Deck 6: Correlation and Dating of the Rock Record

Question 1

Select the characteristic below that is NOT consistent with an index or guide fossil.

A) The fossil is very rare in the stratigraphic record.
B) The fossil is easily distinguished from other taxa.
C) The fossil is geographically widespread.
D) The fossil occurs in many kinds of sedimentary rock and in many places.

Answer 1

A

Question 2

Uppermost ___________ rocks document an episode of widespread extinction and expansion of glaciers near the south pole that we know was related to that extinction.

A) Cambrian
B) Ordovician
C) Silurian
D) Devonian

Answer 2

B

Question 3

One of the problems with trying to compute the absolute age of Earth based on rates of accumulation of sediment is that

A) removal of salts by evaporate deposition has approximately balanced the addition of salts by rivers and other sources.
B) radioactive decay and its heat contribution to Earth's heat need to be taken into account.
C) the salinity of the world ocean may not have changed much since early in Earth's history.
D) the stratigraphic record is full of gaps and unconformities.

Answer 3

D

Question 4

A(n) __________ includes all strata in the world that were deposited during a particular interval of time called an Epoch.

A) epoch
B) stage
C) erathem
D) series

Question 5

Select the method below that is NOT a legitimate way that an isotope undergoes decay from parent to daughter isotope.

A) Loss of an alpha particle
B) Capture of an alpha particle
C) Loss of a beta particle
D) Capture of a beta particle

Question 6

__________ form the basis for all magnetic stratigraphy.

A) Outpourings of iron-rich lava and magma
B) Reversals of Earth's magnetic field
C) Small grains of iron-bearing minerals that settle from water to become parts of sedimentary rocks
D) Minerals that crystallize from lava or magma

Question 7

The boundary between two chronostratigraphic units, for example, Ordovician and Silurian, is formally defined at a single locality known as a

A) stratigraphic range.
B) geochronologic unit.
C) boundary stratotype.
D) time-rock unit.

Question 8

A time-rock unit is the same thing as a __________ unit.

A) chronologic
B) chronostratigraphic
C) biostratigraphic
D) lithostratigraphic

Question 9

If after three half-lives, a mineral crystal that originally contained 80 atoms of a common, radioactive isotope of uranium would contain how many atoms of the original isotope?

A) 40
B) 20
C) 10
D) 5

Question 10

Correlation of local stratigraphic sections measured along the walls of the Grand Canyon shows that the lower part of the Muav Limestone changes laterally into the

A) upper part of the Bright Angel Shale.
B) upper part of the Tapeats Sandstone.
C) upper part of the Muav Limestone.
D) lower part of the Tapeats Sandstone.

Question 11

In 1879, __________ proposed that a system be erected between Cambrian and Silurian.

A) Charles Lapworth
B) Adam Sedgwick
C) Charles Lyell
D) Omalius d'Halloy

Question 12

A __________ displays a vertical sequence of rock layers in a local outcrop or other rock exposure, but which does NOT necessarily define a stratigraphic unit.

A) boundary stratotype
B) type section
C) stratigraphic section
D) time-rock unit

Question 13

A __________ is a polarity time-rock unit.

A) pole
B) zone
C) chron
D) group

Question 14

Potassium-argon and argon-argon dating techniques are used on

A) some minerals that form in igneous and metamorphic rocks.
B) igneous, metamorphic, and even in a few sedimentary rocks older than about 10 million years.
C) objects of biological origin, such as bones, teeth, and pieces of wood.
D) reef-building corals and certain other fossils with these elements within them.

Question 15

Select the description below that is NOT some type of biozone.

A) A body of rock defined by the range of a single taxon
B) A body of rock having a lower boundary defined by the lowermost or uppermost occurrence of one taxon and an upper boundary defined by the lowermost or uppermost occurrence of another taxon
C) A body of rock with lower and upper boundaries based on the ranges of one or more taxa, usually species, in the stratigraphic record
D) A body of rock defined by the absence of taxa

Question 16

In a joint paper (1835), British geologists Adam Sedgwick and Roderick Murchison named the __________ systems, based principally upon studies in Wales.

A) Precambrian and Cambrian
B) Cambrian and Devonian
C) Cambrian and Silurian
D) Precambrian and Silurian

Question 17

In 1839, the Silurian System was defined primarily on the basis of

A) the nature of sedimentary rocks lying directly upon ancient crystalline rocks.
B) seven distinct fossil mammalian faunas of the Paris Basin.
C) expansion of glaciers at the south pole, which was related to a mass extinction.
D) trilobites, brachiopods, and crinoids, and as well as corals that formed small reefs.

Question 18

__________ was the first to conclude that species have become extinct over the course of Earth's history.

A) Charles Darwin
B) George Cuvier
C) James Hutton
D) Charles Lyell

Question 19

A regression might result in a sandy beach facies being deposited on top of a __________ facies.

A) muddy lagoon
B) meandering stream
C) muddy offshore
D) gravelly alluvial fan

Question 20

Among those listed below, __________ is the smaller lithostratigraphic unit.

A) group
B) supergroup
C) member
D) formation

Question 21

In a typical cross- section showing facies in a transgression-regression, the place where the facies boundary meets the line of correlation is called

A) the "moment" of maximum regression.
B) the "moment" of maximum transgression.
C) the level of the unconformity.
D) an event or marker bed.

Question 22

For alpha decay to cause a loss in mass, such as that in the uranium 238 conversion to thorium 234, what must the atomic weight of the alpha particle be?

A) 0
B) 2
C) 4
D) 6

Question 23

Select the layer below that is NOT a good marker bed for temporal correlation.

A) Volcanic ash bed
B) Dark and light bands in some evaporate deposits
C) Iridium-enriched layers
D) A bed of conglomerate lying on a transgressive surface

Question 24

Preservation of deposits resulting from instantaneous events preserved within sedimentary layers is the basis for correlation in

A) event stratigraphy.
B) biostratigraphy.
C) isotope stratigraphy.
D) lithostratigraphy.

Question 25

__________ provides a means for determining how long an object has been exposed at Earth's surface.

A) Radiocarbon dating
B) Cosmogenic dating
C) Thermoluminescensce dating
D) Optical dating

Question 26

The shortest of the Milankovitch cycles of change in Earth's astronomical movements is called

A) precession.
B) obliquity.
C) eccentricity.
D) feedback.

Question 27

The approximate half-life of radioactive decay from rubidium 87 to strontium 87 is __________ billion years.

A) 0.7
B) 1.3
C) 4.6
D) 48.8

Question 28

The change over time in the ratio of two isotopes of __________ in the world ocean is the basis for much of stable isotope stratigraphy.

A) thorium
B) carbon
C) strontium
D) uranium

Question 29

Global changes of sea level are the same as

A) sequences.
B) eustatic changes.
C) seismic stratigraphy.
D) marker beds.

Question 30

__________ is the method used to divide much of the stratigraphic record into units called __________, which are large bodies of marine sediment bounded by unconformities resulting from relatively sudden drops in sea level.

A) Seismic stratigraphy; eustatic changes
B) Global unconformities; eustatic changes
C) Seismic stratigraphy; sequences
D) Global unconformities; sequences