Chp 12 Questions

A very young geologic event.

A radioscope with a short half-life should be used to date:

Assessments of time needed to allow for evolution as recorded in rocks; Calculations of the time needed for Earth to cool; Calculations of the rate of delivery of salt to the sea; Estimates of sediment accumulation over tim

Early critical thinkers estimated Earth's age using:

4.6 Billion

Earth formed approximately how many years ago?

Unconformities cut across pre-existing strata.

Explain how the principle of cross-cutting relationships is related to the principle of unconformities.

Erosion

If a layer of rock appears to be cut into and filled by the overlying layer, what has likely occurred?

human chronology, climate change, and environmental processes

In what areas has the radiocarbon dating method advanced our understanding?

Evidence that Earth's age is approximately 4.6 billion years

Moon rocks are:

Western Interior Seaway

Name the region where the following even took place: A warm climate caused sea level to rise and advance from the south all the way into Canada. This warm, shallow sea developed after the breakup of Pangaea.

open-system behavior

One problem with radiometric dating is:

Estimating the age of a sample using radioisotopes

Radiometric dating is the process of:

Determining the sequence of events in a period of geologic history.

Relative dating is the process of:

Deposition, erosion, deformation, faulting, and intrusion.

The five fundamental geologic events described by stratigraphic principles are:

Highest layers in an undeformed sequence are the youngest; Lowest layers in an undeformed sequence are the oldest; Older rock units typically are found at the base of a sequence of rocks; A rock layer lying above another must be the younger of the two.

The principle of superposition states that

Has a long half-life

To date a very old rock, a geologist should use an isotope that:

True

TorF: A continent may rise related to plate convergence and may fall related to rifting.

True

TorF: At Siccar Point, shale from the Silurian period (turned vertically) is overlain by younger sandstone (known as the "old red sandstone") from the Devonian period.

False

TorF: Calculations of Earth's age as 4.6 billion years old are inconsistent with the ages independently determined from meteorites and lunar rocks.

False

TorF: Each radioisotope decays at a unique, unfixed rate.

False

TorF: If a sample to be dated is several hundred million years old, it is appropriate to date it using a radioisotope with a half-life of a few thousand years.

False

TorF: If the daughter isotopes have left the sample, the calculated age will be too old.

False

TorF: James Ussher was the first person to apply the stratigraphic principles as a relative dating tool.

True

TorF: Sedimentary rocks can be analyzed to provide a history of changing life on Earth.

True

TorF: The oldest Moon rocks are from lunar highlands composed of old crust.

True

TorF: The presence of an igneous dike indicates intrusion.

Primary radioisotopes have longer half-lives than cosmogenic radioisotopes.

Typically

The idea that the age of the universe can be measured in billions of years

What best describes the concept of deep time?

They are no longer free to move about.

What happens to the movement of atoms when molten rock cools and crystallizes?

Broken, displaced and folded layers

What indicates that faulting and deformation have occurred?

mass spectrometer

What instrument do scientists to use to measure the abundance of isotopes in a sample?

Continental freeboard

What is the relative difference between a continent and the sea level referred to as?

Determining the age of moon rocks and meteorites, measuring old rocks and minerals and the amount of lead isotopes created by radioactive decay.

What techniques are used to determine when the Earth was formed?

Bible

What used to be a common source of interpretation of Earth's age by many biblical scholars?

Cross-cutting relationships

When an intrusion invades the crust, its relative position in a sequence of geologic events is determined using the principle of:

high-energy particles from the Sun interact with nitrogen in the air.

When is the radioisotope carbon-14 formed in the atmosphere?

Carbon-14

Which method would a geologist use to date a fossil bone fragment of a mammoth?

Both the oldest rocks were probably destroyed in the molten phase of Earth's early history and processes of the rock cycle have recycled the crust and destroyed direct evidence of Earth's early history.

Which of the following are reasons why efforts to identify rocks from the time of Earth's origin have failed?

The unstable nucleus of an atom spontaneously emits radiation and a subatomic particle.

Which process occurs during radioactive decay?

They are the wrong size

Why are daughter isotopes often not incorporated into the crystalline structure?

They followed the social order of time, the logic of other theologians, and they didn't threaten the authority of the church.

Why were Bishop James Ussher's concepts of Earth's age widely accepted?

His use of the principle of fossil succession.

William "Strata" Smith is known for:

Radioisotopes

Within most igneous, sedimentary, and metamorphic rocks are radioactive atoms called

short-lived

Young geologic samples should be dated with ______ radioisotopes.

Siccar Point

is now one of the most famous sites in the history of geology, known as Hutton's Unconformity.