Aapg Quiz: Sequence Stratigraphy, Part 1 (Of 5)

1. A depositional sequence is

One that never uses water saturation in marker beds as sequence boundaries.

The term used to indicate that hydrothermal alteration has occurred at certain intervals in time.

A stratigraphic unit composed of a relatively conformable succession of genetically related strata and bounded at its top and base by unconformites or their correlative conformity.

Never used in deep marine clastics such as turbidites.

The analytical steps of sequence stratigraphic first identify the genetic units and boundaries that compose the stratigraphic section in outcrop, core, well-log and seismic data. The framework formed by the genetic units and boundaries is tied depositional models that explain the recurring character of the sequence stratigraphic units and surfaces and provides a common terminology for each of these models, whatever the tectonic setting, depositional setting, sediment types (siliciclastics, carbonates, evaporites) data set that is available for analysis (e.g., seismic data versus well logs or outcrop). It is generally assumed that many of the strata and surfaces are related to changes in the position of relative sea-level driven by eustasy.
http://www.sepmstrata.org/Terminology.aspx?id=sequence%20stratigraphy#

Explanation

The analytical steps of sequence stratigraphic first identify the genetic units and boundaries that compose the stratigraphic section in outcrop, core, well-log and seismic data. The framework formed by the genetic units and boundaries is tied depositional models that explain the recurring character of the sequence stratigraphic units and surfaces and provides a common terminology for each of these models, whatever the tectonic setting, depositional setting, sediment types (siliciclastics, carbonates, evaporites) data set that is available for analysis (e.g., seismic data versus well logs or outcrop). It is generally assumed that many of the strata and surfaces are related to changes in the position of relative sea-level driven by eustasy.
http://www.sepmstrata.org/Terminology.aspx?id=sequence%20stratigraphy#

2. The sequence stratigraphy method of stratigraphic interpretation

Supports the idea that convection currents and subduction zones are the key to understanding depositional models.

Combines the stratal architecture (geometric relationship) of the sedimentary facies and the chronological order of their accumulation to enhance the interpretation of depositional setting and prediction of stratal continuity.

Involves microseismic, and nothing more.

Allows the geologist to rule out salt tectonics.

The major problem with sequence stratigraphy is that the definition, terminology and interpretation of the surfaces of sequence stratigraphy is complex and sometimes contentious. In an attempt to circumnavigate this, the site places a heavy dependence on the explanation of terminology linked pop-up boxes so as to clarify the understanding and use of this discipline of stratigraphy.

Explanation

The major problem with sequence stratigraphy is that the definition, terminology and interpretation of the surfaces of sequence stratigraphy is complex and sometimes contentious. In an attempt to circumnavigate this, the site places a heavy dependence on the explanation of terminology linked pop-up boxes so as to clarify the understanding and use of this discipline of stratigraphy.

3. Walther's Law

Involves paleobotany and involves the depth and temperatures of sea water.

Establishes the geochemical signature of different formations.

Proposes that the vertical progression of facies should be the same as corresponding lateral facies changes.

Differentiates between clay minerals and carbonates.

Imagery used with SEPM permission: http://www.sepmstrata.org/Terminology.aspx?id=boundaries#

Explanation

Imagery used with SEPM permission: http://www.sepmstrata.org/Terminology.aspx?id=boundaries#

4. Sequence stratigraphy focuses on

Paleoecological frameworks characterized by unique fossil assemblage

The order in which the strata accumulated combined with depositional and erosional surface frameworks to interpret depositional settings

Basin modeling and sea level

Astroblemes and other allochthonous events that can have local and regional implications, resulting in unique traps

Sequence stratigraphy, a branch of sedimentary stratigraphy, uses the order strata accumulated in along with a framework of major depositional and erosional surfaces to interpret the depositional setting of clastic and carbonate sediments from continental, marginal marine, basin margins and down-slope settings of basins.

Explanation

Sequence stratigraphy, a branch of sedimentary stratigraphy, uses the order strata accumulated in along with a framework of major depositional and erosional surfaces to interpret the depositional setting of clastic and carbonate sediments from continental, marginal marine, basin margins and down-slope settings of basins.

5. Lithostratigraphic analysis

Maps lithofacies independent of subdividing external and internal boundaries.

Forces one to include Young's modulus values.

Always puts into question all geomechanical calculations, including pore pressure.

Establishes hiearchies of relevance, exclusing igneous intrusions.

Lithostratigraphic analysis which maps lithofacies independent of subdividing external and internal boundaries. Allostratigraphic analysis that identifies and includes as time markers bounding discontinuities including erosion surfaces, marine flooding surfaces, and markers that include tuffs, tempestites, and/or turbidite boundaries etc., but considers these as independent of any model of base level change.

Explanation

Lithostratigraphic analysis which maps lithofacies independent of subdividing external and internal boundaries. Allostratigraphic analysis that identifies and includes as time markers bounding discontinuities including erosion surfaces, marine flooding surfaces, and markers that include tuffs, tempestites, and/or turbidite boundaries etc., but considers these as independent of any model of base level change.

6. Bounding surfaces

Are subdividing surfaces of the sedimentary section and are commonly generated by the changing relative sea level.

Surfaces that never tie to rebounds due to isostacy and eustacy.

Are boundaries that never have to do shales and TOC, and cannot be considered key indicators of the kitchen.

Are blurring surfaces that have to do with fracture patterns.

Imagery used with SEPM permission: http://www.sepmstrata.org/page.aspx?&pageid=15&3

Explanation

Imagery used with SEPM permission: http://www.sepmstrata.org/page.aspx?&pageid=15&3

7. Stacking patterns include

Parasequence

Progradation

Retrogradation

Transgression

All of the above

To establish the depositional setting of the sedimentary section, sequence stratigraphy uses the geometric arrangement of sedimentary fill, particularly the vertical succession of sedimentary facies geometries and their enveloping surfaces known as stacking patterns. Imagery used with SEPM permission: http://www.sepmstrata.org/CMS_Images/wagoner-fig10Small.jpg

Explanation

To establish the depositional setting of the sedimentary section, sequence stratigraphy uses the geometric arrangement of sedimentary fill, particularly the vertical succession of sedimentary facies geometries and their enveloping surfaces known as stacking patterns. Imagery used with SEPM permission: http://www.sepmstrata.org/CMS_Images/wagoner-fig10Small.jpg

8. Stratigraphy is the science of

Time and movement.

The past is key to the present.

The present is key to the past.

Layered character of rocks.

Stratigraphy is the science of the layered character of rocks. The rocks can be sedimentary, volcanic, metamorphic or igneous. Imagery used with SEPM permission: http://www.sepmstrata.org/Terminology.aspx?id=stratigraphy

Explanation

Stratigraphy is the science of the layered character of rocks. The rocks can be sedimentary, volcanic, metamorphic or igneous. Imagery used with SEPM permission: http://www.sepmstrata.org/Terminology.aspx?id=stratigraphy

9. Sequence stratigraphy involves a geologic model that makes the following assumptions:

Sea level position varied

Subsidence was constant

Sediment supply was constant

All of the above

Imagery used with SEPM permission: http://www.sepmstrata.org/page.aspx?&pageid=15&3

Explanation

Imagery used with SEPM permission: http://www.sepmstrata.org/page.aspx?&pageid=15&3

10. Sequence stratigraphy involves combining the following:

All of the below.

Stratal architecture and the chronological order of the indicated facies along with grain size information and lithology.

The provenance of the different grains, combined with structural systems.

Diagenetic alteration and lamina.

Sequence stratigraphy involves combining stratal architecture, the chronological order of the indicated facies, grain size information, lithology, provenance of different grains, and structural systems. It also includes consideration of diagenetic alteration and lamina.

Explanation

Sequence stratigraphy involves combining stratal architecture, the chronological order of the indicated facies, grain size information, lithology, provenance of different grains, and structural systems. It also includes consideration of diagenetic alteration and lamina.