Ch 8, The Rock Record Re Flashcard

Front

The time required for half of a sample of a radioactive isotope to break down by radioactive decay to form a daughter isotope is called what?

Back

half-life

Front

The trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock

Back

fossil

Front

Which of the following is 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? Options: radiometric dating, uniformitarionism, law of superposition, paleontology

Back

radiometric dating

Front

A principle that geologic processes that occurred in the past can be explained by current geologic processes is called...

Back

uniformitarianism

Front

The age of an object in relation to the ages of other objects is known as what?

Back

relative age

Front

What is the scientific study of fossils called?

Back

paleontology

Front

The principle that a sedimentary rock layer is older than the layers above it and younger than the layers below it if the layers are not disturbed is called ...

Back

law of superposition

Front

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 what?

Back

unconformity

Front

The numeric age of an object or event, often stated in years before the present, as established by an absolute-dating process such as radiometric dating is known as what?

Back

absolute age

Front

What is a fossil that is used to establish the age of a rock layer because the fossil is distinct, abundant, and widespread and the species that formed that fossil existed for only a short span of geologic time?

Back

index fossil