Ch. 4

which numbered layer in this photograph represents the oldest layer?

This photograph shows an upper unit with fragments and a lower unit with tilted layers. Which of the following statements is true? -the upper unit is younger because it is on top -the upper unit is younger because it contains pieces of the underlying unit -the lower unit is older because it was tilted and eroded before deposition of the upper unit

How would we use isotopic ages to infer the ages of the upper and lower unit in this diagram?

Of the following numbered units, which is the youngest?

Of the following numbered units, which is the oldest?

What would fossil ages from the geologic timescale tell us about the age of this unconformity? -The unconformity is younger than the fossil ages on the tilted bed. -The unconformity is older than the fossil ages in layers above the unconformity. -The amount of time represented by the unconformity can be approximately bracketed by the ages of the fossils above and below.

which of the numbered units is the oldest?

What type of feature is represented by the boundary between geologic units 2 and 3?

The geologic relationships in this figure indicate that the lava flow:

If a rock started with 1,000 atoms of a parent but now contains 250 atoms, how many half lives have passed?

This photograph shows light-colored granite and darker diorite (both igneous rocks). Which of the following statements is true?

What is the youngest event represented in this block diagram?

The fossil fern in this photograph probably indicate that the rock was deposited:

What factors are the most critical in determining whether a fossil is preserved?

How did an oxygen-rich atmosphere develop from a carbon dioxide-rich atmosphere?

James Hutton inferred that the rocks below the contact at Siccar Point were vertical gray sandstone and shale and the rocks above were gently dipping red sandstone and conglomerate. Therefore, the histories of these rocks:

Which of the following features look like fossils but are not?

Who came up with the concept that geologic processes operating at present are the same processes that operated in the past?

This figure shows the main subdivisions of the geologic timescale. Which of these is the Cenozoic?

Which of the following is the earliest (oldest) chapter of geologic time?

Upon what basis were the upper and lower boundaries of the Mesozoic Era defined?

The geologic timescale details and divides geologic time based upon:

Which of the following is NOT accurately dated at between 4 and 4.6 billion years old?

What were some of the earliest forms of life on Earth?

What time period is represented by this scene?

Which principle is used to determine the age of rocks by ordering them from oldest on the bottom to the youngest on the top?

Missing geologic time caused by erosion is called a (an):

The term half life represents the time it takes:

What was the Cambrian explosion?

What is a possible cause of the extinction event called the Great Dying?

Early Earth would have been inhospitable to many life forms of today because:

What marks the boundary between the Mesozoic and the Cenozoic (called the K-P boundary)? -the extinction of the dinosaurs -the start of a rise to dominance of mammals -the meteorite impact in Mexico