Freeman-Lynde GLY116 Sedimentary Rocks & Stratigraphic Terms

Walther's Law only applies to a section without unconformities.
Walther's Law states that facies adjacent to one another in a continuous vertical sequence are adjacent to one another laterally as well.
The concept of "Facies" refers to the lateral variation of environments of deposition within a time-rock unit.
The concept of the FORMATION is an outgrowth of the time-rock concept that indicates the gradation of environments of deposition during a given time.
What does the concept of FACIES state?
- A. Facies is the lateral gradation of sedimentary units having a distinctive set of physical, chemical & biological attributes due to gradation in environments of deposition during a given time.
- B. Facies adjacent to one another in a continuous vertical sequence are adjacent to one another laterally as well.
- C. Facies adjacent to one another across an unconformity are adjacent to one another laterally as well.
- C. Facies adjacent to one another across an unconformity are not necessarily adjacent to one another laterally.
- D. all of these D. both A. & B. E. none of these
What does Walther's Law state?
- A. Facies is the lateral gradation of sedimentary units having a distinctive set of physical, chemical & biological attributes due to gradation in environments of deposition during a given time.
- B. Facies adjacent to one another in a continuous vertical sequence are adjacent to one another laterally as well.
- C. Facies adjacent to one another across an unconformity are adjacent to one another laterally as well.
- D. both A. & B. E. none of these
In the diagram to the left below, which of the following statements based on Walther's Law is true?
- A. Both B. & C.
- B. A freshwater lake was immediately adjacent to a beach.
- C. The ocean environments depositing mud & carbonate sediments were immediately adjacent.
- D. A freshwater lake was immediately adjacent to the ocean environment depositing carbonate.
- E. A freshwater lake was immediately adjacent to the ocean environment depositing mud.
- A. An alluvial fan was immediately adjacent to the ocean.
- B. Conglomerate & shale depositing environments were immediately adjacent.
- C. Conglomerate & sandstone depositing environments were immediately adjacent on an alluvial fan.
- D. Limestone & shale depositing environments were immediately adjacent in a marine environment.
- E. Both C. & D.
The concept of _________________________________ refers to the lateral gradation of sedimentary units having distinctive physical, chemical & biological attributes due to gradation in environments of deposition during a given time.
__________________________ is an idea that is an outgrowth of the time-rock concept that indicates the gradation of environments of deposition during a given time.
2
A regression/transgression ALWAYS results from a eustatic rise/fall in sea level.
Eustatic sealevel rises always result in marine transgressions.
Eustatic sealevel rises usually result in marine transgressions, but not always.
During a transgression the shoreline moves seaward.
A transgression ALWAYS indicates a movement of the shoreline landward.
Eustatic changes in sealevel are caused by uplift or subsidence, OR changes in sedimentation rate, OR both.
Eustatic changes in sealevel are caused by continental glaciation & seafloor spreading rate changes.
Eustatic changes in sealevel only result from continental glaciation.
Relative changes in sealevel are caused ONLY by continental glaciation & seafloor spreading rate changes.
Which of the following situations would result in a marine transgression/REGRESSION?
- A. slow subsidence during a fast eustatic sea level lowering
- B. fast subsidence during a slow eustatic sea level lowering
- D. fast sedimentation during a slow eustatic sea level rise
- A. slow subsidence during a fast eustatic sea level lowering
- B. slow subsidence during a fast eustatic sea level rise
- C. slow sedimentation during a fast eustatic sea level rise
- D. all of these. E. none of these.
- A. fast sedimentation during a slow eustatic sealevel rise D. all of these.
- C. fast sedimentation during a slow eustatic sealevel fall
- B. slow subsidence during a fast eustatic sealevel fall E. none of these.
- C. fast uplift during a slow eustatic sealevel rise
- C. slow uplift during a fast eustatic sealevel rise
The shoreline always moves seaward during a _________________________.
A. transgression B. regression C. eustatic rise in sea level D. eustatic drop in sea level E. both A. & C.
The shoreline ALWAYS moves sea/landward during a:
A. transgression B. regression C. eustatic rise in sealevel D. eustatic fall in sealevel E. both A. & C.
The shoreline PROBABLY would move seaward, but it MIGHT move landward during a:
A. transgression B. regression C. eustatic rise in sealevel D. eustatic fall in sealevel E. both B. & D.
Which diagram on the board shows the sedimentary sequence generated by a transgression followed by a regression?
A. B. C. D. E. all of these
A worldwide (not a local) change in sea level is called a _________________.
A. regression B. transgression C. relative change in sea level D. eustatic change in sea level E. none of these
What does the diagram to the left below indicate?
- A. A transgression followed by a regression.
- B. A regression followed by a transgression.
- C. A transgression followed by a regression followed by a transgression.
- D. A regression followed by a transgression followed by a regression.
- E. None of these.
Which diagram below shows the sedimentary sequence generated by a regression/transgression followed by a transgression/regression? (The diagram immediately below shows the lateral distribution of facies).
During a ________________________, the shoreline moves seaward.
The shoreline moves seaward during a ___________.
The shoreline moves land/seaward during a _________________.
The shoreline moves _____________________ during a transgression.
___________________ changes in sealevel are worldwide changes in sealevel.
Worldwide changes in sealevel are called ____________ changes in sealevel.
_____________________________ changes in sealevel are worldwide.
___________________ changes in sealevel are caused by continental glaciation & seafloor spreading rate changes.
3
A well sorted rock has grains with a wide range of sizes.
A poorly sorted rock has grains with a wide range of sizes.
Poorly-sorted sediments exhibit a small range of grain sizes.
Well-sorted sediments exhibit a small range of grain sizes.
Well-sorted sediments exhibit a wide range of grain sizes.
A rock bound by matrix is generally well sorted.
Very fine grained sediment binding larger grains in poorly to moderately sorted deposits is called MATRIX.
Sand dune sandstones deposited by wind in deserts is generally poorly sorted.
Sand dune sandstones deposited by wind in deserts is generally well sorted.
Alluvial fan deposits & glacial tills are generally well-sorted.
Small sediment grain size indicates quiet water conditions.
Small sediment grain size indicates high energy, fast velocity conditions at the site of deposition.
Large sediment grain size indicates quiet water conditions.
Lagoonal sediments are generally sand sized because lagoons are usually quiet water environments, with small current velocities.
Floodplain sediments are generally sand sized because flood waters have small current velocities after they overflow the river banks.
Braided stream deposits are dominated by mud, & contain only a small amount of sand.
The rock being passed around contains abundant angular & subangular grains.
What sediment size would you expect to find in QUIET WATER lagoons away from washover fans & tidal inlets?
A. gravel B. sand C. both A. & B. D. mud E. none of these A. cobbles B. pebbles C. sand D. A., B. & C. E. mud
_______________________________-sorted sediments exhibit a SMALL range of grain sizes.
_______________________________-sorted sediments exhibit a LARGE range of grain sizes.
________________ is the name given to very fine grained sediment binding larger grains in poorly or moderately sorted deposits.
Braided streams deposits usually consist of ___________________________-grained sediments.
Glacial till is usually ___________________________-sorted.
4
Cross bedding is often formed by ripples.
Thick beds of well-sorted cross-bedded sand result from sand dune deposition, often in DESERTS.
Graded bedding is a primary sedimentary structure.
Graded bedding is often found in deep-marine sediments.
Muddy layers on floodplains often exhibit mud cracks.
Floodplain sediments usually exhibit mud cracks.
Floodplain muds usually exhibit graded bedding.
Floodplain muds usually exhibit graded bedding.
The mud layers at the top of deep-marine turbidites usually exhibit mud cracks.
Muddy layers at the top of graded bedded turbidites usually exhibit mud cracks.
VARVES are deposited seasonally as light and dark layers in PLAYA LAKES.
Paleocurrent directions can be obtained from ___________________________.
A. mud cracks B. trace fossils C. cross-bedding D. ripple marks E. both C. & D.
Which of the following sedimentary structures would not be found on an alluvial fan?
A. mud cracks B. graded bedding C. asymmetrical ripples D. cross-bedding E. none of these
Which of the following would indicate deposition in a subaerial continental environment?
A. symmetrical ripples B. asymmetrical ripples C. graded bedding D. cross bedding E. mud cracks
_________ would not indicate deposition in a submarine or subaqueous environment.
A. cross bedding B. mud cracks C. graded bedding D. symmetrical ripples E. asymmetrical ripples
Varved sediments would be found in ________________ environments of deposition.
A. fluvial B. shallow-marine C. deep-marine D. glacial E. desert
Which of the following sedimentary structures would you NOT expect to find in DEEP-MARINE sediments?
Which of the following sedimentary structures would you expect to find in deep-marine sediments?
A. cross-bedding B. mud cracks C. graded bedding D. both A. & C. E. none of these
A. cross-bedding B. mud cracks C. graded bedding D. all of these E. none of these
Turbidites are mostly found in _______________ environments of deposition.
A. Fluvial B. shallow-marine C. deep-marine D. glacial E. desert
Sediments containing graded bedding are mostly found in _______________ environments of deposition.
A. Fluvial B. deep-marine C. shallow-marine D. glacial E. desert
Sedimentary structures indicating exposure to air & drying out, that is subaerial environments, are called __________________________________________.
___________________________ (a sedimentary structure) form only in environments where the sediment is exposed to air & dries out.
Transitional & continental subenvironments of deposition subject to drying exhibit a type of sedimentary structure known as ________________________________.
VARVES are deposited seasonally as light and dark layers in _____________________ lakes.
Turbidity currents in deep-marine subenvironments deposit sediment which exhibit a type of sedimentary structure known as ________________________________.
Turbidity currents in deep-marine subenvironments deposit sediment which exhibit a type of sedimentary structure known as ____________________________________.
5
DELTAS form where rivers deliver sediments faster than marine processes can redistribute them.
BARRIER ISLANDS occur where tidal ranges are large (>2 m).
Shallow-marine continental shelves lie at depths greater than 200 m.
CaCO3 (calcium carbonate) sediments occur both in deep-marine (for example, Mid-Ocean Ridge) & shallow-marine (for example, coral reefs) subenvironments.
CaCO3 sediments occur both in deep-marine (for example, seamounts) and shallow-marine (for example, coral reefs) subenvironments.
Carbonate sediments always indicate a shallow-marine environment of deposition.
Carbonate sediments sometimes indicate a deep-marine environment of deposition.
Sandy sediments occur both in deep-marine & shallow-marine subenvironments.
ABYSSAL PLAINS often contain sandy sediments in the form of turbidites.
Which is an example of a continental subenvironment?
A. delta B. barrier island C. estuary D. all of these E. none of these
Which of the following is a subenvironment of the CONTINENTAL environment of deposition?
A. Deltas B. Barrier Islands C. Alluvial Fans D. all of these E. none of these
A river flood plain is a subenvironment of the _______________ Environment of Deposition.
A. Shallow-Marine B. Transitional C. Continental D. Deep-Marine E. none of these C. Nonmarine
Which of the following are not subenvironments of the Transitional Environment of Deposition?
A. Alluvial Fans B. Floodplains C. Continental Slopes D. Abyssal Plains E. all of these
Which is an example of a transitional subenvironment?
A. delta B. barrier island C. estuary D. all of these E. none of these
A barrier island is a subenvironment of the ________________ Environment of Deposition.
A. Continental B. Transitional C. Shallow-Marine D. Deep-Marine E. both A. & B.
_________________ form where rivers deliver sediments faster than marine processes can redistribute them.
A. Carbonate platforms B. Deltas C. Sand dunes D. Barrier islands E. none of these
Which of the following is a subenvironment of the MARINE environment of deposition?
A. Deltas B. Barrier Islands C. Alluvial Fans D. all of these E. none of these
SABKHAS, supratidal marshes in arid regions, are associated with shallow-marine ______________________.
A. carbonate platforms B. deltas C. sand dunes D. barrier islands E. none of these
In which subenvironment are coral reefs found?
A. shallow-marine B. deep-marine C. estuary D. delta E. none of these.
The sediments found on the Mid-Ocean Ridge & on seamounts are _________________.
A. turbidites B. CaCO3 C. clay D. sand E. none of these.
What environment of deposition does the Mid-Ocean Ridge represent?
A. deep-marine B. shallow-marine C. delta D. fluvial E. glacial
Meandering rivers & braided streams make up thE ________________ subenvironment of the Continental Environment of Deposition.
The ____________________________________ subenvironment of the Nonmarine Environment of Deposition is made up of meandering rivers & braided streams.
____________________________________ make up the lacustrine environment of deposition.
Channel deposits incorporated into point bars, levees of silt & fine sand, & widespread muddy floodplains are characteristic of ______________________________ rivers.
Transitional subenvironments at the mouths of sediment-rich rivers are ________________ .
___________________________ (subenvironment of deposition) form where rivers deliver sediment faster than marine processes can redistribute it.
Transitional subenvironments where the tidal range is less than 4 m are __________________ .
____________________________ form where tidal ranges are LARGE (>2 m), while BARRIER ISLANDS form where tidal ranges are SMALL (<1m)
____________________ form wheretidal ranges are SMALL (<1m), while TIDAL FLATS form where tidal ranges are LARGE (>2 m)
______________________ form where tidal ranges are large (>2 m), while BARRIER ISLANDS form where tidal ranges are small (<1 m)
___________________________ (subenvironment of deposition) form where tidal ranges are small (<1 m).
Shallow-marine terrigenous subenvironments also are called continental _______________ .
The ___________________ environment of deposition lies deeper than 200 m.
The ___________________________ subenvironment lies deeper than 200 m.
Matching: Match sub-environments on the left with the major environment of deposition on the right. Each item on the right will be used more than once. Enter your answers on the computer answer sheet. Abyssal plains A. Marine
Wave dominated shelves B. Transitional
Beaches C. Continental
Lagoons
River channels
Alluvial fans
Coral reefs
Deltas
Alluvial fans
Glacial lakes

Matching: Match the environments of deposition on the left with the category on the right to which each environment of deposition belongs & enter your choice on the compurter answer sheet. Each item on the right may be used more than once.

35. Abyssal plains A. Marine
36. Continental shelves B. Transitional
37. Barrier islands C. Nonmarine (Continental)
38. Playa lakes
39. Meandering rivers

Matching: Match a feature on the left with the subenvironment on the right in which that feature occurs. Each item on the right will be used only once, but 1 item on the right will not be used. Enter your choice on the computer answer sheet.

playa lakes A. Marine
lagoons B. Barrier island
continental rise C. Delta
floodplains D. Desert

Matching: Match a feature on the left with the subenvironment on the right to which that feature pertains. Each item on the right may be used more than once, & not all items on the right will be used.

tidal range greater than 4 m A. Shallow-marinel
lagoons B. Deep-marine
continental shelf C. Delta
coral reefs D. Barrier island
floodplains E. Estuary
desert sand dunes F. Fluvial
continental rise G. Alluvial fan
levees H. Eolian
playa lakes

Red sediments indicate non-oxygenated & reducing conditions because carbon is preserved & iron combines with sulfur rather than with oxygen.

Black sediments indicate non-oxygenated & reducing conditions because carbon is preserved & iron combines with sulfur rather than with oxygen.

Black sediments indicate oxygenated conditions because iron combines with oxygen to form hematite.

Sedimentary rocks will be black if they contain a lot of carbon.

Sedimentary rocks will be RED if they contain a lot of hematite.

Sedimentary rocks will be BLACK if they contain a lot of carbon.

In which subenvironment might RED-colored sediments be found?

A. deep-marine clays B. alluvial fan sands C. floodplain muds D. all of these E. none of these

In which subenvironment might RED-colored sediments be found?

A. deep-marine clays B. alluvial fan sands C. desert sands D. all of these E. none of these

In which subenvironment might BLACK-colored sediments be found?

A. deep-marine clays B. lagoonal muds C. shallow-marine muds D. all of these E. none of these

Cretaceous deep-marine clays were _____________-colored.

A. green B. red C. black D. brown E. none of these

________________________-colored sediments containing abundant hematite indicate well-oxygenated conditions.

______________________-colored sediments containing abundant iron sulfide or carbon indicate poorly-oxygenated conditions.

__________________________-colored sediments sediments indicate non-oxygenated & reducing conditions because carbon is preserved & iron combines with sulfur rather than with oxygen.

_________________________-colored sediments indicate poorly-oxygenated conditions.

Sedimentary rocks will be __________________________ (a color) if they contain a lot of carbon or iron sulfides.

Sedimentary rocks will be ________________________ if they contain a lot of hematite.

Ash beds are not useful for demonstrating time equivalence in different sections.

Ash beds are useful for demonstrating time equivalence in different sections.

Biozones usually are NOT considered to be time equivalent & are not useful in establishing time-stratigraphic units.

Biozones usually are considered to be time equivalent & are not useful in establishing time-stratigraphic units.

Biozones are usually nearly time synchronous.

Biostratigraphic units are usually nearly time synchronous.

Biostratigraphic units approximate time equivalent units.

Lithostratigraphic units are not the same age everywhere they occur.

Lithostratigraphic units are the same age everywhere they occur.

Lithostratigraphic units (formations) are usually nearly time synchronous.

Formations are often time transgressive.

A formation (the fundamental lithostratigraphic unit) is always the same age everywhere it occurs.

The Tapeats Sandstone is the same age everywhere it occurs.

Magnetopolarity zones are often time transgressive.

Magnetopolarity zones are time synchronous.

A guide fossil is easily identified, is geographically widespread, & has a relatively short geologic range.

The process of demonstrating lithologic equivalency is the only type of correlation.

Which of the following would NOT be useful for establishing time equivalence for sequences at 2 outcrops?

A. identical biozones B. identical ash beds C. identical lithologies D. identical paleomagnetics E. identical guide fossils E. none of these

Which of the following characteristics must a guide fossil have?

A. easily identified B. geographically widespread C. relatively short geologic range D. all of these E. none of these

Which of the following would probably be a good guide fossil?

A. Lingula B. Latimeria C. opposum D. All of these E. None of these

A biozone is often nearly time synchronous / time transgressive (circle one). [Note: a biozone is the fundamental biostratigraphic unit & is based on a recognizable assemblage of fossils).

________________________________ zones approximate time equivalent units.

The following questions concern the diagram below.

The ash beds in the diagram are time synchronous.

Which of the following are or are nearly time synchronous?

A. Top of Biozone Z B. Veronica Schist C. Michael Limestone D. Theodore Sandstone E. Betty Ann Shale D. all of these E. none of these A. Lynn Limestone B. Stephen Shale C. Volcanic Ash A2 B. Brian Basalt C. Fossil Assemblage X

What type of unconformity is the contact between the Precambrian Veronica Schist & the Ordovician Theodore Sandstone?

What type of unconformity is the contact between the Brian Basalt and the Shannon Sandstone?

A. nonconformity B. angular unconformity C. disconformity D. both A. & C. E. none of these

Assumming that the Veronica Schist is a metamorphosed deep-marine continental slope mud, which of the following statements based on Walthers's Law is NOT true?

A. The deep-marine mud environment of deposition is immediately adjacent to the sandstone environment of deposition.
B. The sandstone environment of deposition is immediately adjacent to the shale environment of deposition.
C. The shale environment of deposition is immediately adjacent to the limestone environment of deposition.
D. both B. & C. E. none of these

The stratigraphic section in the diagram has resulted from a __________.

A. transgression followed by a regression B. transgression C. regression followed by a transgression D. regression E. transgression followed by a regression followed by a transgression

The Stephen Shale in the diagram would have been deposited in the ___________________________________ subenvironment of deposition.

The Michael Limestone in the diagram would have been deposited in the deep-marine / shallow-marine / fluvial / glacial (circle one) environment of deposition.

The Michael Limestone in the diagram would have been deposited in the ___________________________________ subenvironment of deposition.

An unconformity cut into metamorphic or igneous rocks & overlain by sedimentary rocks is called a disconformity.

An unconformity where overlying & underlying strata are parallel is called a/nonconformity/n angular unconformity.

Which diagram below shows a DISCONFORMITY/ANGULAR UNCONFORMITY/NONCONFORMITY?

A. B. C. D. all of these E. none of these

The stratigraphic relationship between the layered sedimentary strata & the igneous intrusion in the diagram below is called a(n) _____________.

A. bedding plane B. hiatus C. angular unconformity >D. disconformity E. nonconformity

An unconformity where overlying & underlying strata are parallel to each other is called a(n) _____________.

A. disconformity B. angular unconformity C. nonconformity D. bedding plane E. None of these

Which statement(s) below are true concerning how diastems & unconformities DIFFER from one another?

A. An unconformity is a surface of nondeposition or erosion; a diastem is not.
B. The beds overlying & underlying an unconformity are never parallel; the beds on either side of a diastem are always parallel.
C. An unconformity represents a significant amount of time; a diastem represents a relatively short interval of time.
D. all of these E. none of these.

Which statement(s) below are true concerning how bedding planes & unconformities DIFFER from one another?

A. An unconformity is a surface of nondeposition or erosion, while a bedding plane is not.
B. The beds overlying & underlying an unconformity are never parallel, while the beds on either side of a bedding plane are always parallel.
C. An unconformity represents a significant amount of geologic time, while a bedding plane represents short periods of time (less than a few years). D. all of these E. none of these.

An ________________________________________________ is an unconformity where overlying & underlying strata

have different dips.

A ________________________________________________ is an unconformity where overlying & underlying strata have the same dips.

Short Answers: Briefly answer the following questions.

Fill in the blanks provided to the right of the 2 diagrams below as to the combination of transgressions & regressions needed to cause the observed stratigraphic section.

_______________________________________

______________________________________

List the 3 major environments of deposition and the subenvironments of each.

What is the cause & significance of a) mudcracks, b) graded bedding & c) cross bedding?

Matching: Match items on the left with the appropriate rock types on the right. Each item on the right will be used only once.

Broad stable shallow marine shelf A. Limestone
Deep sea trench at a convergent plate boundary B. Subgraywacke
Major river delta C. Arkose
Rift valley alluvial fans D. Quartz sandstone
Deep marine Mid-Ocean Ridge E. Graywacke
Tropical marine shelf

Matching: Match rock types on the left with the appropriate description on the right. Each item on the right will be used only once.

Arkose A. Consists of calcium carbonate
Quartz sandstone B. Contains a poorly-sorted mix of quartz, feldspar, & rock fragments in a clay matrix
Graywacke C. Silica-cemented, with well-sorted, well-rounded quartz grains
Subgraywacke D. Hematite-cemented sandstone containing abundant feldspar grains
Limestone E. Characteristic of deltas

Red Rock Specimen: The following questions concern the red rock on the table at the front of the room. Please go up one at a time to examine the rock & do this section.

What is the rock name of this specimen?
A. shale B. sandstone C. limestone D. chert E. conglomerate
What is the grain size of this rock?
A. clay B. silt C. sand D. gravel E. both A. & B.
What are the primary sedimentary structures on the exposed surface of the specimen?
A. ripple marks B. mud cracks C. cross bedding D. trace fossils E. none of these
What does its red color indicate?
A. deposition in an oxidizing environment B. hematite in the rock C. deposition in a reducing environment D. pyrite in the rock E. both A. & B.
What major environment of deposition could this rock represent?
A. Continental B. Transitional C. Marine D. both A. & B. E. all of these
What sub-environment of deposition might this rock represent?
A. flood plain B. tidal/mud flat C. both A. & B. D. river channel E. barrier island

Rock Specimens: The following questions concern the rock specimens on the table at the front of the room.

What is the rock name of rock specimen #1?
A. shale B. sandstone C. limestone D. chert E. conglomerate
What is the largest grain size of rock specimen #2?
A. clay B. silt C. sand D. gravel E. both A. & B.
What are the primary sedimentary structures on the rock specimen #3?
A. ripple marks B. mud cracks C. cross bedding D. trace fossils E. none of these
What is the rock name of rock specimen #4?
A. shale B. sandstone C. limestone D. chert E. conglomerate
What is the rock name of rock specimen #5?
A. shale B. sandstone C. limestone D. chert E. conglomerate

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