Stratigraphic sections of the upper Mancos Shale-lower Mesaverde Formation interval along the Grand Hogback between Rifle Gap and North Thompson Creek, Garfield and Pitkin counties, Colorado

Gill, James R.; Freeman, Val L.

doi:10.3133/ofr78178

Cited by 1 publication

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“…Mapping in the central Grand Hogback has shown that the Rollins Sandstone Member at New Castle (Warner, 1964) can be traced to the Cozzette Sandstone Member of Warner (1964) Sandstone Member, which is 300-450 ft (91-137 m) higher in the Iles Formation. These correlations are illustrated on plates 1 and 2, and on figure 28, and they differ from established correlation of the Rollins and Trout Creek Sandstone Members of Warner (1964), 24.5 mi {39 km) SE North Thompson Creek (Gill and Freeman, 1978) Rollins Sandstone Member (Warner, 1964) ?--------------------------- (Gill and Cobban, 1966, pl. 2) and difference in thickness of Upper Cretaceous strata between that area and Grand Hogback area (McGookey and others, 1972, p. 207).…”

Section: Sandstone-member Correlationsmentioning

confidence: 76%

“…Direction of shoreline migration X Measured section-From Gaffke (1979). Gill and Freeman (1978), and this report ME Maximum extent of coal-bearing deposits Vegetation FIGURE 22.-Schematic sketch of coastal paleogeography during deposition of Trout Creek Sandstone Member, based on surface data from Grand Hogback (Madden, 1983 and this report) and Routt County (Gaffke, 1979) and extrapolated to adjacent areas of western and northwestern Colorado. Outline of coast is modified from Boyles and others (1981, fig.…”

Section: Lower Part Of Haas Sandstone Unit Williams Fork Formationmentioning

confidence: 99%

“…In the southern part of the basin the Cozzette shows a "nearly constant relationship to E. jenneyi," and the sandstone locally is overlain by phosphate nodules in both the Woody Creek quadrangle (V .L. Freeman, written commun., 1984) and in North Thompson Creek (Gill and Freeman, 1978). Warner (1964) retained the name Trout Creek in Rifle Gap for the thick, white sandstone traced by surface correlations from its type locality on Trout Creek in the Yampa coal field southwestward to the central Grand Hogback (Gale, 1906(Gale, , 1907(Gale, , 1910Hancock, 1925;Hancock and Eby, 1930;Burbank and others, 1935;Horn and Gere, 1959;Tweto, 1979).…”

Section: Sandstone-member Correlationsmentioning

confidence: 99%

“…20) because of the abundant oyster fragments which occur in outcrop above the Cozzette Sandstone Member of Warner (1964) in Rifle Gap. The approximate maximum seaward extent of the Cozzette delta plain is based upon the maximum southeastward extent of the Wheeler coal bed along the Grand Hogback (Gill and Freeman, 1978) and the occurrence of E. jenneyi above the Cozzette Sandstone Member of Warner ( 1964) in North Thompson Creek.…”

Section: Cozzette Sandstone Member Iles Formationmentioning

confidence: 99%

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Stratigraphy, depositional environments, and paleogeography of coal-bearing strata in the Upper Cretaceous Mesaverde Group, central Grand Hogback, Garfield County, Colorado

Madden-McGuire¹

1989

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Marine and nonmarine strata in the upper part of the Iles and lower part of the Williams Fork Formations of the Mesaverde Group form the richest coal section between Rifle Gap and New Castle, Colorado. Within these strata, the ammonites Exiteloceras jenneyi and Didymoceras cheyennense indicate a late Campanian age for the section, which is 1,000-1,400 feet (305-430 meters) thick. This study distinguishes formal members, the Trout Creek Sandstone Member and Cozzette Sandstone Member of Young (1982) of the Iles Formation, and new informal units. Unit contacts coincide with horizons separating offshore marine, and fresh to brackish-water nonmarine strata. Differences in paleosalinity are indicated by marine mega-and microfossils, and great trace-fossil diversity; brackish-water gastropods and pelecypods (some occurring in bioturbated intervals); and fresh-water gastropods.Sedimentary structures provided evidence for reconstructing paleobathymetry. Outer-offshore deposits are structureless silty mudstone, bearing grain-lined tubes of Terebellina; inner-offshore deposits are storm-deposited, scour-based, hummocky-bedded sandstone, and silty mudstone, locally bearing a diverse trace-fossil assemblage. Shoreface sandstone contains low-angle trough crossbedding and Ophiomorpha.Seven depositional cycles are recorded in the stratigraphic section. Each of these cycles, from base to top, consists of offshore, shoreface, and onshore delta-plain strata. The latter are fluvial deposits with minor coal and brackish-water bayfill.Paleocurrent data indicate that shoreline-normal storm scour occurred in the offshore; shoreline-parallel sand transport to the south occurred in the shoreface; and seaward sediment transport occurred onshore. Coastal deposition was controlled by deltas supplying sediment to shallow, longshore-migrating, bar-trough systems. Delta shifting resulted in interfingering of marine and nonmarine.strata and in shoreline realignments recorded by paleocurrent indicators.New correlations of marine-sandstone members of the upper part of the Iles Formation along the central Grand Hogback presented here are based on field mapping. The sandstone commonly referred to as the Cozzette Sandstone Member in Rifle Gap can be traced to the Rollins Sandstone Member at New Castle, where the sandstone is overlain by the Wheeler coal bed. This interpretation differs from previous correlation of the Trout Creek Sandstone Member in Rifle Gap with the Rollins Sandstone Member at New Castle. The new interpretation presented here suggests that the Trout Creek and Manuscript approved for publication, March 23, 1988. Rollins sandstones are separated by 310-450 feet (94-135 meters) of strata along the central Grand Hogback, with the Rollins lying stratigraphically below the Trout Creek. The new correlation of these marine-sandstone members influences the paleogeographic reconstruction of the local, late Campanian shoreline.2 UPPER CRETACEOUS MESAVERDE GROUP, GRAND HOGBACK, COLORADO Outcrop of Mesaverde Group and equivalent strata O Locat...

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Section: Sandstone-member Correlationsmentioning

confidence: 76%

Section: Lower Part Of Haas Sandstone Unit Williams Fork Formationmentioning

confidence: 99%

Section: Sandstone-member Correlationsmentioning

confidence: 99%

Section: Cozzette Sandstone Member Iles Formationmentioning

confidence: 99%

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Stratigraphy, depositional environments, and paleogeography of coal-bearing strata in the Upper Cretaceous Mesaverde Group, central Grand Hogback, Garfield County, Colorado

Madden-McGuire¹

1989

Professional Paper

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Stratigraphic sections of the upper Mancos Shale-lower Mesaverde Formation interval along the Grand Hogback between Rifle Gap and North Thompson Creek, Garfield and Pitkin counties, Colorado

Cited by 1 publication

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Stratigraphy, depositional environments, and paleogeography of coal-bearing strata in the Upper Cretaceous Mesaverde Group, central Grand Hogback, Garfield County, Colorado

Stratigraphy, depositional environments, and paleogeography of coal-bearing strata in the Upper Cretaceous Mesaverde Group, central Grand Hogback, Garfield County, Colorado

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