--> Abstract: Diagenetic History of the Permian White Rim Sandstone Member, Cutler Formation, Tar Sand Triangle, Paradox Basin, Utah, by P. L. Hansley; #91012 (1992).

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ABSTRACT: Diagenetic History of the Permian White Rim Sandstone Member, Cutler Formation, Tar Sand Triangle, Paradox Basin, Utah

HANSLEY, PAULA L., U.S. Geological Survey, Denver, CO

The Permian White Rim Sandstone Member of the Cutler Formation hosts one of the United States' largest known tar sand deposits (estimates range from 6.3 to 16 billion bbl in place) in southeastern Utah where predominantly eolian White Rim strata dipping gently to the northwest constitute an exhumed stratigraphic trap. Core samples taken from depths of 1402 to 1526 ft contain fine- to medium-grained well-sorted subarkoses characterized by subangular to subrounded quartz and unaltered potassium feldspar. Nonferroan calcite cement precipitated soon after deposition; upon further burial, much of the calcite dissolved. A significant negative correlation between calcite and oil implies that calcite dissolution may have been related to influx of organic acids just prior to oil migration. Abu dant (average 4 vol. %), large quartz overgrowths covered with oil protrude into secondary pores. Lack of framework grain dissolution implies that the authigenic silica may be extrinsic. A significant positive correlation between quartz overgrowths and oil suggests that organo-silica complexing may have been a factor in silica transport. Authigenic dolomite rhombohedra, which are most common in oil-saturated intervals, contain fluorescing oil-bearing inclusions. Under cathodoluminescence, dolomite cores show overgrowth by several generations of ferroan and nonferroan dolomite reflecting changes in groundwater chemistry during diagenesis. Late precipitation of pore-filling kaolinite and oxidation of pyrite associated with the influx of meteoric water during Tertiary uplift and erosion pos dated emplacement of oil.

 

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)