Third-order sequences and parasequence stacking patterns of Lower Ordovician platform carbonates of the El Paso Group, Franklin Mountains, west Texas
- Exxon Production Research Co., Houston, TX (United States)
The Lower Ordovician passive margin succession of the Franklin Mountains is represented by the second-order Sauk C supersequence set consisting of the Bliss Sandstone and the overlying El Paso Group. The Bliss marks the second order basal lowstand-transgressive phase and the El Paso Group records the second-order highstand. The El Paso Group contains several third-order depositional sequences, which in this updip, shelfal position lack internal stratal geometries along dip. Thus, sequences and systems tracts are identified solely on the basis of the vertical stacking patterns of depositional subfacies and high frequency, fifth-order parasequences. 'Fischer plots' of high-frequency parasequences gauge systematic shifts in third-order accommodation of two complete third-order sequences within the Arenigian portion of the El Paso Group. This is expressed in the vertical succession of parasequence types, systematic changes in parasequence thicknesses, plus variations in subfacies as revealed by histograms of subfacies types tied to 'Fischer plots.' A complete El Paso shelfal sequence contains a thin lowstand (LST) of quartzarenite, a thick transgressive systems tract (TST) dominated by upward-thickening, thrombolitic subtidal parasequences, and a highstand systems tract (HST) marked by dolomitic, thinning-upward peritidal parasequences containing admixed quartz sand. The authors have investigated the mechanics of third-order sequence formation and contrasted allocyclic models with autocyclic models for high-frequency parasequence formation through 1-D and 2-D forward modeling.
- OSTI ID:
- 5677381
- Report Number(s):
- CONF-910403--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 75:3; ISSN AABUD; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
Similar Records
Forward modeling of high-frequency, glacio-eustatic, depositional sequences: An example from Middle Pennsylvanian shelf carbonates of the SW Paradox basin, Honaker Trail, Utah
Similarities between third and fourth-order stratigraphic sequences: An example from the Permian Upper San Andres: Last Chance Canyon, Guadalupe Mountains, New Mexico
Related Subjects
580000* -- Geosciences
CARBONATE ROCKS
DEPOSITION
DEVELOPED COUNTRIES
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOLOGY
LITHOLOGY
NORTH AMERICA
ORDOVICIAN PERIOD
PALEOZOIC ERA
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
STRATIGRAPHY
TEXAS
USA