Geology Exam Part #2
In Colorado National Monument, a major unconformity exists between the Precambrian rocks (1.4 bya) and the Triassic Chinle Formation (1200 mya). The hiatus represented by this gap is:
1200 million years
The oldest rocks in Colorado are approximately ____ old
2.7 billion years
Which of the following is not a physiographic province in Colorado?
Cascade Mountains
Grand Junction is located in the .... Physiographic Province
Colorado Plateau
The last time the area now known as Colorado was flooded by ocean water
Cretaceous Period (Phase 4)
From the surface of the Earth down to the center, the Earth's internal zones are:
Crust, mantle, outer core, inner core
Numerous paleogeographic maps were shown during Prof. Cole's lectures. The geologist-artist who constructed these maps is..
Dr. Ron Blakey, recently from Northern Arizona University
Denver is located on the wester edge of the ..... Physiographic Province
Great Plains
The energy that drives the "tectonic engine" (plate movement) comes from:
Heat, which comes from radioactive decay of Uranium, thorium, and potassium, plus heat left over from the earth's formation
Which of the following statements pertains to the concept of superposition?
In a stack of undeformed sedimentary rocks, the oldest layer will be at the bottom
Regarding quantitive (numerical) age dates for Precambrian igneous rocks in Colorado, which of the following statements is correct?
Most dates cluster around 250, 130, and 75 million years ago
The plate-tectonic formation of the supercontinent called ... was the trigger for the creation of the Ancestral Rocky Mountains
Pangea
When did glaciation significantly impact Colorado?
Phase 6
Argon-40 is the radioactive decay product (daughter) of...
Potassium 40
You are driving on Interstate 70 over the Front Range near the Eisenhower Tunnel and your car sputters to a stop. As you wait for help to arrive, you start looking at the rocks in a nearby road cut. Which of the following will you observe?
Precambrian metamorphic and igneous rocks
The giant Phase 6 "crack" (divergent plate boundary) in Colorado is called the:
Rio Grande Rift
The orogeny took place in Utah, Arizona, and Nevada.
Sevier
Which statement summarizes the occurrence of Silurian sedimentary rocks?
Silurian sedimentary rocks are only found in diatremes of north-central Colorado
The largest physiographic province in Colorado is:
Southern Rock Mountain
These two sedimentary rock units are Precambrian in age
The Unita Mountain and Uncompahgre Groups
Which of the following statements best summarizes Colorado's history during Phase 2 (Cambrian-Mississippian periods)
The seas came in and the seas went out
Which statement is false?
There are three types of strain (deformation): elastic, plastic, spastic
Which of the following statements describes the velocity at which tectonic plates move?
They move about the same rate that your fingernails grow (inches per year)
If sedimentary rocks are deformed into an "Arch"-shaped fold (cross-sectional view) the structure is called:
an anticline
If sedimentary rocks are deformed into a "Sag"-shaped fold (cross-sectional view) the structure is called:
an syncline
Igneous rock type (magma type) that is created by the partial melting of oceanic crust in a subduction zone
andesite
This partially molten layer of igneous rock underlies the lithosphere
asthenosphere
The assigned video was produced by geologists and graphic artists
at the University of Colorado, Boulder
Which of the following is not a basic type of heat transfer?
gravity
The earth's core is thought to be composed of mainly.....
iron and nickel
If we could use a time machine to visit Grand Junction area during late Phase 3 (Jurassic) when the Wingate Sandstone was being deposited, we would see:
large migrating sand dunes
By definition, the rocks below a nonconformity consist of:
metamorphic and/or igneous rocks
A spectacular fold called a ..... can be seen in the sedimentary rocks along the front of the Colorado National Monument.
monocline
The term used to define a period of mountain building in the geological past:
orogeny
New oceanic crust is created here.
spreading ridges at divergent plate boundaries
A normal fault is defined by:
the foot-wall block moving up with respect to the hanging-wall block
The time required for one-half of the radioactive parent atoms to decay to their stable daughter atoms is called:
the half life
A reverse fault is defined by:
the hanging wall block moving up with respect to the foot wall block
When an igneous rock is dated by the uranium-lead or other radiometric method the number (date) that is obtained indicates:
when magma cooled and solidified into rock
If an igneous dike crosscuts a sandstone bed, the dike is .... the sandstone
younger than