Climate History
A long cylinder of ice obtained from drilling through ice caps or ice sheets; used to study past climates is called ______?
ice core
Describe the law of superposition
A sedimentary rock layer in its original position is older than the layers above it and younger than the layers below it.
Trace fossils always form in soft sediment. Describe two kinds of trace fossils.
tracks and burrow
A method of determining the absolute age of an object by comparing the relative percentages of a radioactive parent isotope and a stable daughter isotope is called _____?
absolute dating
A principle that geologic processes that occurred in the past can be explained by current geologic processes is called ______?
uniformitarianism
Florida State University has a large collection of ice cores taken from the Antarctic. What can scientists learn by studying these ice cores?
history of Earth's climate
Any method of determining whether an event or object is older or younger than other events or objects is called _____?
relative dating
Imagine that you are searching for fossils. Which of the following is the best place to visit for finding fossils?
Petrified Forest National Park, Arizona
Andrew wants to determine a more accurate age of a shell that is known to be between 10,000 and 30,000 years old. Which method would be most useful for finding a more precise age of the shell?
radiocarbon dating
A break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time is called _____?
unconformity
Weather is not the same thing as climate. What is the key difference between the two concepts?
length of time each are measured
How does the law of superposition apply to sedimentary rocks?
sedimentary rock forms in layers; rock layer is older than the layer above and younger than layer below
A fossilized structure, such as a footprint or a coprolite, that formed in sedimentary rock by animal activity on or within soft sediment is called _____?
trace fossil
When a rock formed, it contained the parent isotope, uranium-238, but it did not contain the daughter isotope. Describe how this rock would change over time.
The amount of uranium-238 would decrease, and the amount of lead-206 would increase.
An ordered arrangement of rock layers that is based on the relative ages of the rocks and in which the oldest rocks are at the bottom is called _____?
geologic column
The weather conditions in an area over a long period of time is called _____?
climate
How are sedimentary rock layers deposited?
in horizontal layers
Name 5 ways that organisms can be preserved as fossils.
amber, asphalt, buried in rock, frozen, petrified
When a rock first formed, it contained 8 milligrams of potassium-40. How much potassium-40 would remain after three half-lives?
1 milligram
A principle that states that younger rocks lie above older rocks if the layers have note been disturbed is called ____?
superposition
Name 3 materials that show how Earth's climate has changed over time.
trees, sea-floor sediment, ice cores
Name 5 ways a rock layer can be disturbed.
fault, intrusion, folding, tilting, unconformity
Scientists recently discovered the fossils of a dinosaur adapted for a warm climate frozen in the Antarctic ice. Based on this evidence, what can you conclude about Earth’s climate?
change from warmer to colder climate; fossils are evidence of climate change
What method has the most useful time range of 100,000 to a few billion years old?
potassium-argon dating
How old is Earth?
4.6 billion years