Physical Geology test 1

How old is the Earth?

4,600,000,000 years

Approximately how old is our solar system?

4.6 Billion years

Which scientist developed the Continental Drift hypothesis?

Alfred Wegener

What property of the crust allowed it to form as the exterior of Earth?

Materials that make up the crust are less dense and rose to the top

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? How to solve this problem: 1. Determine how many half lives are present. 2. Multiply the number of half-lives by 100,000 (because each half-life is 100,000 years)

300,000 years

What is the definition of the asthenosphere?

A soft, low-velocity layer in the Upper Mantle

What geologic era do you live in?

Cenozoic

Which best explains why identical Mesosaurus fossils are found on different sides of the Atlantic Ocean?

Continental Drift

_______________ is thick (30 - 75 km), old, composed of felsic (granitic) silicates, light (~2.7 g/cm3), and highly deformed by folding.

Continental crust

Which is the oldest eon?

Hadean

Which of the Earth's spheres contains all of the solid, liquid, and gaseous water on Earth?

Hydrosphere

Which geoscientist was the first to introduce the idea of geological (or deep) time?

James Hutton

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

Lithosphere

The Phanerozoic eon is divided into three eras. Which of the following is NOT one of those eras?

Neogene

The supercontinent in the Continental Drift hypothesis was called ___________

Pangaea

Which would generally NOT be involved in determining the relative age of rock strata?

Radioactive decay

Harry Hess' theory of __________ explained how ocean crust is generated and destroyed

Seafloor Spreading

What was Marie Tharp's contribution to geology?

She mapped the ocean floor and discovered a huge (rift) valley in the center of the (previously discovered) mid ocean ridge

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 ("the how?")

This principle is often stated as "the present is the key to the past"

Uniformitarianism

Geologist Nick finds that unit F contains eroded pieces of unit G. Which of the following statements is true?

Unit G is older than unit F

A nonconformity is _________ .

a gap in the geologic record bounded below by metamorphic or igneous rocks and bounded above by sedimentary rocks

A disconformity is ___________ .

an erosional surface between horizontal sedimentary rocks

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

carbon-14

If you wanted to search for really, really old (i.e. billions of years old) rocks to date , would you go looking for continental rocks or oceanic rocks?

continental rocks

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

crust

Seafloor spreading occurs along mid ocean ridges and is associated with __________________________________ plate boundaries.

divergent

Order the divisions of geologic time from the longest to the shortest.

eons, eras, periods, epochs

Solar Nebula Theory explains the formation of the universe.

false

The Red Sea is an example of:

initial rifting of a continent

_______________________________ are atoms with the same atomic number but different mass numbers.

isotopes

Why is there an elevated intraplate earthquake risk for portions of Missouri, Arkansas, Tennessee, Kentucky, and Illinois?

it's located on a current transform plate boundary

The ________________________________ is Earth's strong, rigid outer layer.

lithosphere

Basaltic rocks contain ___________________ (Fe3O4), an iron-rich mineral influenced by Earth's magnetic field.

magnetite

In which layer of Earth does the convection necessary for plate motion occur?

mantle

The Hawaiian Islands are thought to have been formed at a ____________.

mantle plume/ hot spot

The study of fossil succession allows ___________ .

matching of similarly-aged rocks from different outcrops

A divergent boundary is a boundary between two plates that __________.

move away from each other

When did geologists develop the theory of plate tectonics? (hint: Development of plate tectonics followed by the concept of seafloor spreading of Harry Hess)

n the 1960's

Rocks having same magnetism as the present magnetic field exhibit _______________________________.

normal poloarity

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

older --- younger

Ocean floor sediments become ________________________________________ as you move further away from a mid ocean ridge.

older/thicker

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

outercore

What scientific avenue of investigation gave scientists the best estimate of Earth's actual age?

radiometric dating

The principal of original horizontality states that ________ .

sediments are deposited as essentially horizontal layers

Divergent boundaries are places where:

shallow focus earthquakes occur, new ocean lithosphere is created, basaltic lava erupts from volcanoes

__________________ are scratches or gouges cut into bedrock by glacial abrasio

straitions

True or false. Earth's magnetic field occasionally reverses its polarity.

true

~13.8 billion years ago, the Big Bang created the _____________ from a point source.

universe

Who is credited with developing the principle of fossil succession?

william smith