Geoscience Reference
In-Depth Information
the theory of sequence stratigraphy and examples of its
application see suggested further reading in Section 6.6. Listed
below is the typical data set and general methodology for a
sequence stratigraphic interpretation.
1. Record the vertical and lateral changes in the sedimentary
succession along a proximal to distal profi le of the
depocentre. This is usually done through the graphic logs
of exposures and/or seismic sections and borehole
information. The sedimentological and palaeontological
data all need to be integrated.
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2. Incorporate any other published information (e.g.
evidence for subaerial exposure, biostratigraphy, fossil
assemblages).
3. Interpret the facies in terms of facies models so that it is
obvious where facies that are juxtaposed obey Walther's
Law and where they do not.
4. Construct, or integrate into the data set from the literature,
a robust 100 thousand year to million year resolution
relative timescale for each of the sections to enable
correlation.
5. Identify patterns and repetitions within the succession
with a view to interpreting the parasequences, their
stacking patterns and the systems tracts. The transgressive
systems tract is unique in containing retrogradational
parasequences so this is sometimes the easiest systems
tract to identify.
6. Identify major unconformity surfaces (one or more
sequence boundaries) and trace them laterally in a distal
direction to fi nd the correlative conformity. Identify
condensed sections that might represent the maximum
fl ooding surfaces and the transgressive surfaces.
7. Integrate the data on the sediment packages and key
surfaces in order to construct a sequence stratigraphic
interpretation identifying all of the systems tracts and key
surfaces.
Examples of sequence stratigraphic interpretations are beyond
the scope of this topic but Worked Example 6.3 (pp. 136-137)
illustrates data collection along a sequence boundary and
Worked Example 6.1 (pp. 124-126) also shows some sequence
stratigraphic interpretation. More extensive examples in a range
of depositional settings can be found in Coe (2003), Emery and
Myers (1996) and Catuneanu (2006).
