Stratigraphy and fossils Figure 8.2 (page 201) Go to next slide to begin

Stratigraphy and fossils

Figure 8.2 (page 201)Go to next slide to begin

Sedimentation inlake or sea

Sedimentation inlake or sea

Sediments are deposited in horizontal layers and slowly change into rock.

Younger

Older

Younger

Older

If left undisturbed, the youngest layers remain above the oldest.

Key Figure 8.3 (page 202)Go to next slide to begin


Outcrop A Outcrop B

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II

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Outcrop A Outcrop B

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II

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Outcrop A Outcrop B

III

II

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Outcrop A Outcrop B

III

II

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Some of the fossils found inoutcrop A are the same as fossils found in outcrop B, some distance away.

Outcrop A Outcrop B

III

II

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Layers with the same fossils are the same age.

Outcrop A Outcrop B

III

II

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Layers with the same fossils are the same age.

Stratigraphicsuccession

A composite of the two outcrops.

Younger rocks

Older rocks

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II

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Select the principle of relative dating that is most useful in correlating rock strata among widely separated areas (regionally).

A. SuperpositionB. Faunal successionC. Cross-cutting relationshipsD. Original horizontality


Select the principle of relative dating that is most useful in correlating rock strata among widely separated areas (regionally).

A. Superposition

B. Faunal successionC. Cross-cutting relationshipsD. Original horizontality


Who established the Principle of Faunal Succession?

A. James HuttonB. Nicolaus StenoC. William SmithD. Harry Hess


Who established the Principle of Faunal Succession?

A. James HuttonB. Nicolaus Steno

C. William SmithD. Harry Hess


True or False: The Principle of Faunal Succession only applies to a single region, and it cannot be used to correlate stratigraphic sequences on different continents.

A. TrueB. False


True or False: The Principle of Faunal Succession only applies to a single region, and it cannot be used to correlate stratigraphic sequences on different continents.

A. True

B. False


Select the kind(s) of geologic data that can be used to globally correlate strata.

A. Fossil dataB. Paleomagnetic dataC. Seismic dataD. Radioactive isotope dataE. All of the above


Select the kind(s) of geologic data that can be used to globally correlate strata.

A. Fossil dataB. Paleomagnetic dataC. Seismic dataD. Radioactive isotope data

E. All of the above


The radioactive decay of rubidium to strontium

Figure 8.11 (page 209)Go to next slide to begin

Rubidium-87 nucleus

Neutrons Protons

Electron

Rubidium-87 nucleus

Neutrons Protons

Electron

A neutron decays, ejecting an electron…

Rubidium-87 nucleus

Neutrons Protons

Electron

Strontium-87 nucleus


Rubidium-87 nucleus

Neutrons Protons

Electron


Strontium-87 nucleus

…and producing a proton,which changes the atom.

What do all isotopes of any given element have in common?

A. Number of protonsB. Number of neutronsC. Combined number of protons and neutronsD. All of the above


What do all isotopes of any given element have in common?

A. Number of protonsB. Number of neutronsC. Combined number of protons and neutronsD. All of the above


True or False: The half-life of a radioactive isotope does not vary with changes in temperature and pressure.

A. TrueB. False


True or False: The half-life of a radioactive isotope does not vary with changes in temperature and pressure.

A. TrueB. False


A mineral forms and initially incorporates only the parent atoms of a radioactive isotope and no daughter atoms. The parent has a half-life of 5000 years. How long before the parent to daughter ratio is 1:3?

A. 5000 yearsB. 10,000 yearsC. 15,000 yearsD. 20,000 years


A mineral forms and initially incorporates only the parent atoms of a radioactive isotope and no daughter atoms. The parent has a half-life of 5000 years. How long before the parent to daughter ratio is 1:3?

A. 5000 years

B. 10,000 yearsC. 15,000 yearsD. 20,000 years


The principles of Original Horizontality and Superposition allow for ____________ dates to be determined.

A. AbsoluteB. NumericC. RelativeD. Radiogenic

Original Horizontality

The principles of Original Horizontality and Superposition allow for ____________ dates to be determined.

A. AbsoluteB. Numeric

C. RelativeD. Radiogenic


In an undisturbed sequence of sedimentary rocks where do the oldest rock strata occur?

A. At the top of the sequenceB. At the bottom of the sequenceC. It depends on the depositional environment


In an undisturbed sequence of sedimentary rocks where do the oldest rock strata occur?

A. At the top of the sequence

B. At the bottom of the sequenceC. It depends on the depositional environment


True or False: Sediments can remain unlithified for millions of years before becoming lithified sedimentary rocks.

A. TrueB. False

Sedimentary bedding

True or False: Sediments can remain unlithified for millions of years before becoming lithified sedimentary rocks.

A. TrueB. False

Sedimentary bedding

What kind of unconformity occurs between two horizontal sedimentary beds?

A. A disconformityB. A nonconformityC. An angular unconformity

Sedimentary bedding

What kind of unconformity occurs between two horizontal sedimentary beds?

A. A disconformityB. A nonconformityC. An angular unconformity

Sedimentary bedding

What is the approximate maximum age a piece of charcoal can be in order to determine its date using the carbon-14 method of dating?

A. 4,000 yearsB. 70,000 yearsC. 1,000,000 yearsD. 50,000,000 years

Wasatch Fault

What is the approximate maximum age a piece of charcoal can be in order to determine its date using the carbon-14 method of dating?

A. 4,000 years

B. 70,000 yearsC. 1,000,000 yearsD. 50,000,000 years

Wasatch Fault

Transgression/Regression

When sea-levels fall, the sedimentary record of depositions along the coast records this change, which is described as:

A. a transgressionB. a turbidity currentC. global warmingD. a regression


When sea-levels fall, the sedimentary record of depositions along the coast records this change, which is described as:

A. a transgressionB. a turbidity currentC. global warming

D. a regression


When a transgression is observed in the sedimentary record, it is interpreted from a shift to off-shore marine facies as a result of:

A. decreasing global temperaturesB. sea-level riseC. subductionD. sea-level fall


When a transgression is observed in the sedimentary record, it is interpreted from a shift to off-shore marine facies as a result of:

A. decreasing global temperatures

B. sea-level riseC. subductionD. sea-level fall


While hiking in the Grand Canyon of northern Arizona, you stop and observe an outcrop that exposes three different sedimentary rock types. On the bottom is a layer of shale, which is overlain by a layer of limestone, which is in turn overlain by a layer of sandstone. This stratigraphy sequence indicates that a _________ or a _________ in sea-level occurred in this location in the past.

A. transgression; fallB. transgression; riseC. regression; fallD. regression; rise


While hiking in the Grand Canyon of northern Arizona, you stop and observe an outcrop that exposes three different sedimentary rock types. On the bottom is a layer of shale, which is overlain by a layer of limestone, which is in turn overlain by a layer of sandstone. This stratigraphy sequence indicates that a _________ or a _________ in sea-level occurred in this location in the past.

A. transgression; fallB. transgression; rise

C. regression; fallD. regression; rise


What trend would you expect to find in sediments accumulating in any single location along the coast during a sea-level rise?

A. the sediment size should decrease as you look up-sectionB. the sediment should become better sorted as you look up-sectionC. the sediment should become more rounded as you look up-sectionD. all of theseE. none of these


What trend would you expect to find in sediments accumulating in any single location along the coast during a sea-level rise?

A. the sediment size should decrease as you look up-sectionB. the sediment should become better sorted as you look up-sectionC. the sediment should become more rounded as you look up-section

D. all of theseE. none of these


Changes in global sea-levels are most often caused by shifts in climate. For example, a transgression would be caused by an increase in the melting rate of polar ice caps, which is in turn driven by:

A. a reduced greenhouse effectB. an increase in atmospheric dustC. an increase in global temperaturesD. a reduction in atmospheric carbon dioxide


Changes in global sea-levels are most often caused by shifts in climate. For example, a transgression would be caused by an increase in the melting rate of polar ice caps, which is in turn driven by:

A. a reduced greenhouse effectB. an increase in atmospheric dust

C. an increase in global temperaturesD. a reduction in atmospheric carbon dioxide


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Stratigraphy and fossils Figure 8.2 (page 201) Go to next slide to begin