East Kaibab Monocline Research Articles

Asymmetry of weathering‐limited hillslopes: the importance of diurnal covariation in solar insolation and temperature

AbstractHillslope asymmetry, i.e. variation in hillslope form as a function of slope aspect and/or mean solar insolation, has been documented in many climates and geologic contexts. Such patterns have the potential to help us better understand the hydrologic, ecologic, and geomorphologic processes and feedbacks operating on hillslopes. Here we document asymmetry in the fraction of hillslope relief accommodated by cliffs in weathering‐limited hillslopes of drainage basins incised into the East Kaibab Monocline (northern Arizona) and Raplee Ridge Monocline (southern Utah) of the southern Colorado Plateau. We document that south‐ and west‐facing hillslopes have a larger proportion of hillslope relief accommodated by cliffs compared with north‐ and east‐facing hillslopes. Cliff abundance correlates positively with mean solar insolation and, by inference, negatively with soil/rock moisture. Solar insolation control of hillslope asymmetry is an incomplete explanation, however, because it cannot account for the fact that the greatest asymmetry occurs between southwest‐ and northeast‐facing hillslopes rather than between south‐ and north‐facing hillslopes in the study sites. Modeling results suggest that southwest‐facing hillslopes are more cliff‐dominated than southeast‐facing hillslopes of the same mean solar insolation in part because potential evapotranspiration rates, which control the soil/rock moisture that drives weathering, are controlled by the product of solar insolation and a nonlinear function of surface temperature, together with the fact that southwest‐facing hillslopes receive peak solar insolation during warmer times of day compared with southeast‐facing hillslopes. The dependence of water availability on both solar insolation and surface temperature highlights the importance of the diurnal cycle in controlling water availability, and it provides a general explanation for the fact that vegetation cover tends to exhibit the greatest difference between northeast‐ and southwest‐facing hillslopes in the Northern Hemisphere and between southeast‐ and northwest‐facing hillslopes in the Southern Hemisphere. Copyright © 2017 John Wiley & Sons, Ltd.

Sedimentology and Paleontology of the Upper Cretaceous Wahweap Formation sag ponds adjacent to syndepositional normal faults, Grand Staircase-Escalante National Monument, Utah

During the development of the East Kaibab monocline, listric normal faulting related to outer arc influenced the sedimentation style of the Upper Cretaceous Wahweap Formation. The initiation of the Laramide Orogeny was therefore recorded in the sedimentary record of south-central Utah. Evidence for this includes the preservation of sag ponds adjacent to two of the normal faults in our study area, which developed when fault movement created topographic features. Ancient sag-pond deposits are likely under-identified in the rock record. This study demonstrates their significance and potential for unraveling fault histories.The northern, younger, sag-pond deposit is located at the boundary between the upper and capping sandstone members of the Wahweap Formation, and consists of sandstone dikes and sills hosted in gray mudstones and siltstones with no discernable invertebrate fauna, but some small macerated flora. The second southern sag-pond fill, is located at the base of the upper member. The sag pond is older, larger in area, and contains a thicker deposit. In contrast to the northern sag-pond deposit siltstones and mudstones are gray and visiblity structureless. Within the southern sag pond there are a series of fossil horizons consisting mainly of juvenile unionid bivalves, a lesser number of gastropods, and macerated plants. Comparison of the two preserved Upper Cretaceous sag-pond deposits suggests two distinct responses to fault movement, perhaps governed by fault kinematics, manifested in sedimentation style and type; the impact of faunal invertebrate invasion; and post-sedimentation deformation.

A kinematic trishear model to predict deformation bands in a fault-propagation fold, East Kaibab monocline, Utah

Well core with numerous deformation bands in the reservoir interval may or may not be indicative of reduced effective reservoir permeability at the scale of well drainage areas. Many dense concentrations of deformation bands are related to the damage zone of a larger fault. However, some populations are more broadly distributed. We analyze one such population associated with the East Kaibab monocline in southern Utah. A kinematic trishear analysis is compared with field-based strain measurements. We find that the widespread dense deformation-band populations correspond to a broad zone of relatively high strain across the structure. Fault-damage zone models are inadequate to explain these occurrences. Our results show that, where deformation bands are known to occur from core in a folded reservoir, finite strains can be used to estimate their lateral and volumetric extents. However, we also find that the orientations of deformation bands predicted by our modeling are highly sensitive to the strain path. This indicates that path-independent methods for estimating strain such as curvature analysis are not fully appropriate for application to deformation bands. Ultimately, any such method requires information relating rock properties with propensity to form deformation bands to be predictive.

Relationship of compaction bands in Utah to Laramide fault-related folding

Multiple sets of compaction bands of southwestern Utah occur in Navajo Sandstone near a bend in the adjacent East Kaibab monocline. Forward mechanical models of blind-thrust fault deformation are used in this paper to investigate the spatial relationship between compaction bands and fault-related folding. Results are consistent with the East Kaibab monocline being underlain by a west-dipping blind high-angle reverse fault between ~ 1.5 and 5 km depth below the top of the Navajo Sandstone. Reverse slip along this reactivated fault during the Laramide orogeny is inferred to have produced values of compactional normal strain that were largest in the footwall near the concave map-view bend in the monocline. The calculated compactional normal strains and Coulomb stress increases are consistent with the field occurrence of pure and shear-enhanced compaction bands in this area. Bends, relays, stepovers, or other geometric complexities above blind reverse faults are thus inferred to be potential sites for compaction band localization in appropriate rock types.

Porosity and grain size controls on compaction band formation in Jurassic Navajo Sandstone

Determining the rock properties that permit or impede the growth of compaction bands in sedimentary sequences is a critical problem of importance to studies of strain localization and characterization of subsurface geologic reservoirs. We determine the porosity and average grain size of a sequence of stratigraphic layers of Navajo Sandstone that are then used in a critical state model to infer plastic yield envelopes for the layers. Pure compaction bands are formed in layers having the largest average grain sizes (0.42–0.45 mm) and porosities (28%), and correspondingly the smallest values of critical pressure (∼22 MPa) in the sequence. The results suggest that compaction bands formed in these layers after burial to ∼1.5 km depth in association with thrust faulting beneath the nearby East Kaibab monocline, and that hardening of the yield caps accompanied compactional deformation of the layers.

Growth faults in the Kaiparowits Basin, Utah, pinpoint initial Laramide deformation in the western Colorado Plateau

Growth faults and synorogenic sedimentary strata preserved in Upper Cretaceous units on the margin of the Kaiparowits Basin in southern Utah pinpoint the timing of onset of the Laramide orogeny in this region between 80 and 76 Ma. The newly identified listric normal faults, exposed in the steep limb of the East Kaibab monocline, sole into shales and evaporites of the Jurassic Carmel Formation. Faults lose displacement up-section through the Cretaceous Wahweap Formation and are associated with numerous coseismic sedimentary features. Fault orientations and slip vectors yield strain directions consistent with fold-related extension parallel to the axis of the growing East Kaibab monocline, or with development of a pull-apart basin at a bend in the trend of the fold. The association of the faults with the steep limb of a major basement-cored structure links them to initial Laramide movement along the Kaibab Uplift. When combined with recent radiometric ages of rock units bracketing the fault-induced growth strata, these sedimentary and structural features narrowly define the onset of Laramide deformation in the western Colorado Plateau.

Pseudo 3-D modeling of trishear fault-propagation folding

Basement structures, to which trishear fault-propagation models have most successfully been applied, are commonly three-dimensional folds formed at the tip-line of a fault. We present here a ‘pseudo-3D’ trishear model in which various parameters are permitted to vary along strike and oblique-slip can be modeled. These variations may be combined in an infinite number of ways, facilitating the simulation of many real structures. A thrust changing from blind to emergent can be produced by a change in the slip or propagation-to-slip (P/S) along strike. Folds with forelimbs changing from overturned to upright along strike can be modeled either by changing the slip, P/S or trishear angle. Also some minor folds perpendicular or oblique to the main structure can result from changes in the trishear angle or fault angle along the strike. Models including growth strata show that it is practically impossible to distinguish between growth and pre-growth strata using the map patterns. As a field test, we have modeled the oblique slip East Kaibab monocline, demonstrating a good fit between the field observations and model predictions.

Conjugate Riedel deformation band shear zones

Our investigations have disclosed that individual Riedel shear zones may organize themselves into broadly distributed though rigorously oriented intraformational conjugate systems which may form without relationship to, or dependence upon, an underlying basement fault zone. The Riedel shear zones we mapped are zones of deformation bands, which developed as the preferred deformation mechanism in porous Navajo Sandstone (Jurassic). In the Cottonwood area, located at the northern end of the Kaibab Uplift, a conjugate normal Riedel deformation band shear system developed during the Laramide in the uppermost Navajo Sandstone on the outer arc of the upper hinge zone of the East Kaibab monocline. In the Sheets Gulch area, located at the northern end of the Waterpocket Fold, a conjugate strike-slip Riedel deformation band shear system developed during the Laramide in upper Navajo Sandstone within an imperfect transfer zone between the northeast-vergent Circle Cliffs Uplift and the southwest-vergent Miners Mountain Uplift. Within both the Cottonwood and Sheets Gulch areas there are tens to hundreds of Riedel shear zones, the largest of which are up to hundreds of meters in trace length. In classic Riedel fashion, the synthetic R-shears within each Riedel shear zone depart by ∼15° from the zone as a whole and are arranged in an en échelon, overstepping geometry. The antithetic R′-shears depart by ∼75° from the Riedel shear zones of which they are a part, and are especially abundant in transfer zones where they create hard linkages between overstepping R-shears. At both localities the Riedel shear zones occur in two sets that intersect at ∼60°. The Riedel shear geometry is self-similar from the scale of hand samples (and thin sections) where offsets are measured in centimeters (or millimeters), to the map scale where displacements are measured in meters. Because of the small amount of deformation which had to be accommodated in each of the two study areas, and the limits imposed by the strain-hardening nature of deformation banding, we may be seeing a rare snapshot that records an image of early, arrested fault-system development in relatively homogeneous, porous sandstone. The literature on classic Riedel shear zones postulates that displacement and shear along Riedel shears brings about a localized reorientation of stress. This interpretation can be tested and confirmed, using the geometry and kinematics of conjugate Riedel systems. Detailed understanding of the total nested geometric characteristics of the conjugate Riedel deformation band shear zone systems also provides insight regarding controls on reservoir-scale fluid flow. The low permeability of the deformation band shear zones tends to compartmentalize the Navajo Sandstone into chambers along which fluid flow is channeled. The geometry and spacing of the deformation band patterns controls shapes and sizes of the compartments, which in these examples tend to be long, polyhedral, porous chambers marked by either diamond- or rhombic-shaped cross-sections.

Monocline development by oblique-slip fault-propagation folding: the East Kaibab monocline, Colorado Plateau, Utah

Fault relationships along a 50-km stretch of the East Kaibab monocline in southern Utah suggest that Late Cretaceous/early Tertiary development of the structure involved a significant component of right-lateral strike-slip displacement, accommodated by basement-rooted faulting and fault-propagation folding. Evidence of oblique slip is provided mainly by pervasive map-scale and outcrop-scale faults that define a shear zone occupying the steep east-dipping limb of the monocline for at least its northernmost 50 km. Dominant fault orientations are synthetic and antithetic to the shear zone, and accommodate reverse-right-lateral and reverse-left-lateral slip, respectively. Structural style within the shear zone changes character and increases in intensity with progressively lower structural and stratigraphic levels in the fold, suggesting that the shear zone propagated upward from a basement-rooted fault during monocline formation. We conclude that horizontal, ENE-directed, Laramide compression drove reverse-right-lateral slip on the basement fault zone beneath the developing East Kaibab monocline. The resulting transpressional fault-propagation fold is marked in southern Utah by 1600 m of reverse displacement and possibly 8000 m of right-lateral displacement across the shear zone and associated monoclinal flexure.

Interlayer slip and joint localization in the East Kaibab Monocline, Utah: field evidence and results from numerical modelling

Abstract The mechanics of deformation in multilayer flexures is analysed by comparing field observations of joint clusters from the East Kaibab Monocline, Utah with fracture patterns produced in analytical and numerical experiments. Dune boundaries (bedding planes) were mapped through the thickness of the aeolian Navajo Formation, and the occurrence of joints related to dune boundary slip and fold curvature was documented. Slip along dune boundaries, as evidenced by joint clusters oblique to bedding, occurs along the steep limb of the fold and in the middle of the Navajo. Joints perpendicular to bedding and parallel to the fold axis occur near the synclinal hinge. Numerical experiments examine a layer flexed to match the Navajo at Hackberry Canyon with both uniform and observed distribution of dune boundaries. Within the numerical experiments, horizontal frictional interfaces slip within the centre of the layers where dips are steepest, and opening-mode fractures related to curvature form within the anticlinal and synclinal hinges of the fold. Thus, the first-order numerical results match field observations. This study illustrates the important roles of mechanical stratigraphy and interlayer slip in multilayered folding and the contribution of bedding-plane faults and fold curvature in the production of joint clusters.

Predicting fracture localization in folded strata from mechanical stratigraphy and fold shape: Case study of east Kaibab Monocline, Utah

Joints within folds are often localized within zones. These joint clusters may influence the flow of fluids in the subsurface but are often undetectable on conventional seismic lines. Joints develop in folded strata in response to fold shape and mechanical stratigraphy. Mechanical stratigraphy describes the distribution of layers (layer thicknesses) and the nature of the layer contacts. Within folded strata, joints may localize at regions of high curvature within the outer arc of the fold or at regions of interlayer slip along fold limbs. This study compares the observed fracture pattern within the Navajo Formation at East Kaibab Monocline, Utah with those predicted by numerical models in order to validate the modeling technique. The Boundary Element Method model simulates folding of the Navajo Formation; fold shape and mechanical stratigraphy are estimated from field observations. The numerical model matches the observed fracture pattern while the details of fracture localization will be controlled by heterogeneous interlayer material. The technique presented in this study may be used to predict the location and extent of subsurface joint clusters if fold shape can be resolved from seismic lines and mechanical stratigraphy (layer thickness and contact friction) determined from borehole data.

Influence of cementation and permeability on wave velocities in poorly consolidated sands

Joints within folds are often localized within zones. These joint clusters may influence the flow of fluids in the subsurface but are often undetectable on conventional seismic lines. Joints develop in folded strata in response to fold shape and mechanical stratigraphy. Mechanical stratigraphy describes the distribution of layers (layer thicknesses) and the nature of the layer contacts. Within folded strata, joints may localize at regions of high curvature within the outer arc of the fold or at regions of interlayer slip along fold limbs. This study compares the observed fracture pattern within the Navajo Formation at East Kaibab Monocline, Utah with those predicted by numerical models in order to validate the modeling technique. The Boundary Element Method model simulates folding of the Navajo Formation; fold shape and mechanical stratigraphy are estimated from field observations. The numerical model matches the observed fracture pattern while the details of fracture localization will be controlled by heterogeneous interlayer material. The technique presented in this study may be used to predict the location and extent of subsurface joint clusters if fold shape can be resolved from seismic lines and mechanical stratigraphy (layer thickness and contact friction) determined from borehole data.

Predicting fracture localization in folded strata from mechanical stratigraphy and fold shape: Case study of East Kaibab Monocline, Utah

Long term stability of waste emplacement drifts is of interest in assessing the safety of disposal of high-level nuclear waste (HLW) in the proposed repository at Yucca Mountain (YM). The repository preclosure operation period is about 100 years, and the decision regarding the use of backfill in the emplacement drifts during the postclosure period of about 10,000 years has not been finalized. Two significant factors that can induce drift instability include thermal loads generated by the decay of emplaced waste and repeated seismic loads from earthquakes. One of the failure mechanisms for an excavation in a jointed rock mass subjected to repeated seismic loading is through accumulation of shear displacements along joints. These dynamic ground motions at YM due to earthquakes (and possible nearby weapons testing) will take place in the presence of in situ stresses, excavation induced stresses, and thermal-mechanically induced stresses. This paper presents a discrete element analysis using the code UDEC (Version 3.0) to investigate the effect of repeated seismic loading on cumulative joint slip and failure around a heated, unsupported, emplacement drift in the proposed repository at YM. A 100 MTU/acre thermal loading was used. Computer results indicate that slip along joints and closing of the drift take place with both single and repeated episodes of seismic loading at peak accelerations of 0.4g if yielding has occurred in the rock around the drift during the thermal-mechanical loading stage prior to seismic loading. This cumulative effect of repeated seismic loading confirms the findings of a field investigation (Hsiung et al. 1992) and a laboratory study (Hsiung et al. 1997). However, if the rock remains in the elastic state after the thermal loading is applied, no measurable cumulative slip on joints or drift convergence is evident with repeated episodes of seismic loading up to 0.4g, aside from that which occurs during the first sequence of seismic loading.

Stratigraphy and Depositional History of Thousand Pockets Tongue of Page Sandstone and Crystal Creek Member of Carmel Formation (Middle Jurassic), Southwestern Utah: ABSTRACT

Between the East Kaibab monocline and Zion National Park in southwestern Utah, gray, cliff-forming, cross-bedded quartz sandstone of the Thousand Pockets Tongue of the Page Sandstone grades northwestward into red, slope-forming, flat-bedded quartz sandstone of the Crystal Creek Member of the Carmel Formation. On the basis of stratigraphic position, both members are considered Bathonian in age. Coastal deposits of the Thousand Pockets Tongue prograded northwestward and interfingered with contemporaneous submarine deposits of the Crystal Creek Member along a northeast-southwest trending shoreline of the Middle Jurassic seaway. The Thousand Pockets Tongue is divided into three parts characterized by distinct sedimentary features and paleoenvironments. The gray lower part contains cross-bedded eolian sandstones (cross-bedded sandstone facies) which grade into evenly laminated and cross-bedded beach sandstones (Round Valley Draw facies). The red middle part is characterized by flat laminations, echinodern fragments, and a distribution which suggest a lagoon/tidal-flat environment. In the gray upper part, cross-bedded sandstones of eolian origin (Paria Canyon facies) grade into evenly laminated and cross-bedded beach sandstones (yellow sandstone ledge facies) and locally enclose red, flat-bedded units deposited in a washover channel-wind-tidal flat complex (red lenticular sandstone facies). The Crystal Creek Me ber is typified by evenly laminated, massive, and cross-bedded units and a lateral facies relation which suggest a lower beach and subtidal environment where storm and tidal currents dominated. Cross-stratification measurements from eolian facies in lower and upper Thousand Pockets Tongue indicate north-northeasterly winds during Bathonian time. The marginal-marine and submarine interpretation of the red beds in the Thousand Pockets Tongue and Crystal Creek Member, respectively, lends support to a diagenetic origin for the red color of these beds. End_of_Article - Last_Page 556------------

Pediments and Pediment-Forming Processes near House Rock, Arizona

At the base of the East Kaibab monocline, 6 miles south of House Rock, Arizona, stand two levels of pediment remnants, cut largely in Moenkopi red shales and capped by boulders and gravels of Kaibab limestone. The pediments are produced primarily by lateral corrasion by master-streams, aided by rill-wash and gully erosion. Pediment-cutting has been interrupted by periods of aggradation in which thick protective gravels were spread upon the pediments.

GEOLOGY AND GEOGRAPHY OF CENTRAL KANE COUNTY, UTAH

This paper, based on surveys made chiefly in 1943 and 1944, describes the geography and geology of central Kane County, Utah, an area of about 570 square miles. The region is semiarid, utilized almost entirely as forage ground for sheep and cattle. The oldest rocks exposed are the Hermit shale and the Kaibab limestone of Permian age. Above these lie the Triassic, Jurassic, and Cretaceous formations characteristic of the Colorado plateaus. Igneous and metamorphic rocks are absent. The regional north and northeast dips of the sedimentary beds have been interrupted by the broad Kaibab upwarp, the strongly accentuated East Kaibab monocline, and the Paunsaugunt fault, which have disturbed all the formations exposed. The physiographic history of the region records two long cycles of regional denudation and shorter periods of alternating aggradation and degradation. Conspicuous topographic features are the White Cliffs and their outlying mesas and peaks, the Vermilion Cliffs, the Shinarump Cliffs, the Kaibab Plateau, the Coxcomb, House Rock Valley, and two broad surfaces of erosion—Wygaret Terrace and Kimball Valley.

GEOMORPHOLOGY AND STRUCTURE OF THE EAST KAIBAB MONOCLINE, ARIZONA AND UTAH

Research Article| February 01, 1945 GEOMORPHOLOGY AND STRUCTURE OF THE EAST KAIBAB MONOCLINE, ARIZONA AND UTAH DONALD L BABENROTH; DONALD L BABENROTH COLUMBIA UNIVERSITY, NEW YORK, N. Y. Search for other works by this author on: GSW Google Scholar ARTHUR N STRAHLER ARTHUR N STRAHLER * Deceased. COLUMBIA UNIVERSITY, NEW YORK, N. Y. Search for other works by this author on: GSW Google Scholar GSA Bulletin (1945) 56 (2): 107–150. https://doi.org/10.1130/0016-7606(1945)56[107:GASOTE]2.0.CO;2 Article history received: 30 Mar 1944 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation DONALD L BABENROTH, ARTHUR N STRAHLER; GEOMORPHOLOGY AND STRUCTURE OF THE EAST KAIBAB MONOCLINE, ARIZONA AND UTAH. GSA Bulletin 1945;; 56 (2): 107–150. doi: https://doi.org/10.1130/0016-7606(1945)56[107:GASOTE]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The East Kaibab monocline, a compound flexure downthrown 2000 to 5000 feet on the east side, extends from the San Francisco Peaks volcanic field, Arizona, north 150 miles to Bryce Canyon, Utah. South of the Grand Canyon the monocline has several branches which make abrupt changes of strike. The main flexure west of Cameron trends east, while other segments strike northwest, north, and northeast. With many small grabens, single faults, and rows of cinder cones the flexures form a structural pattern of three intersecting trends.The main monocline, paralleled by the Butte fault, runs north across the eastern end of the Grand Canyon. A minor branch, paralleled by the Cremation fault, runs northwest into the Grand Canyon from Grandview Point. The Colorado River follows the strike of these major structures and may have had a subsequent origin in a belt of weak Triassic strata swinging south around the plunging Kaibab arch. The Little Colorado may have developed later in a similar belt at the foot of the East Kaibab monocline.North of the Grand Canyon the monocline forms the eastern Kaibab Plateau margin and for part of this distance is a double or triple flexure. In Utah the monocline is a single great fold in Jurassic and Cretaceous strata. At Canaan Peak the Eocene Wasatch formation unconformably overlies beveled Upper Cretaceous strata in the monocline, indicating Laramide flexing. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.