Study Questions for
Sedimentology and Stratigraphy


Note that the study questions are presented here as open ended responses. This is a useful framework for testing your understanding of concepts. All exams in this course will include three sections: (1) definitions (1-2 sentences max.), (2) short answer (3-4 sentences or an annotated sketch) and (3) Essays (2-3 paragraph responses perhaps with an annotated sketch). The questions below reflect some of the more important material covered in lecture. You will do well in this course if you know the answers to these questions.  Of course, other material will also be on the exams, with about 5-10% of each exam focused on topics covered in the reading that were not discussed in class.
How to use these study questions:

 
    1. The table below lists topics by exam. The "Last Topics" column lists material presented after Exam 3.
        Note that the final exam is cumulative.

    2. After attending lecture, attempt to answer as many of the questions as possible.  Use the textbook as an
        additional resource.

    3. Note that the goal is to understand the concepts behind the study questions - writing down the answers may
        just be the first step to this understanding.

    4. If a question is particularly difficult for you, think about how other elements in the lecture might relate to that
        concept. For example, when considering how one facies model might differ from another, recall the transport  
        processes that operate in each environment, the types of sedimentary structures you might expect to find in them
        and how the composition of rocks in those environments will differ
.

    5. If you have questions with a concept, ask the instructor, or TA during office hours.

About the Final Exam:

    1. The final exam is cumulative.

    2. About 70% of the material on the final will be taken from lectures given after Exam 3 ("Seismic Stratigraphy" through
        "Future of Sedimentology").  Please use the most recent set of review questions below as an aid in preparing
for this part
        of the exam.

    3. About 30% of the material on the final focuses on the "big picture concepts" listed on the Final Exam Study Sheet
        These
concepts were all introduced during earlier parts of the course ("Introduction" through "Radiometric Dating") and
        were covered by the midterms.

      You've learned a lot about the Stratigraphy! 

      Good luck with your studying!


To view the study questions by topic, click on the link below


Exam 1
Exam 2
Exam 3
Last Topics
Intro to Sedimentary Geology Wather's law and the facies concept Stratigraphic Principles
and Units

Seismic
Stratigraphy

Weathering rates and processes  Fluvial and Lacustrine Environments

Lithostratigraphy:

The nature of the stratigraphic record

Plate Tectonics and Sedimentation
Siliclastic rocks
Eolian and Deltaic environments

Stable Isotopes, Ice Volume and Oxygen Isotope Stratigraphy

Basin Analysis
Fluid flow and sediment transport
Clastic Tidal and
Beach Environments

Classical
Biostratigraphy
Sea Level Change
and Sedimentation

Grain size analysis
Marginal
Marine Environments

Quantitative
Biostratigraphy
Sequence Stratigraphy - Theory
Particle shape and sediment fabric
Pelagic Environments
Core and Wireline
Logging
Sequence Stratigraphy - Application
Sedimentary structures
Carbonate
Sedimentary Rocks

Magneto- and
Chemostratigraphy
Sedimentary
Resources

  Shallow Water
Carbonate Environments

Radiometric
Dating

Applied Sedimentology
(Future of Sedimentary Resources)

  Evaporitic
Environments


 

Intro to Sedimentary Geology

What are the principle fields of Sedimentary Geology? How do these subfields differ?
        What questions are of interest to softrock geologists?
        What do these fields teach us about the world around us?
        What scales of processes are important in Sedimentary Geology?
        What are some examples of processes important in Sedimentary Geology? 
    

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Weathering rates and processes 

        What are the principle mechanisms of weathering?
        How might these processes have changed through time?
        How does weathering influence crustal composition?
        What factors influence rates of weathering?
        What role does weathering play in the rock cycle?
        What are some of the products of weathering processes
?

        back to topics

Fluid flow and sediment transport

        How does shear stress influence fluid flow and sediment transport?
        What is shear velocity? How does it relate to shear stress?
        What physical properties determine how a fluid responds to flow and stress?
        How do various classes of fluids respond to shear stress? 
        What is the no slip condition? 
        What is the difference between laminar and turbulent flow?  Between tranquil and rapid flow?
        Explain the meaning of the various terms in the Reynolds, Froude, and Rouse number
        Why do sedimentologists care about these numbers?      
        What type of particle motion is described by the impact law? By Stokes law?  How are they related?
        Describe the ways that particles can be transported by (1) fluids, (2) dry mass wasting, (3) wet mass wasting.
        What is normal grading? In which type(s) of flow processes is it seen?
        What is reverse grading? In which type(s) of flow processes is it seen?

back to topics

Grain size analysis

        Describe three different scales with which sediment grainsize can be compared?
        What are the pros and cons of the various ways of presenting grain size data?
        Discuss the three measures of central tendency discussed in class?
        What is skewness?  
        What can the relationship between the various measures of central tendency tell us about skewness?
        Describe how to calculate grainsize statistics using the graphical method and the method of moments.

back to topics

Particle shape and sediment fabric

        Discuss the relationships between form (shape) roundness (angularity), and surface texture?
        What can we learn about sedimentary rocks from these concepts?
        What determines the degree of sorting in a sedimentary rock?
        What factors control sediment fabric?
        What can we learn from sediment fabric?
        What is imbrication?

          back to topics

Sedimentary structures

        What processes can form sedimentary structures? What can we learn from them?
        What are the principle classes of sedimentary structures? How does each form?
        How can sedimentologist infer paleocurrent direction?
        What controls the size of bedforms in sedimentary environments?
        Do bedforms form any clear progressions? If so, what?
        What factors influence ripple morphology?

 back to topics

Siliclastic rocks

        Sedimentary rocks consist of what three general classes of material?
        Discuss the components of Gilbert's classification scheme as presented in Figure 5.5 from Boggs?
        How does it differ from that of Folk or Robinson as presented in Figure 5.4 from Boggs?
        What terms are used to describe sedimentary rocks on the basis of their formation process,
        or the location in which they formed?
        What are the three stages of diagenesis discussed in class?  What processes are associated with each of them?

         back to topics

Walther's law and the facies concept

        What are the basic stratigraphic principles or laws?
        What are facies and what is Walther's law?
        Why might some sedimentologists consider Walther's law the most important stratigraphic principle?
        What processes control the vertical succession of facies?

         back to topics

Fluvial and Lacustrine environments 

        Which terrestrial environments can generally be observed in the sedimentary record?
        Describe the sedimentary structures present in these environments?
        How does the position of these environments relate to their distance above base level?
        Describe or sketch facies models associated with these environments?

         back to topics

Eolian and Deltaic environments

 
       Describe the types of sedimentologic features you would expect to see in an eolian deposit?
        What are some of the subenvironments found in a delta?
        Discuss the classification of deltas by Galloway. What processes define the geomorphology of deltas?
        What is progradation? How does it influence the age relationships between facies within a delta?
        Describe the properties of an idealized deltaic facies model.        

        back to topics

Clastic Tidal and Beach Environments

 
       What are the types of tidal forcing patterns?  Why do they differ?
        What sedimentary structures and fabrics are common in tidal environments?
        Describe the components of a simple tidal facies model?
        How are beach environments classified? How does this relate to the deltaic classification scheme we studied?
        What subenvironments are found in barrier island and beach environments?
        Why are these environments economically important?
        What types of barrier island facies models would be generated in response to transgression, regression?
        What is the relationship between bedding planes and time lines in the inlet facies model?

        back to topics

Marginal Marine Environments

 
 
     What processes can transport sediment from continental shelf environments to the abyssal plains?
        How does the relative importance of storms versus tides influence the types of bedforms and sedimentary
        structures found in sediments of the marginal marine environments?
        How do linear sand ridges differ from tidal ribbons, tidal sand ridges, and tidal sand waves?
        How do these features form?
        Describe facies models for the the shelf, slope, and rise?
        Why are deposits from these regions economically important?          

        back to topics

Pelagic Environments

        What are the most abundant sedimentary environments on the planet?
        How are modern sediments extracted from the deep sea?
        What are turbidites? Why do they matter? How can they be identified?
        What types of structures and features can be found in the deep sea?
        What are the principle sediment types found in the deep sea?
        What controls the distribution of sediments in the deep sea?
       
 
        back to topics

Carbonate Sedimentary Rocks

        Describe the controls on shallow water carbonate precipitation.
        What role does biology have in carbonate deposition - describe the classes of mediated
        precipitation discussed in class?
        Discuss the various carbonate classification schemes describe in class. What are their relative
        strengths and weaknesses?
        What types of allochems and orthochems combine to produce carbonate rocks?
        How can orthochems tells us about the history of a carbonate rock?
        In what ways can lime mud form?
        What factors influence the stability of carbonate minerals?
        In what ways can carbonate rocks be influenced by diagenesis and alteration?

        back to topics

Shallow Water Carbonate environments
      
        What are the principle types of tidal carbonate environments?
        How does the biogenic carbonate produced in various subenvironments differ?
        What types of barriers can protect tidal carbonate flats?
        Discuss the differences between subtidal and tidal carbonate facies.
        What is a shallowing upward sequence?
        How do carbonate environments respond to eustacy?
        Contrast ancient carbonate sequences with modern analogs?
        Describe the growth patterns of carbonate platforms and reef complexes.
        How does carbonate rock classification relate to paleoenvironmental interpretation?
        What hypotheses have been proposed for lime mud production in shallow water carbonate systems?
        What hypotheses have been proposed for cyclicity in shallow water carbonate systems?
        Describe facies models for carbonate systems responding to different types of forcing.

        back to topics

Evaporitic Environments

 
      What evaporitic minerals are common in marine and non-marine evaporitic environments.
       What two evaporitic minerals differ only by their water of hydration?
       How does this influence evaporitic strata?
       What is "chicken wire" fabric? How does it form?
       How might thinly laminated evaporites form?
       Describe the modern environments in which evaporites form?
       Do evaporites form in the same way in all of these environments (See the textbook for details here)?
       What types of sedimentary structures are associated with evaporitic environments? 
       Discuss the models for evaporite production that have been proposed? Are they all equally plausible?

        back to topics

Stratigraphic Principles and Units
      
        Describe the nature of contacts in the stratigraphic record? What can we learn from them?
        What types of grain size trends are associated with transgression and regression?
        What are the factors that influence the symmetry of sea level cycles?
        What is the nature of the stratigraphic record according to Derek Ager?
        Define the terms that stratigraphers use to discuss strata and their temporal relationships.
        How do time units, time-rock units, and rock units relate?
        Discuss the differences between the various types of unconformities.
        Sketch out the development of a lacuna in a passive marine setting in response to a major eustatic cycle.

        back to topics

Lithostratigraphy: The Nature of the Stratigraphic Record
      
        Discuss the nature of the stratigraphic record with respect to completeness and time.
        What is “catastrophic uniformitarianism”?
        What are some biases that may influence Derek Ager's views on the stratigraphic record?
        What are some of the methods that can be used to correlate sections?
        What are some factors that can bias or make correlation of sections difficult?
        How does lithostratigraphy relate to chronostratigraphy?
        Describe some environments in which diacronous facies may be laid down?
        Describe the development of the sequence stratigraphic concept.
        What processes drive the development of sequence boundaries and the deposition of strata in sequences?
        What are the advantages and weaknesses of the sequence stratigraphic approach?
        Discuss how nested cyclicity relates to the sequence stratigraphic approach?

       back to topics

Stable Isotopes, Ice Volume, and Oxygen Isotope Stratigraphy
      
        How are oxygen isotopes applied to address stratigraphic questions?
        What pre-depositional, depositional, and post-depositional processes contribute to the oxygen isotope record?
        Describe the methods used to measure oxygen isotopes.
        What phases are analyzed to generate oxygen isotopic data?
        What are the advantages and disadvantages of various phases used to measure oxygen isotope data?

       back to topics

Classical Biostratigraphy

        How can climate events leave a biostratigraphic imprint?
 
       What are the dangers of placing stratigraphic boundaries at "natural breaks" in the biostratigraphic record?
        How does a biologist's definition of a species differ from a paleontologist's taxon?
        What factors make a fossil biostratigraphically useful?
        What factors can limit the usefulness of fossils as time markers?
        Do fossils provide estimates of absolute or relative time?
        Describe the various types of zonation schemes in use. How do they differ?
        What are their strengths and weaknesses?

        back to topics

Quantitative Biostratigraphy

        Discuss some of the potential problems with classical biostratigraphy.
        Do FAD's and LAD's represent minimum or maximum estimates of the true depth of occurrence?
        What alternatives for estimation of age using biostratigraphic data have been proposed?
        Describe how Shaw's method is used?
        What can be learned using Shaw's method?
        Why does Shaw's method work?

        back to topics

Core and Wireline Logging

        How can various aspects of the electromagnetic spectrum be used to generate stratigraphic data?
        What is the difference between active and passive tools using gamma rays?
        What information can be derived from resistivity data?  What are some of the tools that use resistivity data for
        for core logging?
        What is LWD, or MWD?  How does it differ from standard wireline logging?
        Is the measurement geometry for natural gamma measurements on cores favorable relative to downcore
        natural gamma measurements?
        How can sound be used to obtain stratigraphic data?
        Logging data is most powerful when used in what way?

        back to topics

 Magneto- and Chemostratigraphy

         What does the Earth's magnetic field have to do with stratigraphy?
         What types of paleomagnetic information can be used stratigraphically?
         What is the advantage of radiometrically calibrated magnetostratigraphy?
         What factors influence the quality of the paleomagnetic record?
         How can magnetic signatures be recorded in hard rock and in sediments?      
        What is chemostratigraphy?
        Why can the oxygen isotopic composition of the ocean be used stratigraphy?
        What are the conventions for the naming of oxygen isotope stages and substages?
        Are these formal stratigraphic units as defined in the North American Stratigraphic code?
        How can paleomagnetics, oxygen isotopes, and radiometric dating be used in concert?

        back to topics

 Radiometric Dating

        What is an element, atom, isotope?
        What is radiometric decay? How does it differ from a linear decay law?
        What is a half-life, and what are parent and daughter products?
 
       What is a decay series?
        Derive the half-life from the basic radiometric decay equation.
        Discuss the meaning of accuracy, precision, and resolution
        What types of instruments are used to measure radioisotopes?
        Which isotopic systems are best matched to different dating problems?

        back to topics

Seismic Stratigraphy

        What physical factors influence the speed of sound in sediments and rocks?
        Describe the basis principles by which seismic methods work?
        Sketch out typical patterns generated by seismic reflectors (e.g onlap vs. downlap, etc).
        What can be learned from analysis of seismic sections?
        Define Seismic Stratigraphy. How does it relate to Sequence Stratigraphy?

 
       back to topics

Plate Tectonics and Sedimentation

        Define the terminology used to describe basins prior to the development of the theory of Plate Tectonics.
        What were the limitations and difficulties associated with this terminology as applied by American and European
        Stratigraphers?
        Describe the types of basins associated with the three types of plate boundaries.
        Discuss the evolution of a passive margin basins?
        What is an alucogen? How do they form?

        back to topics

Basin Analysis

        Describe what sedimentary geologists can learn from isopach, structure contour, and facies maps, fence diagrams.
        What is basin analysis? Why is it useful?
        What is geohistory analysis?  What are the underlying data and assumptions behind the method?

        back to topics

Sea Level Change and Sedimentation

        What is relative sea level? How does it differ from mean sea level?
        What is accommodation space?
        What factors influence relative sea level change? Which are dominant?
        How do these factors influence accommodation space?
        How do transgression, regression, and still stand relate to the facies deposition on continental margins?
        How do differences in the factors influencing accommodation space alter the geometries of continental margins?
        Describe the development of the Vail Sea level curve.

        back to topics

Sequence Stratigraphy - Theory

        Define the components of a "sequence" as defined by sequence stratigraphers.
        How do the sequence boundaries differ from lithostratigraphic horizons?
        Define the difference between a Type 1 and Type 2 sequence boundary.
        What stratigraphic features (and relative sea level phases) are each of these boundaries associated with?
        How do Type 1 and Type 2 boundaries form in response to the dominant factors influencing relative sea level?

        back to topics

Sequence Stratigraphy - Application

        We discussed three applications of sequence stratigraphy in detail in class. These were the "Jurassic Tank" experiments of
        Paola et al, Holland's revision of the Ordovician Cincinnati Arch Stratigraphy, and the Tornqvist paper on the nature of
        sequence boundaries. Here are some study questions related to those papers.

        As discussed in the Paola article, what three approaches are used to help understand and interpret the ancient stratigraphic      
        record? What hypotheses was the Jurassic Tank designed to address? What are some disadvantages of physical or scale models?

        According to Holland, which sedimentary environments have been well studied from a sequence stratigraphic perspective?            
        Which have not?

        Discuss how Holland's reinterpretation of the Cincinnatian Series differs from the traditional interpretation. What problems
        does this new perspective solve. What facies does Holland recognize? How are they associated and what controls the way in
        which these sequences formed?

        According to Tornqvist, what factors influence the nature of sequence boundaries?
        At what stage of the relative sea level (RLS) curve did they argue the boundaries they observed formed?
        How generalizable do you think their study of fourth to fifth order sequence boundaries is to sequence boundary formation in
        general?


 
       back to topics

Sedimentary Resources

        What are the principle classes of organic rich sediments or sedimentary derived resources that we discussed in class?
        In which environments would you expect to find these resources forming?
        What are the connections between ocean circulation, bottom water oxygen content and sediment organic carbon content?

        back to topics

Applied Sedimentology (Future of Sedimentary Resources)

        Discuss some of the ways in which sedimentary resources are used by our society?
        What role do geologists (specifically stratigraphers and sedimentologists play in connection with these resources?
        What is the connection between facies, sedimentary environment and specific resources?
        What trends might you expect in terms of the future of sedimentary resources?


 
       back to topics


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