Geology and oil shale resources of the eastern side of the Piceance Creek Basin, Rio Blanco and Garfield counties, Colorado

Abstract

HEJCUHC13 OF THE EA3TEHX PART OF IRK fICSalKK Cfi£XK B43ZB* BIO BLAMCQ AfiD (UBFIEifi oonUina th* rlotooaa ana Baaiii in vsatonr Co foivatlon. T5»^oll »bal«»-crop out <.« >-*. .t.-^^: .-^|i ;: ia proavineot «^ around the argina of the baaiiv and qmfcarlia the I. :-^/^^'?-^^^^'-*^^^-^ "'T^raS/-' e»aia\^p^-'piao«.-«iiiBai^" laaa».than, 1500 feet of or«rburd«n. The r«port« (tttnaliaat>ar» 1923) deacrlb* tb» oU v' l»0r «« »««r part of the baaln (aee ae«capefl7ing Mapa), aereral gaa toat well* a,^^^^ ^^;f^^^^; s^f-^^j^'i^-^ ^"v " '^\*^^^'^ ^iv ^ , , penetrated the complete aequence of oil shale ia the Green Eiver *?/ , [^^^j^f^^-^it^y^^^^ *' ,-,:^:-.'f-^ _« *-*c-u %Jhia report ehcr« tha otiaract^r ani ^^ of the these eubatirfaoo aoationa and in a vurfaee aeotioa-S^-' ^^fe^^;

Geology of the central Roan Plateau area, northwestern Colorado

“…The Anvil Points Member was first used by Donnell (1953, p. 16) to replace the informal name "lower sandy member of the Green River Formation" that had been used on two geologic maps (Duncan and Denson, 1949;Duncan and Belser, 1950). Johnson (1975) used the term Anvil Points Member for these beds in the Long Point quadrangle just south of the report area where they merge laterally into the Garden Gulch Member by a rather abrupt pinchout of the characteristic Anvil Points sandstone beds.…”

The systematic geologic mapping program and a quadrangle-by-quadrangle analysis of time-stratigraphic relations within oil shale-bearing rocks of the Piceance Basin, western Colorado

“…4). These maps, which now represent the most detailed geologic mapping available for the oil shale area in Colorado, (1) largely supersede earlier, less detailed 1:63,360-scale mapping around the west, south, and east margins of the basin published in the late 1940s and early 1950s (Duncan and Denson, 1949;Duncan and Belser, 1950;Waldron and others, 1951;Donnell and others, 1953) and (2) extend the larger scale, detailed mapping into the previously unmapped central and northern parts of the basin.…”

“…In addition, much of the Green River Formation tends to weather white due to its high carbonate content, making it difficult to distinguish different lithologies from a distance. As a result, mapping in these areas, including the 1:62,500-scale mapping published in the late 1940s and early 1950s (Duncan and Denson, 1949;Duncan and Belser, 1950;Donnell and others, 1953) and the more recent 1:24,000-scale mapping, relied heavily on stratigraphic sections typically measured and described along the end of ridges, where access is relatively less difficult. However, measured sections, some of the more detailed of which were published along with the geologic maps, had to be as closely spaced as possible to pick up the subtle lateral facies changes.…”

X-ray mineralogy of the Parachute Creek Member, Green River Formation, in the northern Piceance Creek basin, Colorado

“…48). Duncan and Belser (1950) reported a thin Douglas Creek Member in the subsurface as far northeast as the Piceance Creek gas field. The Douglas Creek Member conformably overlies the Wasatch Formation and is conformably overlain by the Garden Gulch Member.…”

“…53) chose the lower contact of the Parachute Creek Member at about the same stratigraphic position as we did. Duncan and Belser (1950) placed the contact at the top of sandstone beds (our units 25 and 27 in the Bio Blanco section) about 270 feet above the base we chose for the Parachute Creek (D. C. Duncan, oral commun., 1970). Thus, they seemed to have a thinner Parachute Creek Member only 445 feet thick as compared with 735 feet measured by Donnell (1961, pi.…”