White Rim Sandstone Research Articles

Density-Driven Convection for CO2 Solubility Trapping in Saline Aquifers: Modeling and Influencing Factors

Industrial development has significantly increased the concentration of CO2 in the atmosphere, resulting in the greenhouse effect that harms the global climate and human health. CO2 sequestration in saline aquifers is considered to be one of the efficient ways to eliminate atmospheric CO2 levels. As an important mechanism, the solubility trapping greatly determines the efficiency of CO2 sequestration in saline aquifers, and this depends, in turn, on the density-driven convection that occurs during the sequestration. Density-driven convection is influenced by multiple factors. However, existing discussions on some of these influential factors are still ambiguous or even reach contradictory conclusions. This review summarizes the common modeling approaches and the influence of factors on density-driven convection. We suggest that saline aquifers with high values of depth, permeability, pH, and SO2 impurity concentration are the ideal CO2 sequestration sites. A certain degree of porosity, fractures, stratification, slope, hydrodynamic dispersion, background flow, and formation pressure are also considered advantageous. Meanwhile, the geological formation of the Permian White Rim Sandstone or carbonate is important, but it should not contain brine with excessive viscosity and salinity. Finally, we discuss the contents in need of further research.

Sedimentology, diagenesis, and reservoir characterization of the Permian White Rim Sandstone, southern Utah: Implications for carbon capture and sequestration potential

Rising CO2 emissions have caused scientists and policy makers to explore potential solutions to reduce atmospheric CO2 levels, including carbon capture and sequestration. This project, funded through the Department of Energy CarbonSAFE initiative, aims to characterize the potential storage capacity and preferential fluid-flow pathways through the Permian White Rim Sandstone on and near the San Rafael Swell, Utah, to assess the formation’s viability as a possible CO2 sequestration reservoir. A diverse suite of sedimentological observations and diagenetic analyses was used to assess the White Rim Sandstone’s reservoir potential, including detailed outcrop observations, facies descriptions and ichnology, measured stratigraphic sections with associated correlations, permeability measurements, thin-section petrography, and visible and near-infrared spectroscopy. Stratigraphically, the White Rim Sandstone has two major units separated by a marine transgressive surface. The lower eolian unit is characterized by decimeter- to meter-scale trough cross-bedded grain-flow and wind-ripple facies. The upper reworked, shallow-marine unit has a consistent set of facies at all three field sites: (1) soft-sediment deformation facies (e.g., contorted bedding or clastic pipes), (2) symmetric ripple laminations, (3) bioturbated (dominantly horizontal), and (4) bioturbated (dominantly vertical). This set of four facies represents the transgression of the Permian Kaibab sea over the Permian White Rim coastal dune field. The outcrop samples and subsurface core samples (∼1561–2243 m deep and ∼33–50 km away from the outcrop localities) experienced different diagenetic fluid-flow histories that drastically impacted the reservoir properties. Outcrop samples have initial quartz overgrowth cements followed by rim-forming calcite cements, iron oxide cements, and occasional oil staining. In contrast, the core samples show significant compaction, followed by quartz overgrowth cementation and a later stage of patchy, large, pore-filling calcite cement that eliminated the porosity and permeability of the potential reservoir (<0.1 md). Outcrop permeability values tend to reflect textural differences in facies, particularly the presence and spacing of internal laminations and bounding surfaces. Facies with fewer internal laminations, such as the grain-flow facies, have higher permeability values than facies with closely spaced internal laminae, such as the wind-ripple facies. Disruption of original bedding (e.g., soft-sediment deformation or bioturbation) alters original depositional textures and creates preferential flow pathways with the potential to increase permeability. Overall, if the diagenesis and resulting low permeability values of the core samples are representative of the White Rim Sandstone at depth, then the White Rim Sandstone would not make a high-quality storage reservoir despite initial, promising outcrop results.

Provenance of a Permian erg on the western margin of Pangea: Depositional system of the Kungurian (late Leonardian) Castle Valley and White Rim sandstones and subjacent Cutler Group, Paradox Basin, Utah, USA

Consideration of petrographic and U-Pb provenance data and paleocurrent analysis of Kungurian (upper Leonardian) Cutler Group strata in the salt anticline province of the Paradox Basin of Utah demonstrates striking contrasts in composition and inferred sources of stratigraphically adjacent eolian and fluvial facies. Eolian strata, termed here the Castle Valley Sandstone, exposed in the Castle Valley northeast of Moab, Utah, and long correlated with the White Rim Sandstone, were deposited on the southwestern flank of a NW-trending diapiric salt wall. The eolian strata, which overlie red fluvial sandstone and conglomerate of the undifferentiated Cutler Formation, are as much as 183 m thick in outcrop and consist of two eolianite members separated by a thin sheet-flood deposit that contains pebbles derived from the salt wall and upturned conglomeratic strata adjacent to it. Both eolian and underlying fluvial deposits thin and onlap eastward onto the now-collapsed salt wall. Fluvial strata at Castle Valley and in exposures to the northeast were transported northwestward, parallel to the salt wall. Large-scale foresets in the lower eolianite member indicate dominant northeasterly wind directions (present coordinates) and transport directly away from the contemporary Uncompahgre uplift, whereas foresets in the upper member indicate variable northeasterly and northwesterly paleowinds. The eolian strata thus accumulated on the lee side of the salt wall, but sandstone composition and northwesterly wind components indicate net transport from the northwest, comparable with dominant southeastward sand transport, away from the Pangean shoreline, documented for the greater White Rim erg to the west and northwest. The NW and NE winds are both predicted by late Paleozoic atmospheric circulation models for western Pangea.

Hydrocarbon-induced diagenetic alteration of the Permian White Rim Sandstone, Elaterite Basin, southeast Utah

The Permian White Rim Sandstone is a partly exhumed, primary reservoir of the Tar Sand Triangle accumulation in southeastern Utah. In the Elaterite Basin (Canyonlands National Park and Glen Canyon National Recreation Area), the White Rim Sandstone is well exposed and varies in color from white to red, orange, and brown. Superimposed on eolian and marine deposits are three diagenetic facies that impart the coloration and are defined by iron oxide cement concentration as (1) bleached white (low iron), (2) diffuse (moderate iron), and (3) concretionary (concentrated iron). A yellow alteration aureole of bleaching extends up to 10 m (32 ft) into the underlying Organ Rock Shale and up to 20 m (65 ft) into the overlying Moenkopi Formation. These formations surround the White Rim reservoir as fine-grained seals. Field, petrographic, and geochemical analyses indicate that the White Rim Sandstone records three major diagenetic stages. (1) The reservoir underwent oxidation, which led to the precipitation of thin iron grain coatings. (2) Hydrocarbon migration through the reservoir removed early grain coatings and reprecipitated disseminated and concentrated pyrite cement. (3) The pyrite was later altered to hematite or goethite by oxidizing fluids. In conventional petroleum exploration, the timing of hydrocarbon migration is often difficult to resolve. This study utilizes the record of mobilized and reprecipitated iron as a tool to constrain interpretations of the timing of hydrocarbon migration relative to seal and trap emplacement. This study has broad application as an exploration tool for deciphering fluid flow in similar clastic reservoirs.

Simulation of reactive transport of injected CO 2 on the Colorado Plateau, Utah, USA

This paper investigates injection of CO 2 into non-dome-shaped geological structures that do not provide the traps traditionally deemed necessary for the development of artificial CO 2 reservoirs. We have developed a conceptual and two numerical models of the geology and groundwater along a cross-section lying approximately NW–SE and in the vicinity of the Hunter power station on the Colorado Plateau, Central Utah and identified a number of potential sequestration sites on this cross-section. Preliminary modeling identified the White Rim Sandstone as appearing to offer the properties required of a successful sequestration site. Detailed modeling of injection of CO 2 into the White Rim Sandstone using the reactive chemical simulator ChemTOUGH found that 1000 years after the 30 year injection period began approximately 21% of the injected CO 2 was permanently sequestered as a mineral, 52% was beneath the ground surface as a gas or dissolved in the groundwater and 17% had leaked to the surface and leakage to the surface was continuing.

Dike formation, cataclastic flow, and rock fluidization during impact cratering: an example from the Upheaval Dome structure, Utah

Patterns of deformation within the Upheaval Dome structure, Utah, provide important clues for assessing its possible impact origin. The complex structure of the innermost part of the dome, in particular of the White Rim Sandstone (WRS), indicated almost complete loss of internal coherence during deformation. The WRS displays extreme thickness variations, blind terminations and frequent embranchments at nodular-like points. This, together with discordant contacts to the country rock, shows that WRS builds up a dike network that was emplaced and injected during formation of the central dome. Microstructural analysis reveals that the macroscopically ductile appearance is achieved by distributed cataclastic flow. Beside intergranular fracturing, dislocation pile-ups, dislocation arrays and tangles indicate additional dislocation glide activity in quartz of WRS during deformation. Disseminated brittle fault zone networks postdate the cataclastic flow and represent the final deformation increments during formation of the central uplift. The distributed cataclastic flow in the sandstones was initiated by grain crushing, collapse of pore space, and subsequent intergranular shear. In accordance with experimental data for a similar sandstone (Berea sandstone), it is suggested that a high effective confining pressure, most likely in excess of 250 MPa, was necessary to cause this flow. At shallow crustal levels (maximum possible depth of burial of WRS is 3 km) such a high confining pressure can only be build up dynamically by impact processes. From deformation mechanisms, a shock wave attenuation to magnitudes below the Hugoniot elastic limit of quartz can be deduced and correlates with a burial of the studied sediments of 2–3 km at the time of the impact.

The Search for a Source Rock for the Giant Tar Sand Triangle Accumulation, Southeastern Utah

A large proportion (about 36%) of the world’s oil resource is contained in accumulations of heavy oil or tar. In these large deposits of degraded oil, the oil in place represents only a fraction of what was present at the time of accumulation. In many of these deposits, the source of the oil is unknown, and the oil is thought to have migrated over long distances to the reservoirs. The Tar Sand triangle in southeastern Utah contains the largest tar sand accumulation in the United States, with 6.3 billion bbl of heavy oil estimated to be in place. The deposit is thought to have originally contained 13-16 billion bbl prior to the biodegradation, water washing, and erosion that have taken place since the middle-late Tertiary. The source of the oil is unknown. The tar is primarily contained within the Lower Permian White Rim Sandstone, but extends into permeable parts of overlying and underlying beds. Oil is interpreted to have migrated into the White Rim sometime during the Tertiary when the formation was at a depth of approximately 3500 m. This conclusion is based on integration of fluid inclusion analysis, time-temperature reconstruction, and apatite fission-track modeling for the White Rim Sandstone. Homogenization temperatures cluster around 85-90°C for primary fluid inclusions in authigenic, nonferroan dolomite in the White Rim. The fluid inclusions are associated with fluorescent oil-bearing inclusions, indicating that dolomite precipitation was coeval with oil migration. Burial reconstruction suggests that the White Rim Sand stone reached its maximum burial depth from 60 to 24 Ma, and that maximum burial was followed by unroofing from 24 to 0 Ma. Time-temperature modeling indicates that the formation experienced temperatures of 85-90°C from about 35 to 40 Ma during maximum burial. Maximum formation temperatures of about 105-110°C were reached at about 24 Ma, just prior to unroofing. Thermal modeling is used to examine the history of potential source rocks for the White Rim oil. The most attractive potential sources for White Rim oil include beds within one or more of the following formations: the Proterozoic Chuar Group, which is present in the subsurface southwest of the Tar Sand triangle; the Mississippian Delle Phosphatic Member of the Deseret Limestone and equivalent formations, the Permian Kaibab Limestone, the Sinbad Limestone Member of the Triassic Moenkopi Formation, and the Jurassic Arapien Shale, Twin Creek Limestone, and Carmel Formation, which are present west of the Tar Sand triangle; the Pennsylvanian Paradox Formation in the Paradox basin east of the Tar Sand triangle; and the Permian Park City Formation northwest of the Tar Sand triangle. Each formation has a high total organic carbon content and is distributed over a wide enough geographic area to have provided a huge volume of oil. Source beds in all of the formations reached thermal maturity at times prior to or during the time that migration into the White Rim is interpreted to have occurred. Based on all available data, the most likely source for the Tar Sand triangle appears to be the Mississippian Delle Phosphatic Member of the Deseret Limestone. Secondary migration out of the Delle is interpreted to have occurred during the Cretaceous, during Sevier thrusting. Subsequent tertiary migration into the Tar Sand triangle reservoir is interpreted to have occurred later, during middle Tertiary Laramide deformation.

Changes in Rate of Transgression Across the Permian White Rim Sandstone, Southern Utah

ABSTRACT A change in the rate of transgression of the Permian Kaibab sea across southern Utah is proposed on the basis of stratal relations and preserved paleotopography in the Permian White Rim Sandstone. As the Kaibab sea transgressed southern Utah, across a generally west-dipping continental margin, the rate of transgression increased. Interbedded coastal dune sandstones (White Rim Sandstone) and marine carbonates (Kaibab limestone) reflect slow transgression across what is now south-central Utah. Preserved paleotopography and the absence of intertonguing of carbonates and sandstones in southeastern Utah reflects a more rapid transgression, indicating that the rate of sea-level rise increased with time. Throughout the transgression, relative rise in sea level was discontinuous, and punctuat d by stillstands. In general, intervening stillstands decreased in duration as the transgression progressed. This change in transgression rate can be interpreted in one of two ways: rate of regional sea-level rise across southern Utah increased with time, or previously unrecognized and localized subsidence occurred in eastern Utah during Kaibab transgression. Although regional tectonism is important, we favor the former interpretation because no independent evidence of local tectonic movement can be found.

Palaeo‐yardangs: wind‐scoured desert landforms at the Permo‐Triassic unconformity

ABSTRACTIn Canyonlands National Park, south‐east Utah, at least 29 partly exhumed, aligned sandstone ridges trending generally N20°W occur at the upper unconformable surface of the Lower Permian (Leonardian) White Rim Sandstone. The ridges are at least 1·5 km long, 250 m wide and have up to 14 m of vertical relief (mean of 9 m). A thin lag of coarse sandstone that contains wind‐ripple laminae and granule ripples directly overlies the ridges. Angular blocks of sandstone within the lag and sand‐filled fissures immediately below the lag, within the ridges, attest to early cementation of the ridge‐forming material. SE‐dipping aeolian cross‐strata within the White Rim Sandstone and within the lag closely parallel the ridge trend. The ridges are interpreted as wind‐sculpted desert landforms (yardangs) that developed on the lithified upper surface of the White Rim Sandstone during an extended period of hyperaridity towards the end of the Permian.

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

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

Unconformity Related Traps and Production, Lower Cretaceous Through Mississippian Strata, Central and Northern Rocky Mountains: ABSTRACT

Unconformities provide a useful means of equating stratigraphic traps between basins. Systematic mapping can define new concepts through analogy, often from geographically separate areas. Lower Cretaceous through Mississippian surfaces in the central and northern Rockies provide examples. Late Mississippian and Early Pennsylvanian surfaces formed at least four paleodrainage basins separated by the Transcontinental arch. Tyler Formation valley fills (Montana, North Dakota) have produced more than 100 million BOE. Analogous targets in Utah remain untested, but the Mid-Continent Morrow trend continues to yield new reserves. Permian and Triassic paleodrainages filled primarily with seals and form regional traps. A breached Madison trap (Mississippian, Colorado), more than 350 million BOE (Permian Minnelusa, Wyoming), more than 8 billion BOE (from the White Rim Sandstone tar deposits Permian Utah), and eastern Williston basin (Mississippian) are examples. Minor basal valley fill trapping also occurs. Transgressive carbonate facies changes have trapped more than 40 million BOE (Permian Phosphoria Formation, Wyoming). Additional deep gas potential exists. Jurassic unconformities control seal distribution over Nugget Sandstone (Jurassic) reservoirs and partially control Mississippian porosity on the Sweetgrass arch (Montana). Minor paleohill trapping also occurs. Lower Cretaceous surfaces have trapped nearly 2 billion BOE hydrocarbons in 10 paleodrainage networks. Undrilled paleodrainage basinsmore » remain deep gas targets. The systematic examination of Rocky Mountain unconformities has been understudied. New exploration concepts and reserve additions await the creative interpreter.« less

Erg margin of the Permian White Rim Sandstone, SE Utah

ABSTRACTThe Permian White Rim Sandstone of the Canyonlands National Park, Utah, contains a wide variety of sedimentary structures and features that largely result from stages in erg migration and marine influence on an erg margin. Three spatially distinct lithological and depositional facies are recognized and can be distinguished as informal units within the formation. The aeolian dune facies is composed predominantly of fine‐grained cross‐stratified sandstone of the White Rim erg. This facies is the most widespread and comprises the bulk of the formation. Within the aeolian dune facies are small subfacies that represent interdune deposits. A sheet sand facies, composed of parallel‐bedded sandstone, makes up a significant part of the lowest part of the White Rim Formation. This facies appears to have been the precursor or leading (progradational) edge to the main erg system. The final facies is a reworked or veneer facies of rippled to disturbed sandstone that is localized in its extent. It is restricted to the upper few metres of the formation and is transitional in some places to the Triassic Moenkopi Formation. This veneer facies contains many structures which indicate marine reworking as well as periods of desiccation or subaerial exposure.Some previous interpretations of the White Rim Sandstone have tended to classify the whole formation as one depositional setting. It is clear that at the margin of a sand sea, as shown in the White Rim Sandstone, there are transitional facies due to the interactions with other environments. Additionally, variation in the stratigraphic relationships of facies can be related to stages of erg migration. Erg margin deposits preceded central erg development. Erg initiation occurred during a probable relative sea level low. Sea level influence is recorded at the top of the formation because erg termination accompanied a relative sea level high with cut‐off of sand supply. Transgression of the Permian Kaibab Sea over the White Rim erg was probably the main process in preservation of original dune topographic relief. Sea level fluctuations also may have affected distribution of facies and the complexities of structures at the erg margin. Subsequent fluvial reworking of the veneer facies may have obliterated Late Permian features during lowest Triassic Moenkopi deposition.

Coastal dune facies, Permian Cutler Formation (White Rim Sandstone), Capitol Reef National Park area, southern Utah

The Permian Cutler Formation (White Rim Sandstone) in the Capitol Reef National Park area in southern Utah is an excellent example of a coastal dune complex subjected to periodic flooding by marine waters. Wind-ripple, grainfall and grainflow laminae compose the cross-sets deposited by eolian dunes. However, wave-reworked structures such as oscillation ripples, the occurrence of the characteristically marine trace fossils Thalassinoides and Chondrites, and interfingering marine carbonate beds of the Kaibab Formation collectively indicate marine interaction with the eolian environment. Four facies are distinguished: cross-stratified sandstone, burrowed to bioturbated sandstone, brecciated and deformed sandstone, and ripple-laminated sandstone and thin carbonate beds. One unusual aspect of the cross-stratified sandstone facies is the abundance of coarse-grained sand. Coarse-grained sand is atypical in many ancient eolian slipface deposits, but occurs here in large slipface foresets as both grainflow and wind-ripple deposits. No water-laid structures are found in these slipface deposits. Coarse-grained sand was probably transported to the Cutler shoreline by fluvial systems draining the Uncompahgre Uplift to the east, and then concentrated as coarse-grained ripples in interdune areas. Some of these coarse-grained ripples migrated up the stoss side of the dunes and accumulations of coarse-grained sand avalanched down the crest to form grainflow deposits. An extensive amount of soft-sediment deformation is indicated by the presence of convolute bedding and brecciation. These features occur near the zone of interfingering with marine carbonate beds of the Kaibab Formation. The water-saturated and moist conditions required for extensive deformation may have been controlled by the proximity of these sandstones to the shoreline, and fluctuations in the associated groundwater table.

White Rim Trail, Island in the Sky: ERRATUM

The cover photograph by Jacqueline E. Hunton for the January 1988 (v. 72) AAPG Bulletin should have read: Rim Trail, Island in the Sky. View of top of cliff-forming White Rim Sandstone (Permian) and Green River from top of Junction Butte, Canyonlands National Park, Utah. Photography by Jacqueline E. Huntoon, Pennsylvania State University, University Park, Pennsylvania. End_of_Article - Last_Page 647------------

Marine Origin of Paleotopographic Relief on Eolian White Rim Sandstone (Permian), Elaterite Basin, Utah

The tar-bearing Permian White Rim Sandstone in the Elaterite basin near Canyonlands National Park, Utah, is an example of an exhumed paleotopographic high (paleohigh) with approximately 250 ft (76 m) of relief. Accumulations of heavy hydrocarbons are concentrated along the axis of the high. Eolian processes controlled deposition of most of the White Rim Sandstone, and the action of erosional marine processes modified preexisting dune relief at the top of this sandstone. The interaction of these depositional processes is evidenced by the distinction of two informal units within the White Rim Sandstone. The lower unit is an eolian facies that comprises most of the formation. This unit is characterized by prominent, large-scale, high-angle cross-stratification; ripples with high ripple indices; and eolian ripple (translatent) strata. The upper unit is a thin marine facies with oscillation (wave) ripples, fluid-escape structures, megapolygons, and rip-up clasts of the lower unit. The eolian and marine facies are separated by a sharp erosional boundary. The basic form of the paleohigh is the result of sedimentation within an eolian dune field, but much of the study area's unusual paleotopographic relief is attributed to erosion and reworking of the lower unit during a major marine transgression. The upper marine facies of the White Rim was also deposited during this transgression. Six different wave-cut terrace levels on the flanks of the elongate high record a discontinuous rise of sea level during the transgression. Megapolygons within the upper unit resulted from desiccation and expansive salt-crystal growth when the area became subaerially exposed during a regression at the end of the Permian. The paleohigh was eventually mantled by fine-grained sediments of the Triassic Moenkopi Formation. The Moenkopi cover effectively protecte the delicate features of the paleohigh now exposed by Holocene erosion in the Elaterite basin. The depositional and preservational model for the White Rim Sandstone proposed here may be a useful analog to other stratigraphic traps associated with paleotopographic relief.

The Permian-Triassic Stratigraphy of the Northwest Paradox Basin Area, Emery, Garfield, and Wayne Counties, Utah

The Upper Permian and Lower Triassic rocks in the northwestern Paradox basin are closely related even though they are separated by a significant unconformity. Careful analysis of surface and subsurface data provides a framework to relate underlying units to deposition of suprajacent units. The Black Dragon Member of the Triassic Moenkopi Formation infilled the topography on the underlying Permian units. The thickness of the Black Dragon Member is inversely related to the thickness of the underlying White Rim Sandstone. The upper portion of the Black Dragon Member was deposited primarily in coastal marine environments with a very low westward depositional slope. An oolite-bearing carbonate shelf present during subsequent Sinbad Member deposition was also controlled, in part, by thickness distribution of the Permian White Rim Sandstone. The Torrey Member was deposited on the Sinbad Member in a fine-grained, elastic-dominated, low energy, very flat coastal environment. The Moody Canyon Member (uppermost Moenkopi) was deposited in a subaqueous environment, probably marine. The Emery uplift, a pre-White rim tectonic element, did not affect deposition of the White Rim, Kaibab or Moenkopi strata. The San Rafael Swell is a Laramide tectonic feature that is offset from and unrelated to the Emery uplift or deposition of the Permian and Triassic units.

Hydrocarbon Potential in Paradox Basin: an Overview: ABSTRACT

The petroleum-rich Paradox basin of southeastern Utah and southwestern Colorado remains an exploration frontier. With current production and exploration programs focusing on algal mound limestones in the Pennsylvanian Paradox Formation and deeper Mississippian structures, numerous other zones with hydrocarbon potential exist. Floored by a complexly faulted Precambrian basement, there is ample evidence suggesting that both source beds and reservoir rocks comprise much of the Cambrian section underlying the region. Although successfully developed at Lisbon field, Devonian sandstones and Mississippian carbonates have only been peripherally explored in other parts of the basin and much remains to be learned about deeper evaporite sequences in the Paradox Formation where tur idite deposits are known or inferred to exist between source bed shales and dolomites. Migration reservoirs exist in the Laramide structures that rim and occupy parts of the basin. Permian tar sand deposits estimated to hold 4-8 billion bbl of oil in place remain to be developed where an exhumed stratigraphic trap in the White Rim Sandstone is exposed west of the confluence of the Colorado and Green Rivers. Additionally, carbon dioxide gas deposits associated with Tertiary intrusives in the region require further delineation and development for coal slurry and enhanced oil recovery projects. Accordingly, the basin is expected to continue being developed for its resources for several decades. End_of_Article - Last_Page 848------------

Permian Paleotopography and Depositional Patterns--White Rim Sandstone, Elaterite Basin, Southeast Utah: ABSTRACT

The Permian White Rim Sandstone in the Elaterite basin (Canyonlands National Park) exhibits an unusual paleotopographic relief. The mapped portion of the exposed top of the formation indicates that the paleotopography has a prolate configuration in plan view. The major axis and crest of the relief trends N09°E. In cross section, the paleotopography is convex upward. The flanks of the structure are slightly terraced with two main levels. Dip angles on the flanks range from 0° to 16°, with the more gentle slopes located toward the crest of the topographic high and generally steepening as the structure disappears into the subsurface. The sedimentary structures and stratigraphy in the 1-5.3 m (3-17.4 ft) upper veneer of the White Rim Sandstone indicate that the topography was affected by marine wave processes in the Elaterite basin. Small-scale features in the basal contact of the veneer include scours up to 15 cm (6 in.) deep, sharp steplike cuts up to 45 cm (18 in.) deep, and rip-ups of the lower eolian part of the White Rim Sandstone averaging 30 cm (12 in.) in diameter. Lateral changes in structures and lithologic characteristics indicate that southwest of the Elaterite basin the veneer was deposited in a fluvial environment. The form of the paleotopographic high in the Elaterite basin is practically inherited from an eolian dune field. The uneven base and presence of chert pebbles in the veneer indicate erosion of Permian highs and an unconformable contact between the lower eolian and upper veneer of the White Rim Sandstone. Deposition of the veneer and partial reworking of the topography occurred during a marine transgression at the Permian-Triassic boundary. End_of_Article - Last_Page 938------------

Tar Sand Triangle--Largest United States Tar Sand Deposit: ABSTRACT

Estimates of 4-8 billion bbl of oil in place make the Tar Sand Triangle the largest known deposit of tar sand in the United States. At present, 14 different companies or individuals hold leases in the area, most of which are for in-situ development of the tar sand resource. In the summer of 1982, the DOE/LETC drilled four core holes, three of which penetrated the principal bitumen-bearing sequence--the White Rim Sandstone. The locations of the core holes were selected to fill obvious gaps in the data available from previous holes drilled into or through the deposit. End_of_Article - Last_Page 935------------

Complex Interaction of Eolian and Marine Sedimentation in Permian White Rim Sandstone, Elaterite Basin, Southeast Utah: ABSTRACT

Two depositional units distinguished in the Permian White Rim Sandstone of the Elaterite basin indicate episodes of both eolian and marine sedimentation. The lower unit is a thick section of large-scale, high-angle, cross-bedded quartzarenite. The tabular cross-bed sets average 2.6 m (8.5 ft) in height and contain inversely graded translatent strata and small ripple trains with high ripple indices. Some exposures reveal large barchan dune forms. This lowest unit comprises most of the formation and is sharply cut and scoured by the overlying unit. The upper unit is a thin veneer that ranges from 1 to 5.3 m (3 to 17 ft) in thickness and possesses End_Page 934------------------------------ characteristic marine structures. An idealized vertical sequence within the veneer consists (in ascending order) of a laminated sandstone facies (in places containing chert pebbles), cross-stratified (0.3-m or 1-ft sets) sandstone facies, and an oscillation ripple sandstone facies. The upper part of the oscillation ripple sandstone facies may contain 6-sided polygonal structures filled with coarse-grained sandstone and chert pebbles, or it may be covered by a massive facies that contains abundant fluid-escape structures. Variations on the idealized veneer stratigraphy exist where some facies are absent, but the vertical sequence order is maintained. Most of the formation is interpreted to be eolian in origin. Northerly winds deposited the large cross-bed sets in an extensive dune field. This event was followed by a period of marine transgression that reworked the uppermost part of the formation and formed the thin veneer. The abundance of fluid-escape structures and oscillation ripples in the veneer indicates rapid deposition by marine processes. The distinctive stratigraphy within the veneer reflects a deepening trend with the rising transgression. End_of_Article - Last_Page 935------------