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Transgressive origin of channeled estuarine deposits in the Point Lookout Sandstone, northwestern New Mexico: A model for Upper Cretaceous, cyclic regressive parasequences of the US Western Interior

Journal Article · · AAPG Bulletin (American Association of Petroleum Geologists); (United States)
OSTI ID:6130976
 [1]
  1. R.P.I. International, Inc., Boulder, CO (United States)

Regionally correlatable regressions, recorded in Upper Cretaceous strata from the US Western Interior, represent low-order cyclic progradations of the epeiric seaway shoreline. Stratigraphic intertonguing of coastal sandstone deposits and marine shales developed in response to higher order depositional cycles where episodic transgressions interrupt regressions. A simple model based on Walther's Law of Facies has most often been used to interpret these deposits, including channeled estuarine sandstones commonly found at the top of the sequence. The author proposes an alternative explanation for these deposits based on time-stratigraphic architecture and component facies distributions of the Point Lookout Sandstone in the northwestern San Juan basin, New Mexico. Interpretations of outcrop measured sections and well-log correlations suggest an individual parasequence is actually the product of a depositional couplet that includes a regressive phase and a transgressive phase. Strand-plain progradation during the regressive phase produced upward-coarsening, shoreline deposits. Deposition during the transgressive phase occurred mainly in a zone landward of a reworked shoreline trend and comprises a lagoonal-estuarine system. Transgressive estuarine deposits appear to be an important potential reservoir facies in the Point Lookout section. Each estuarine sandstone is developed as a discrete reservoir unit at the landward limit of a parasequence. These sandstones can be correlated into the subsurface and their distribution mapped parallel to depositional strike. The distribution of channeled estuarine reservoirs can be predicted and effectively exploited based on the depositional couplet mode.

OSTI ID:
6130976
Journal Information:
AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 75:6; ISSN AABUD; ISSN 0149-1423
Country of Publication:
United States
Language:
English