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Generalized Geologic map of the Powder River Basin and surrounding areas. Orange = Precambrian rocks, Blue = Paleozoic rocks, Green = Mesozoic and Cenozoic rocks. The area of Figure 2 is indicated by as shaded gray box.
Source publication
This study uses detrital zircon U-Pb geochronology to investigate the provenance of the Jurassic Sundance Formation in the western Powder River Basin, Wyoming. Understanding the provenance of the Sundance Formation is critical as it was deposited during the transition from cratonic to synorogenic sedimentation derived from the Se-vier-Laramide fore...
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... zircon U-Pb geochronology was utilized for this study to provide a provenance reconstruction of the Jurassic Sundance Formation in the Powder River Basin, north-central Wyoming (Figure 1). The concept presented and argued here indicates that basal Sundance sands deposited during the transgression of the Sundance seas have a recycled cratonic provenance. ...
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... Powder River Basin is a structural and topographic basin that covers about 56,000 km 2 in north-central of Wyoming, the adjacent part of Montana, and western South Dakota (Whipkey et al., 1991; Figure 1). The basin is bordered by basement-cored uplifts on three sides: The Bighorn Mountains to the west, the Laramie Range and Hartville Uplift on the south, and the Black Hills on the east (Johnson, 1992). ...
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... ages were subdivided for each sample into Archean, Penokean/Trans-Hudson, Yavapai/ Mazatzal, Midcontinent Granite-Rhyolite, Grenville ages, Pan-African, Taconic, and Acadian. Figure 10 provides frequency plots for the ages of each of the samples, which were used to extrapolate the relative age abundance of the grains for graphical interpretation of provenance and peak ages. ...
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... upper Sundance has age peaks at 159, 170, 243, 440, 545, 1082, 1467, 1681, and 1985 Ma with a composite age spectrum from 157 to 2949 Ma. The youngest age peak occurs in the Mesozoic Era at 159 Ma and the weighted mean average of the ten youngest grains is 160 Ma, which is an estimate of the maximum depositional age of the Sundance here ( Figure 11). K-S analysis was used to statistically compare the degree of differences between samples taken stratigraphically above and below the Sundance samples (Table 3). ...
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... the zircon-derived ages were compared to surrounding strata and dated using the same techniques as May et al. (2013), the K-S analysis shows that the lower Sundance is statistically indistinguishable from the older Triassic Chugwater. Further, the upper Sundance is indistinguishable from the overlying strata, with the exception for the Cloverly Formation ( Figure 12). ...
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... zircon U-Pb geochronology anD Provenance of the SUnDance formation, weStern PowDer river baSin, wyoming Figure 10. Frequency plots of the upper and lower Sundance members. ...
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... zircons from the upper Sundance sample records a large percent of Mesozoic aged grains and are a statistical match to the Sundance samples reported by May et al (2013). The upper Sundance Formation detrital age spectrum reveals similar age peaks as the lower Sundance except for the plentiful Mesozoic aged grains, which may indicate a distinct western source or a mixed source area that includes some sediment from the west as well as the erstwhile easterly provenance (Figure 14). ...
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... Jurassic Sundance Formation in the Powder River Basin is a uniquely important unit as it provides evidence for a dramatic shift in provenance, being the first unit in the region to have depositional age zircons and offers a time constraint of the onset of Sevier-Laramide Orogeny. Figure 14. Paleogoegraphic reconstruction of upper Sundance deposition following the retreat of the Sundance sea. ...
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... zircon U-Pb geochronology was utilized for this study to provide a provenance reconstruction of the Jurassic Sundance Formation in the Powder River Basin, north-central Wyoming (Figure 1). The concept presented and argued here indicates that basal Sundance sands deposited during the transgression of the Sundance seas have a recycled cratonic provenance. ...
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... Powder River Basin is a structural and topographic basin that covers about 56,000 km 2 in north-central of Wyoming, the adjacent part of Montana, and western South Dakota (Whipkey et al., 1991; Figure 1). The basin is bordered by basement-cored uplifts on three sides: The Bighorn Mountains to the west, the Laramie Range and Hartville Uplift on the south, and the Black Hills on the east (Johnson, 1992). ...
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... ages were subdivided for each sample into Archean, Penokean/Trans-Hudson, Yavapai/ Mazatzal, Midcontinent Granite-Rhyolite, Grenville ages, Pan-African, Taconic, and Acadian. Figure 10 provides frequency plots for the ages of each of the samples, which were used to extrapolate the relative age abundance of the grains for graphical interpretation of provenance and peak ages. ...
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... upper Sundance has age peaks at 159, 170, 243, 440, 545, 1082, 1467, 1681, and 1985 Ma with a composite age spectrum from 157 to 2949 Ma. The youngest age peak occurs in the Mesozoic Era at 159 Ma and the weighted mean average of the ten youngest grains is 160 Ma, which is an estimate of the maximum depositional age of the Sundance here ( Figure 11). K-S analysis was used to statistically compare the degree of differences between samples taken stratigraphically above and below the Sundance samples (Table 3). ...
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... the zircon-derived ages were compared to surrounding strata and dated using the same techniques as May et al. (2013), the K-S analysis shows that the lower Sundance is statistically indistinguishable from the older Triassic Chugwater. Further, the upper Sundance is indistinguishable from the overlying strata, with the exception for the Cloverly Formation ( Figure 12). ...
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... zircon U-Pb geochronology anD Provenance of the SUnDance formation, weStern PowDer river baSin, wyoming Figure 10. Frequency plots of the upper and lower Sundance members. ...
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... zircons from the upper Sundance sample records a large percent of Mesozoic aged grains and are a statistical match to the Sundance samples reported by May et al (2013). The upper Sundance Formation detrital age spectrum reveals similar age peaks as the lower Sundance except for the plentiful Mesozoic aged grains, which may indicate a distinct western source or a mixed source area that includes some sediment from the west as well as the erstwhile easterly provenance (Figure 14). ...
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... Jurassic Sundance Formation in the Powder River Basin is a uniquely important unit as it provides evidence for a dramatic shift in provenance, being the first unit in the region to have depositional age zircons and offers a time constraint of the onset of Sevier-Laramide Orogeny. Figure 14. Paleogoegraphic reconstruction of upper Sundance deposition following the retreat of the Sundance sea. ...
Citations
... (9) Sinuous channel belt with crevasse splay, local/regional avulsion and point bars. (10) Fanglomerates on the alluvial fan (Kraus, 1983(Kraus, , 1984Malone et al., 2017;Syzdek et al., 2019), indicating a near-source system. (11) Poorly drained floodplain, swampy and/or lacustrine environments in front of the Bighorn Mountains indicated by organic-rich beds and gley palaeosols (Wing & Bown, 1985;Davies-Vollum & Wing, 1998;Davies-Vollum, 1999, 2001 perennial discharge conditions favour FA4 sinuous-like channel development (cf. ...
The lower Eocene Willwood Formation of the Bighorn Basin, Wyoming, USA, is an alluvial succession with a sand content varying around 25%. It has been studied intensively for palaeontology, palaeoenvironments and palaeoclimates, as well as sedimentological and stratigraphic analysis. Channel dynamics were studied at a relatively low resolution throughout the basin over the geological time from late Palaeocene to early Eocene. Here, a high‐resolution study is reported to complement previous research at the basin scale. Efforts are made to document the characteristics and river planform styles of most sandstone bodies encountered through ca 300 m of alluvial stratigraphy in a 10 km2 area of the Deer Creek part of the McCullough Peaks area situated in the basin axis of northern Bighorn Basin. Four channel facies associations are recognized and ascribed to four river planform styles: crevasse channel, trunk channel, braided‐like channel and sinuous‐like channel, with the latter two types dominant. Braided‐like and sinuous‐like channel sandstone bodies differ significantly in thicknesses, being on average 6.1 m versus 9.0 m, but they have similar palaeoflow–perpendicular widths of on average 231 m and palaeoflow directions of on average N 003°. Braided‐like and sinuous‐like river planform styles show no spatial dependency in the 10 km2 study area. Results of this study are in line with existing basin‐scale depositional models that are composed of a single axial system fed by several transverse systems dominantly from the west. The feeding of these systems could be influenced by palaeoclimate changes possibly controlling their contribution over time, thereby impacting river planform styles. At the same time, changing water discharge hydrograph, sediment load, and overbank cohesiveness may have equally driven the observed river planform style changes within the basin without a major role of catchments.
... The oldest units of interest are the Stump Formation in western Wyoming and the Sundance Formation that crops out in the Bighorn Basin and South Dakota. These Upper Jurassic formations predate the Sevier orogeny and represent deposition within a shallow-marine setting prior to ca. 155 Ma (Fig. 2), though some suggest the uppermost Sundance Formation is related to the orogeny (Syzdek et al., 2019). The Stump Formation varies in thickness 30-120 m and is composed of a diverse lithologic suite of rippled and cross-bedded sandstone, limestone, and various mudrocks that contain marine bivalves, crinoids, and other invertebrates (Pipiringos and Imlay, 1979). ...
... These dates are consistent with MDA estimates from U-Pb radiometric dates from detrital zircons in the Bighorn Basin, which yielded 157.4 ± 1.9 Ma (three grains, mean square of weighted deviates [MSWD] = 1.0; May et al., 2013a) as well as an age peak at ca. 159 Ma in the upper Sundance Formation in the Powder River Basin (Syzdek et al., 2019). ...
... Moreover, these studies mostly targeted strata of the proximal foredeep and backbulge depozones of the foreland basin system. This leaves strata within Wyoming comparatively understudied (DeCelles and Burden, 1992;May et al., 2013aMay et al., , 2013bSyzdek et al., 2019), though they occupy an important medial position both in terms of the broader North American paleogeography and within the foreland basin system transect. The new data presented in this study, primarily from the forebulge depozone, represent an ~25% increase from existing records in the Wyoming foreland basin. ...
This Special Paper focuses on the evolution of the crust of the hinterland of the orogen during the orogenic cycle, and describes the evolution of the crust and basins at metamorphic core complexes. The volume includes a regional study of the Sevier-Laramide orogens in the Wyoming province, a regional seismic study, strain analysis of Sevier and Laramide deformation, and detrital zircon provenance from the Pacific Coast to the foreland between the Jurassic and the Eocene.
... Regional and local detrital zircon data sets are available for Paleozoic and Mesozoic strata in eastern Idaho and western Wyoming (May et al., 2013;Gehrels and Pecha, 2014;Link et al., 2014;Malone et al., 2017dMcGuire et al., 2019;Syzdek et al., 2019;Schwartz et al., 2019;Ronemus et al., 2021; http:// www.geochron.org). Cambrian rocks throughout the region lack Grenvillian-age grains, and all zircons are 1.7 Ga or older (May et al., 2013;Yonkee et al., 2014;Malone et al., 2017d), which indicate derivation from local basement rocks. ...
... The Stump, Preuss, and Nugget Formations likely contributed sediment and zircons to the synorogenic conglomerates. Lower Jurassic strata maintain the prominence of Grenville and Paleozoic zircons that originated from the Appalachian highlands (Dickinson and Gehrels, 2009), whereas Middle Jurassic strata record the first appearance of zircons from the magmatic arc to the west (May et al., 2013;Gentry et al., 2018;Syzdek et al., 2019). ...
... The Stump Formation may represent the earliest evidence of Sevier tectonism, although the restored (pre-thrust) location of the Gibbs Creek exposure is ~200 km east of the Sevier arc (Burchfiel et al., 1992) and is overlain by the Lower Cretaceous Ephraim Conglomerate shed off the Paris thrust sheet. The Stump Formation is stratigraphically equivalent to the Sundance Formation to the east (May et al., 2013;Syzdek et al., 2019). ...
The results of new detrital zircon analyses of 15 (n = 1334) Sevier belt synorogenic (Jurassic-Eocene) conglomerates combined with U-Pb zircon ages from the literature (n = 2638) support the structurally dynamic role of the western Paris thrust sheet as the dominant high-standing, out-of-sequence portion of the Sevier belt. This result requires modification of the traditional structural view of the thinskinned Sevier fold-and-thrust belt having formed by west-to-east shortening over an ~100 m.y. period (ca. 150-50 Ma) with episodic thrust motions that become younger toward the craton (east), as constrained by numerous synorogenic deposits shed to the east from each thrust hanging wall. Sevier thrusting was preceded by deposition of the Jurassic Stump Formation, which has a maximum depositional age of 149 Ma and a unique detrital zircon and heavy mineral (garnet, magnetite) provenance. The oldest thrust, the Paris (Willard) thrust, eroded and deposited the Jurassic-Cretaceous Ephraim Conglomerate as a synorogenic fan devoid of quartzite clasts and with a detrital zir-con provenance consistent with reworked sediment from the fold belt, but not from the hinterland or the Sierra Nevada arc of the orogenic system. All subsequent syn-orogenic deposits from the mid-Cretaceous Echo Conglomerate (Meade-Crawford thrust) to a variety of more easterly Eocene deposits (Sevier belt, Green River, Absa-roka, and Bighorn basins) are rich in quartzite clasts. All the quartzite clasts were eroded from the Paris thrust hanging wall, which reached its peak orogenic height at ca. 95 Ma, 50 m.y. after first motion, and the Proterozoic Brigham Group remained a quartzite clast source for ~40 m.y. The detrital zircon signatures of these samples require additional sources of sediment, reworked from the hinterland and the Sierra Nevada and Idaho Batholith arcs, thus implying that long-distance sediment fairway(s) were active during the Mesozoic-early Cenozoic. Based on the same detri-tal zircon data, variable sources of sediment are inferred between each of the thrust Malone, D.H., Craddock, J.P., and Konstantinou, A., 2022, Timing and structural evolution of the Sevier thrust belt, western Wyoming, in Craddock, J.P., Malone,
... Our study area is in the northeastern Bighorn Basin of Wyoming, (Bellahsen et al., 2006; Figure 1). The Middle Jurassic Sundance Formation rests conformably beneath the Morrison Formation (Syzdek et al., 2019); the Lower Cretaceous Cloverly Formation unconformably overlies the Morrison Formation (D'Emic et al., 2019). ...
... The Cambrian Flathead Sandstone reflects local derivation from the underlying Precambrian basement rocks (Malone, Craddock, & Kenderes, 2017), but from Carboniferous through Triassic time, sands originated in the Appalachian highlands several thousand kilometers to the east (Dickinson & Gehrels, 2009; Garber et al., 2018). The local sedimentary provenance evolved deposition of the Sundance and Morrison formations as new source areas emerged in the Sevier orogenic belt to the west and the volcanic arcs beyond(May et al., 2013;Syzdek et al., 2019). ...
Here we present the detrital zircon age spectra for five (n=36, 68, 66, 41, 29) red quartzite gastroliths collected from the top of the Late Jurassic Morrison Formation in the eastern Bighorn Basin, Wyoming, USA. The detrital zircon age spectra reveal geon 17 maximum depositional ages, and age peaks that are Yavapai (geon 17), Penokean (geon 18) and Archean (>geon 25). The color, texture, composition and zircon age spectra of these exoliths are indistinguishable from those of geon 16 (i.e. Baraboo interval) quartzites present in the Laurentian midcontinent more than 1000 km to the east. We interpret that these gastroliths were ingested by dinosaurs, most likely sauropods, in the Laurentian midcontinent and then transported in their digestive tracts to the site of deposition. These data support the hypothesis of long‐distance dinosaur migration, perhaps following low energy, continental‐scale drainage systems that flowed from the Appalachian highlands to the Morrison Formation depositional basin.
... A western source was hypothesized for the Middle Jurassic Sawtooth Formation of northern Montana based on a single Mesozoic zircon (Fuentes et al., 2009). However, the onset of arc-derived detritus reaching the foreland basin system was evidently delayed until at least the Callovian in the Powder River Basin of Wyoming (Fig. 1A), where sediment from the lower Callovian sandstone of the Jurassic Sundance Formation is devoid of Mesozoic grains while the upper sandstone contains them in abundance (Syzdek et al., 2019). Additionally, the MDA of the Swift Sandstone of the Ellis Group in the Bridger Range is 154.8 ± 0.58 Ma (Table 2), which supports a younger depositional age compared to the Ellis Group in northern Montana (Fuentes et al., 2011). ...
... Regionally, samples from northern Wyoming (May et al., 2013;Syzdek et al., 2019) show an increased abundance of grains derived from recycling of the U.S. passive margin while samples in northern Montana display a well-mixed source signature (Fig. 8A). This likely reflects northwest directed basin-axial sediment transport within the foreland basin system, likely via longshore drift within a marginal marine environment. ...
The Bridger Range of southwest Montana, USA, preserves one of the most temporally extensive sedimentary sections in North America, with strata ranging from Mesoproterozoic to Cretaceous in age. This study presents new detrital zircon geochronologic data from eight samples collected across this mountain range. Multidimensional scaling and non-negative matrix factorization statistical analyses are used to quantitatively unmix potential sediment sources from these and 54 samples compiled from previous studies on regional correlative strata. We interpret these sources based on reference data from preserved strata with detrital zircon signatures likely representative of ancient sediment sources. We link these sources to their sinks along sediment dispersal pathways interpreted using available paleogeographic constraints. Our results show that Mesoproterozoic strata in southwest Montana contain detritus derived from the nearby craton exposed along the southern margin of the fault-bounded Helena Embayment. Middle Cambrian strata were dominated by the recycling of local sources eroded during the development of the Great Unconformity. In Devonian−Pennsylvanian time, provenance in southwest Montana shifted to more distal sources along the northeastern to southeastern margins of Laurentia, but more western basins received detritus from outboard sources along a tectonically complicated margin. By the Late Jurassic, provenance in the developing retroarc foreland basin system was dominated by Cordilleran magmatic arcs and fold-thrust belt sources to the west. Eastward propagation of the fold-thrust belt caused recycling of Paleozoic and Jurassic detritus into the foreland basin to dominate by the Early Cretaceous.
The Powder River basin is among several yoked inter-montane basins that occur within the Laramide foreland. More than 2000 m of Paleogene synorogenic strata fill the basin, which consists of the Fort Union and Wasatch Formations. Pumpkin Buttes are in the southwestern area of the Powder River basin; ten to twenty meters of conglomeratic sandstone and mudstone of the post-Laramide Oligocene White River Formation caps the buttes. Our broad goal is to characterize the provenance of White River Group strata of the Rocky Mountains and Great Plains and the late Paleogene burial of this region. Here we present detrital zircon data (LA-ICPMS at the Arizona Laserchron Center) for the matrix of the basal conglomeratic sandstone at Pumpkin Buttes (z=104). The youngest zircon fraction is middle Eocene in age, indicating a maximum age of deposition of ~46 Ma. These zircons were likely sourced by the Absaroka volcanic field 250 km to the west. The principal age peak is ~1460 Ma, which was likely sourced from basement-cored Laramide uplifts in central Colorado more than 500 km to the southwest. The age spectrum also includes smaller Yavapai (geon 17) and Archean (geon 27 and >geon 30) age peaks. The Yavapai zircons were likely derived from central Colorado, whereas the Archean zircons were likely sourced from the Beartooth and Tobacco Root Mountains of southwest Montana more than 350 km to the northwest. Thus, the zircon age spectrum reveals a variety of distal sediment source areas, mainly from the tops prominent mountain ranges. Our data set supports the hypothesis that the Laramide ranges in this area were buried by the early Oligocene, with regional high topography supplying the bulk of the sediment to the Powder River basin at this time.
An enigmatic transition from the storm‐dominated, offshore to lower shoreface deposits of the Redwater Shale Member (Sundance Formation) to the overlying mixed tidal and aeolian Windy Hill Sandstone (Morrison Formation) in the Oxfordian of the North American Western Interior has long been a source of intrigue. Previously proposed drivers include the progradation of a large, tide‐dominated delta onto a storm‐dominated shelf, a complete reorganisation of the basin's hydrodynamics and climate, or the development of a regional unconformity (termed the J‐5). In south‐eastern Wyoming, the Redwater Shale is characterised as an offshore to distal shoreface deposit with glauconitic siltstones and sandstones punctuated by coquinoid and sandy tempestites and hosting a Cruziana Ichnofacies. The Windy Hill Sandstone, a time‐transgressive, sand‐rich, intertidal succession with classic Pteraichnus and stressed Skolithos Ichnofacies, sharply overlies the Redwater Shale and records an abrupt basinward shift in facies that accompanied at least tens of metres of sea‐level fall. New, detailed sedimentological, ichnological and architectural data collected across this transition in the study area provide fresh insights into the depositional history of these units and demonstrates the existence locally of a composite J‐5 unconformity. The unconformity developed as tectonically driven, prograding shoreline trajectories of the Redwater Shale gave way to degrading trajectories of the Windy Hill Sandstone, leading to a forced regression and formation of a regressive surface of marine erosion. The sharp juxtaposition of intertidal flat facies (Pteraichnus Ichnofacies) directly upon offshore to lower shoreface deposits (Cruziana Ichnofacies) is the key to recognising the unconformity and proves the value of the previously underutilised ichnological data.
