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Line 64: − [[file:exploring-for-stratigraphic-traps_fig21-16.png|thumb|{{figure number|21-16}}. Copyright: Dolson and Piombino, 1994; courtesy Rocky Mountain Assoc. of Geologists.]]+ −
Procedure for geometrical analysis (view source)
Revision as of 18:07, 23 January 2014
, 18:07, 23 January 2014no edit summary
* Evidence of widespread channeling of platforms or shelves
* Evidence of widespread channeling of platforms or shelves
* Abrupt vertical geochemical changes such as stable isotopes
* Abrupt vertical geochemical changes such as stable isotopes
[[file:exploring-for-stratigraphic-traps_fig21-16.png|thumb|{{figure number|1}}. Copyright: Dolson and Piombino, 1994; courtesy Rocky Mountain Assoc. of Geologists.]]
===Individual well evidence===
===Individual well evidence===
==Example of unconformity analysis==
==Example of unconformity analysis==
Cores and samples should be examined for evidence of unconformities. These unconformity surfaces should then be calibrated to logs. Logs can then be used to correlate the surfaces to seismic and to other wells. [[:file:exploring-for-stratigraphic-traps_fig21-16.png|Figure 1]]<ref name=ch21r12>DolsonMuller, D., S., 1994, Stratigraphic evolution of the Lower Cretaceous Dakota Group, Western Interior, U., S., A., in Caputo, M., V., Peterson, J., A., Franczyk, K., J., eds., Mesozoic Systems of the Rocky Mountain Region, U., S., A.: SEPM Rocky Mountain Section, p. 441–456.</ref> shows an example of calibrating unconformity evidence from cores to logs. The Lower Cretaceous Cutbank Sandstone unconformably overlies the Jurassic Swift Formation. A major lowstand surface of erosion (LSE) is shown at [[depth::2957 ft]] (901 m) and was identified using the following criteria:
Cores and samples should be examined for evidence of unconformities. These unconformity surfaces should then be calibrated to logs. Logs can then be used to correlate the surfaces to seismic and to other wells. The figure<ref name=ch21r12>DolsonMuller, D., S., 1994, Stratigraphic evolution of the Lower Cretaceous Dakota Group, Western Interior, U., S., A., in Caputo, M., V., Peterson, J., A., Franczyk, K., J., eds., Mesozoic Systems of the Rocky Mountain Region, U., S., A.: SEPM Rocky Mountain Section, p. 441–456.</ref> shows an example of calibrating unconformity evidence from cores to logs. The Lower Cretaceous Cutbank Sandstone unconformably overlies the Jurassic Swift Formation. A major lowstand surface of erosion (LSE) is shown at [[depth::2957 ft]] (901 m) and was identified using the following criteria:
* Missing [[biostratigraphy|biostratigraphic]] horizons
* Missing [[biostratigraphy|biostratigraphic]] horizons