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