Road Log, Day Three: Nonmarine Sequence Stratigraphy and Facies Architecture of the Updip Desert and Castlegate Sandstones in the Book Cliffs of Western Colorado and Eastern Utah
John C. Van Wagoner, 1991. "Road Log, Day Three: Nonmarine Sequence Stratigraphy and Facies Architecture of the Updip Desert and Castlegate Sandstones in the Book Cliffs of Western Colorado and Eastern Utah", Sequence Stratigraphy Applications to Shelf Sandstone Reservoirs: Outcrop to Subsurface Examples, J. C. Van Wagoner, C. R. Jones, D. R. Taylor, D. Nummedal, D. C. Jennette, G. W. Riley
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OBJECTIVES: The Desert and updip Castlegate provide an opportunity to study well-exposed sequences and systems tracts in nonmarine to marine settings. Because of the excellent quality of the outcrops, sequence boundaries can be traced continuously from the nonmarine, where the identification of sequence boundaries has historically been less certain, to the marine, where sequence boundaries can be well defined based on basinward shifts in facies. These outcrops also allow regional correlation of systems tracts and identification of exploration-scale facies changes within systems tracts. These stops demonstrate that sequence boundaries are regionally extensive, single physical surfaces that can be used to correlate in outcrop and the subsurface. These stops also show that strata between sequence boundaries are arranged in predictable packages and that facies within these packages commonly, but not always, have predictable characteristics.
0.0 Leave the parking lot of the Best Western River Terrace Motel in Green River, Utah. Turn right on the main road, Highway 6.
0.2 Turn left on the paved road. Drive north toward the Book Cliffs. This road parallels the Green River and is built on the Mancos Shale.
5.3 After ascending a hill which climbs on top of the Mancos out of the Green River alluvial valley, turn off of the paved road onto a gravel road that heads northeast directly toward Tuscher Canyon.
6.0 STOP ONE. Pull over to the side of the gravel road for an overview of the stratigraphy of the Desert Member of the Blackhawk Formation and the Castlegate Sandstone. This
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The Lower Sego provides an opportunity to study well-exposed, high-frequency sequences and their systems tracts. Criteria for identification of sequence boundaries will presented. Sequences and their boundaries will be contrasted with parasequences and their bounding surfaces. The Upper and Lower Sego contain well-exposed tidal deposits within the lowstand systems tracts of high-frequency sequences. These tidal deposits and their relationship to incised valleys and systems tracts will be examined. The incised valley interpreted to form during relative falls in sea level will be contrasted with distributary channels related to autocyclic mechanisms.
0.0 Leave the parking lot of the Grand Junction Hilton. Grand Junction , Colorado. Turn left onto Horizon Drive. Pass under the 1-70 bridge, Turn left into the entrance ramp for 1-70 west.
0.2 Enter 1-70 heading west toward the Colorado –Utah State line. For the next 20 miles the Interstate will parallel the Colorado River flowing along the west side of the Grand Valley. The Interstate is built on the gray Cretaceous Mancos Shale. To the west of the Colorado River are the red cliffs of the Colorado National Monument. The Monument is operated by the National Park Service. These cliffs are the eastern edge of the Uncomahgre Uplift. As you drive north along the Interstate, the steeply dipping eastern limb of the Uncomahgre is clearly visible. This tight monoclinal fold is the result of horizontal compressional tectonics associated with Laramide deformation (Heyman, 1983). The red rocks in the Mounment include, from stratigraphically oldest to youngest: the Chinle Formation forming the lower, less resistant slops, the Wingate formation forming the massive cliffs up to 400 feet thick , the Kayenta Formation overlain by an unconformity along which the Navajo and Curtis Formations are missing , the Summerville and Entrada Formations, and the Morrison Formation consisting of fluvial sandstones and associated mudstones, within which some of the earliest dinosaur bones in North America were discovered in the late 19th century. The Jurassic Morrison Formation is unconformably overlain by the brown, Cretaceous, coal-bearing Dakota Sandstone. The Dakota caps many of the high mesas within the Mounment and forms well-exposed dip slopes along the Interstate in the vicinity of the exit to Mack, Co..