Geologic time

Ace your homework & exams now with Quizwiz!

The age estimate for point A in the diagram above is ______ million years

1.6

A rock formed with 1,000 atoms of a radioactive parent element, but only contains 250 radioactive parent atoms today. If the half-life is 1,000,000 years, how old is the rock?

2,000,000 years

The age estimate for point C in the diagram above is ______ million years

245

The age estimate for point E in the diagram above is ______ million years

2500

Atoms of AA decay to atoms of BB with a half-life of 100,000 years. If there are 20,000 atoms of AA to begin with (and 0 atoms of BB), how long will it take for there to be 2,500 atoms of AA?

300,000 years

The age estimate for point D in the diagram above is ______ million years

570

The age estimate for point B in the diagram above is ______ million years

65

Which of the following units is the youngest?

A (above x)

Human beings evolved during which geologic era?

Cenozoic

Mammals became abundant during the ________Era?

Cenozoic

Which of the following units is the oldest?

D (below x)

The Paleozoic does not include the

Jurassic

The _________ was an era dominated by the dinosaurs

Mesoic

Large reptiles became abundant during the ________Era?

Mesozoic

In the past there were (more or less) atoms of radioactive Uranium?

More

Therefore, there was (more or less) heat produced in the crust in the past:

More

Land plants appeared during the ________Era?

Paleozoic

Which of the following represents the longest time period

Precambrian

Which of the following statements regarding radiometric dating is false?

Sedimentary rocks can be dated more easily than igneous rocks

Who is credited with developing the principle of faunal succession?

William "Strata" Smith

A nonconformity is _________

a gap in the geologic record bounded below by metamorphic or igneous rocks and bounded above by sedimentary rocks

Radiometric age is often referred to as __________ age

absolute

A disconformity is ___________

an erosional surface between horizontal sedimentary rocks

The horizontal line labeled X-X' is a(n) ________

angular unconformity

What is the name for an erosion surface that separates two sets of sedimentary layers with non-parallel bedding planes?

angular unconformity

Radiometric dating is possible if a rock contains a measurable amount of ________ .

both parent and daughter isotopes

Which of the following isotopes is most useful for dating very young wood and charcoal?

carbon-14

Which of the following radioactive isotopes has the shortest half-life?

carbon-14

Which of the following radioactive isotopes is most useful for dating a very young sample (<20,000 years) of wood

carbon-14

Which of the following will not make a fossil?

decomposed organic material

Which of the following occurred most recently?

deposition of unit A

Which of the following happened most recently?

deposition of unit B (before x)

The boundaries between _______ seem to coincide with major changes in the life forms present on Earth.

eras

Most periods in the geologic time scale are named for _______

geographic localities

The most common fossils in rocks of the last 500 million years are _______

invertebrate shells

Uranium-238 decays to which of the following daughter isotopes?

lead-206

We cannot accurately measure time in years with stratigraphy for several reasons. Which of the following is false

many sedimentary rocks contain fossils that have not been identified

The study of faunal succession allows ___________

matching of similarly-aged rocks from different outcrops

An undeformed sedimentary layer is __________ than the layer above and _______ than the layer below

older --- younger

What scientific avenue of investigation gave scientists the best estimate of the age of the Earth?

radiometric dating

Fossils are most common in which rock types?

sedimentary

Radiometric dating is least useful for ___________ rocks

sedimentary

Radiometric dating is least useful for dating _________ rocks.

sedimentary

The principal of original horizontality states that ________

sediments are deposited as essentially horizontal layers

Which of the following is used by geologists to determine the relative ages in a rock sequence?

stratigraphy fossils cross-cutting relationships

Which of the following could be used to tell if a rock layer was right side up or up side down__________

symmetrical ripple marks

Which of the following statements is true?

the relative ages of the granite and unit B cannot be determined from the information given

A Potassium-Argon (K-Ar) age measures _________

the time since last cooling below the gas retention temperature - Argon is the gas

George Geologist finds that unit F contains eroded pieces of unit G. Which of the following statements is true?

unit B is younger than the granite

Which of the following statements is false?

unit C is younger than unit A

The radon environmental hazard is associated with the radioactive decay of ______ .

uranium-238

Which of the following radioactive isotopes has the longest half-life?

uranium-238

A stratigraphic sequence is a vertical set of strate

used as a chronological record of the geologic history of a region


Related study sets

C482 Software 1: Oracle Certified Associate Java SE 8

View Set

Patho: Unit 7 GU and Reproductive function

View Set

Ch 5 Comp Methods: Bracketing Methods

View Set

Ch. 7 ~ Skeletal System: Skull Superior View

View Set

Art Chapter 2: How Should We Look at Art?

View Set