid that is able to flow

a very massive star may collapse and explode at the end of its life. This is a

A supernova

Who proposed Continental Drift?

Alfred Wegener

The horizontal line labeled X-X' is a(n) ________ .

Angular unconformity

A(n) ______________ is a negatively charged element or element group such as Cl- or CO3 -2

Anions

Radiometric dating is possible if a rock contains a measurable amount of ________ .

Both parent and daughter isotopes

Which of the following radioactive isotopes is most useful for dating a very young sample (<20,000 years) of wood?

Carbon-14

What type of mineral is calcite (CaCO3)?

Carbonate

You live in the ________________ era.

Cenozoic

________________ is thick (30 - 75 km), old (up to 4,400,000,000 years), composed of felsic (granitic) silicates, light (~2.7 g/cm3), and is highly deformed by folding

Continental crust

H2 is an example of which type of bonding?

Covalent

Which geologic principal was most useful in determining the answer in the preceding question?

Cross-cutting

Which is the youngest feature in the figure below?

Dike A

. A _____________ plate boundary is illustrated in the figure below.

Divergent (ocean-ocean)

The only layer of the Earth that is a liquid is the

Earth's outer core

Which of the following is the correct order from LONGEST to SHORTEST time span?

Eon, Era, Period

Who actually figured out that radioactive decay can be used to date rocks?

Ernest Rutherford

The cross sections of crust below represent two regions of sedimentary rock layers that have been altered. The sedimentary bedrock in both regions originally formed as ________________.

Horizontal layers

When did geologists develop the theory of plate tectonics?

In the early 1900's

The Earth's core is composed mainly of

Iron

______________ describes two atoms with the same atomic number but different mass numbers.

Isotopes

was a classical and biblical scholar who created a careful and critical chronology of human history, including the date of the Creation of the Earth (4004 BC).

James Ussher

Uranium-238 decays to which of the following daughter isotopes?

Lead-206

Tyrannosaurus Rex lived during the Upper Cretaceous period (roughly 100-66 Ma ago) in the ________________era.

Mesozoic

An undeformed sedimentary layer is __________ than the layer above and ____________than the layer below.

Older, younger

Magnetite (Fe3O4) is a member of which mineral group?

Oxides

36. The supercontinent in the Continental Drift hypothesis was called ___________

Pangaea

Both you and Tyrannosaurus Rex live (lived in the case of T-Rex...) in the _____________ eon.

Phanerozoic

Which of the following is NOT one of the several naturally occurring radioactive isotopes useful for dating rocks?

Potassium-40

Which of the following represents the longest time period?

Precambrian

Each element has a unique number of :

Protons

Which of the following is a geographic example of a transform boundary?

San Andreas Fault

Approximately how fast does a tectonic plate move?

Several centimeters per year

Clay minerals are common examples of _________ silicate structures.

Sheet silicates

Which of the following is NOT included in the definition of a mineral?

Specific orderly crystalline structure

. __________________ are scratches or gouges cut into bedrock by glacial abrasion

Striations

. The descent of oceanic lithosphere into the mantle is the process of ______.

Subduction

Which of the following principles CANNOT be used to determine the relative age of rocks?

The Principle of Relative Sequencing

The map below shows the present-day locations of South America and Africa. Remains of Mesosaurus, an extinct reptile, have been found in similarly aged bedrock at locations X and Y. Which statement represents the most logical conclusion to draw from this evidence?

The continents of South America and Africa were joined when Mesosaurus lived.

What was the main reason the Continental Drift hypothesis was rejected?

The scientist who proposed it could not provide a mechanism for the movement of the continents

Which of the following units is the youngest?

Unit A

George Geologist finds that unit F contains eroded pieces of granite (unit G). Which of the following statements is true?

Unit F is younger than Unit G

What is the most common structural element of the silicate mineral group?

a silicon-oxygen tetrahedron

A disconformity is ___________.

an erosional surface between horizontal layers of sedimentary rocks

The lithosphere is made up of the upper-most mantle and the

crust

________________ is/are the most common member of the silicate group, comprising more than 50% of Earth's crust.

feldspar

Evidence about ancient climates indicates that ____________.

glacial ice once covered much of what is now India and Australia

Which of the following statements about convection is true?

hot material flows upward and displaces cool material

Where did heavier elements come from?

in a supernova explosion

Atoms that have gained or lost electrons are no longer electrically neutral are called :

ions

Which is the thinnest physical (mechanical) layer of the Earth?

lithosphere

What do the stripes represent?

magnetic reversals

The study of fossil succession allows ___________.

matching of similarly-aged rocks from different outcrops

Which of the following features is not associated with a convergent plate boundary?

mid ocean ridge

An example of modern continental rifting (divergent plate boundary) is

mid-atlantic ridge

New seafloor is created at a ____________?

mid-ocean ridge

. In the plate tectonic theory, a plate can be made up of ____.

oceanic and continental crust

The two most abundant elements in the Earth's crust are _______________.

oxygen and silicon

Which of the following was NOT used in support of the Continental Drift hypothesis?

paleomagnetism

The atomic mass number of an element is the __________.

protons plus neutrons

Which of the following minerals does NOT belong to the Native Element mineral group?

quartz

Most common rock-forming minerals are ______________.

silicates

According to the theory of plate tectonics, ____

slow motions within the mantle of the Earth move large sections of the crust around

13.82 billion years ago, the Big Bang created the __________ from a point source.

universe