Difference between revisions of "Balanced cross sections"

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==See also==
 
==See also==
* [[Prospect delineation techniques and tools]]
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* [[Seismic data]]
 
* [[Seismic data]]
 
* [[Tectonic modeling]]
 
* [[Tectonic modeling]]

Revision as of 23:05, 17 November 2014

Exploring for Oil and Gas Traps
Series Treatise in Petroleum Geology
Part Predicting the occurrence of oil and gas traps
Chapter Exploring for structural traps
Author R.A. Nelson, T.L. Patton, S. Serra
Link Web page
Store AAPG Store

Definition

Balanced cross sections honor all available data and are constructed and analyzed to ensure they are geometrically possible and geologically admissible, given reasonable assumptions about the predeformation setting of rocks and how rocks behave during deformation in a particular tectonic environment. “Balanced” refers to the basic assumption made in constructing these sections—that rock area (rock volume) does not change substantially as a result of deformation. Balanced cross sections are restorable. This means that, while maintaining constant area, the deformation displayed in a balanced cross section can be incrementally removed to yield a geologically plausible predeformation configuration.

The constant area (constant volume) assumption is generally valid for deformation that has occurred in upper crustal, nonmetamorphic settings, but there are important exceptions. For example, in some settings syntectonic deposition and compaction can result in substantial rock volume changes throughout the course of deformation. In these cases, approximations of the volume changes must be incorporated in the balancing process.

Balancing is an interative, trial-and-error process. If done manually, it is tedious and very time consuming. Computer programs greatly simplify the measurement and drafting aspects of cross section balancing. Some of these programs also incorporate functions and algorithms that permit some rudimentary 3-D balancing of structures.

Value of balancing

Balanced cross sections are not necessarily correct. However, the methodical scrutiny imposed by the balancing process highlights discrepancies in interpretations, points to the types of data or alternative schemes needed to resolve the discrepancies, and generally results in more carefully constructed, defensible, and explainable cross sections.

Further reading

Examples of use

See also

External links

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Balanced cross sections
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