Exam 3: How Old Is Old the Rock Record and Geologic Time

Why is the half-life of a radioactive element important in considering the choice of a method to be used for determining the radiometric age of a mineral or rock?

In the photo of the sedimentary sequence of the Grand Canyon shown below,the ______ is/are the youngest sedimentary strata.

The time needed for half of the parent atoms of a radioactive substance to decay into daughter atoms is termed the_________________ .

For the block diagram below,what type of unconformity is labeled as 2?

Some people believe that the age of Earth is very young.What evidence supports the conclusion of scientists that Earth is much older,approximately 4.56 billion years?

The contact beneath the Tapeats Sandstone and the underlying Grand Canyon Supergroup is an example of a(n)

A(n)______is a surface of erosion between two groups of sedimentary rocks in which the orientation of the older strata below are at an angle to younger strata above.

The principle of stratigraphic superposition tells us that _____.

For the stratigraphic section of the Grand Canyon depicted in the photograph below,which rock unit is older?

For the block diagram below,what type of unconformity is labeled as 3?

Nineteenth century geologists tried to estimate the absolute age of rock strata by calculating how long it would take to deposit a stratigraphic sequence of a given thickness.What was wrong with this approach?

For the figure below what types of unconformities are represented by the contacts marked as 1,2 and 3.?

Strata in which the layers of sediment have been deposited one on top of another,in sequence with no significant gaps in time,are said to be ______.

When we see sedimentary rock units that are twisted or tilted,we know that some force must have disturbed the strata after they were deposited.The principle upon which we base this inference is the principle of _____.

In the block diagram below,the contact between rock unit 4 and the underlying intrusion B is an example of a(n)

For the block diagram below,which of the following statements is(are)true?

In the block diagram below,the contact between rock unit 4 and the underlying rock unit 3 is an example of a(n)

How did William Smith's discovery of faunal succession lead to the correlation of rock strata and eventually the geologic column?

What principle would allow you to determine the relative ages of different parts of the stratigraphy of this section of the Grand Canyon?

An isotope that is undergoing radioactive decay is called a parent,and an isotope that forms as a result of radioactive decay is called a _____.