Structural geologic evolution of the Colorado Plateau

Davis, George H.; Bump, Alex

doi:10.1130/2009.1204(05)

Cited by 26 publications

(20 citation statements)

References 121 publications

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“…Several thousand meters of Jurassic and Cretaceous strata would have buried the Moenkopi formation until the uplift of the Colorado Plateau ~30–35 Ma [ Dumitru et al ., ; Sprinkel , ; Mathis , ; Pederson et al ., ; Davis and Bump , ; Moucha et al ., ; Lavendar et al ., ; Karlstrom et al ., ]. Gypsum veins must have formed since ~8 Ma because gypsum is stable at <60°C (above 2 km), and the Moenkopi formation is modeled to have been exhumed to less than 2 km depth in the past 8 Ma (Figure ).…”

Section: Discussionmentioning

confidence: 99%

“…Journal of Geophysical Research: Planets [Dumitru et al, 1994;Sprinkel, 1994;Mathis, 2000;Pederson et al, 2002;Davis and Bump, 2009;Moucha et al, 2009;Lavendar et al, 2011;Karlstrom et al, 2012]. Gypsum veins must have formed since~8 Ma because gypsum is stable at <60°C (above 2 km), and the Moenkopi formation is modeled to have been exhumed to less than 2 km depth in the past 8 Ma (Figure 11).…”

Section: Earth Moenkopi Formationmentioning

confidence: 99%

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Gypsum veins in Triassic Moenkopi mudrocks of southern Utah: Analogs to calcium sulfate veins on Mars

Young

Chan

2017

JGR Planets

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Well‐exposed gypsum veins in the Triassic Moenkopi formation in southern Utah, USA, are similar to veins at Endeavour and Gale Craters on Mars. Both Moenkopi and Mars veins are hydrated calcium sulfate, have fibrous textures, and crosscut other diagenetic features. Moenkopi veins are stratigraphically localized with strontium and sulfur isotope ratios similar to primary Moenkopi sulfate beds and are thus interpreted to be sourced from within the unit. Endeavour veins seem to be distributed by lithology and may have a local source. Gale veins cut across multiple lithologies and appear to be sourced from another stratigraphic interval. Evaluation of vein network geometries indicates that horizontal Moenkopi veins are longer and thicker than vertical veins. Moenkopi veins are also generally oriented with the modern stress field, so are interpreted to have formed in the latest stages of exhumation. Endeavour veins appear to be generally vertical and oriented parallel to the margins of Cape York and are interpreted to have formed in response to topographic collapse of the crater rim. Gale horizontal veins appear to be slightly more continuous than vertical veins and may have formed during exhumation. Abrupt changes in orientation, complex crosscutting relationships, and fibrous (antitaxial) texture in Moenkopi and Mars veins suggest emplacement via hydraulic fracture at low temperatures. Moenkopi and Mars veins are interpreted as late‐stage diagenetic features that have experienced little alteration since emplacement. Moenkopi veins are useful terrestrial analogs for Mars veins because vein geometry, texture, and chemistry record information about crustal deformation and vein emplacement.

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Section: Discussionmentioning

confidence: 99%

Section: Earth Moenkopi Formationmentioning

confidence: 99%

Gypsum veins in Triassic Moenkopi mudrocks of southern Utah: Analogs to calcium sulfate veins on Mars

Young

Chan

2017

JGR Planets

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“…Uplifts in northern Sonora have not been characterized in terms of structural style; however, Laramide‐age tectonism is evident here by the presence of Upper Cretaceous sedimentary basins (Jacques‐Ayala et al, ). Within the Colorado Plateau to the north, Proterozoic shear zones were reactivated to form moderately‐dipping reverse faults and related monoclines of variable strike direction (Davis & Bump, ). The structural geology west of southeastern Arizona is considerably more complex due to high degrees of regional metamorphism.…”

Section: Discussionmentioning

confidence: 99%

“…Within the North American Cordillera, the average trend of Laramide structures is north‐northwest, although the trend of individual faults and uplifts ranges from east‐west to north‐south. This misalignment of structural trends with the regional compression direction is commonly attributed to reactivation of preexisting weaknesses in basement rock (e.g., Davis & Bump, ; Stone, ). Kinematic indicators such as slickenlines and shear zones indicate oblique slip along these misaligned structures in the direction of regional contraction (e.g., Johnston & Yin, ; Neely & Erslev, ; Tindall & Davis, ).…”

Section: Discussionmentioning

confidence: 99%

Discovery of Major Basement‐Cored Uplifts in the Northern Galiuro Mountains, Southeastern Arizona: Implications for Regional Laramide Deformation Style and Structural Evolution

Favorito

Seedorff

2018

Tectonics

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The Laramide orogeny is poorly understood in southeastern Arizona, largely because of complex structural overprinting by mid-Cenozoic extension that occurred over large areas. This study integrates new geological mapping with previous work, combined with structural reconstructions and forward modeling, to determine the primary structural style, timing, evolution, and kinematics of Laramide shortening in the northern Galiuro Mountains. Cenozoic normal faulting in the study area is minor and has only resulted in up to 13°of eastward tilting, as indicated by the gentle dips of synextensional strata. Detailed mapping has revealed newly identified reverse fault systems measuring at least 50 km in combined strike length. Each major fault strikes north-northwest, dips moderately to the west, places older rocks on younger, and has related fault-propagation folds. Once restored to their original orientation, reverse faults range in dip from 38°to 47°. These moderate dips of faults combined with related folds, the significant degree of basement involvement, and cover sequence lacking obvious penetrative deformation indicate that these faults are thick-skinned, basement-cored uplifts. Forward modeling and Cenozoic erosion surfaces suggest regionally extensive Laramide-age tilting to the west-southwest and gentle folding, possibly caused by a regional-scale reverse fault underlying the study area. These results are consistent with the interpretation that Laramide shortening in southeastern Arizona was primarily characterized by thick-skinned tectonics. Kinematic indicators, folded basement rocks, north-northwest strikes of reverse faults, and lack of evidence for basin inversion suggest that preexisting basement faults and fabrics had little or no effect on the subsequent structural evolution.Plain Language Summary The Late Cretaceous to early Eocene Laramide orogeny was a period of crustal shortening in the North American Cordillera that involved two different styles of reverse faulting. One style involves low-angle thrusts that typically slip parallel to bedding planes in layered rocks, whereas the other style involves faults that cut across bedding at moderate angles and continue downward through underlying crystalline basement rock. In southeastern Arizona, the style of Laramide shortening is debated and not well understood, in part because most of the region has undergone subsequent Cenozoic extension that has significantly rotated, dismembered, and buried most faults formed during Laramide crustal shortening. This study examines a newly discovered set of Laramide reverse faults that extend for more than 50 km along strike and that have only been affected by minor extension. Results from field mapping and structural modeling indicate that these faults are basement-involved, moderate-angle reverse faults. Because the upper crustal architecture across the region is largely consistent, the region as a whole may be characterized by moderate-angle reverse faults. Thus, nearby Laramide faults that have been previously interpr...

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“…Tectonic activity then resumed during the Laramide orogeny . Across the Colorado Plateau Laramide deformation is limited to a series of monoclines that include the Uncompahgre Plateau (Kelly, 1955;Williams, 1964;Bump and Davis, 2003;Davis and Bump, 2009), which exhibits as much as ~1000 m of structural relief. Moreover, the Colorado Plateau has undergone epeirogenic uplift resulting in a modern average elevation of ~2.2 km (McQuarrie and Chase, 2000;Pederson et al, 2002).…”

Section: Colorado and Uncompahgre Plateausmentioning

confidence: 99%

Geology of Unaweep Canyon and its role in the drainage evolution of the northern Colorado Plateau

et al. 2015

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Unaweep Canyon (Colorado, USA) is a large, Precambrian-cored gorge that bisects the Uncompahgre Plateau of the northeastern Colorado Plateau, but has no through-fl owing axial stream; it is drained by two underfi t creeks (East and WestCreek) that head at a divide within the canyon. The history of the canyon and its role in drainage evolution of the Colorado River system remain controversial. New mapping of both bedrock and Quaternary units as well as analyses of Quaternary deposits in and near the canyon shed light on its late Cenozoic history, and call into question whether the canyon was incised by a Cenozoic river, or merely exhumed by one. Gravels near the western mouth of Unaweep Canyon (Gateway, Colorado) exhibit a distinctive intermediate volcanic provenance recording the presence of an ancestral Gunnison River; the youngest gravels are dated to 1.46 ± 0.33 Ma. Previously documented coring within the canyon reveals a thick (locally >330 m) fi ll that includes a lacustrine succession (~140 m thick), dated to 1.4-1.3 Ma, overlain by stacked paleosols and a thick (~160 m) conglomeratic unit emplaced between 1.3 Ma and the present, in addition to a basal unit of possible late Paleozoic age. Lake formation refl ects catastrophic mass wasting in western Unaweep Canyon that blocked the ancestral Gunnison River, causing partial backfi lling of the canyon, and forcing the river to seek a lower elevation exit eastward by breaching the Mesozoic rim at the northeast end of Cactus Park (Mesa County, Colorado). Ultimately, the ancestral Gunnison River joined the lower elevation Colorado River near Grand Junction by 1.3 Ma, incising the East Creek of Unaweep Canyon during the overspilling event. Thermochronological data from Precambrian basement within Unaweep Canyon and Permian strata at the western mouth of the canyon indicate onset of incision in latest Miocene time (ca. 6-5 Ma), at a timeaveraged rate of ~210-275 m/m.y. Onset of canyon occupation and rapid incision by the ancestral Gunnison River coincided with the timing of integration of the lower Colorado River system to the Gulf of California. The synchroneity of this incision across the Colorado Plateau supports the inference of an ultimate tectonic or epeirorogenic driver for this widespread incision and ultimate drainage integration.Several aspects of this data set support the previously published hypothesis that the ancestral Gunnison River exhumed a paleovalley. New mapping at the western mouth of the canyon documents a paleovalley fi lled with Permian strata that leads into the modern Precambrian-hosted gorge of Unaweep Canyon. In addition, the ancestral Gunnison River paralleled the Uncompahgre Plateau before making a 90° turn to bisect the structural axis in a manner that opposes both the northwestward plunge of the uplift and the northeastward dip of its northern fl ank. The rate of incision of Unaweep Canyon exceeds regional time-averaged incision rates, consistent with removal of sedimentary fi ll rather than incision of crystalline basement. This hyp...

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Structural geologic evolution of the Colorado Plateau

Cited by 26 publications

References 121 publications

Gypsum veins in Triassic Moenkopi mudrocks of southern Utah: Analogs to calcium sulfate veins on Mars

Gypsum veins in Triassic Moenkopi mudrocks of southern Utah: Analogs to calcium sulfate veins on Mars

Discovery of Major Basement‐Cored Uplifts in the Northern Galiuro Mountains, Southeastern Arizona: Implications for Regional Laramide Deformation Style and Structural Evolution

Geology of Unaweep Canyon and its role in the drainage evolution of the northern Colorado Plateau

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