Relationship of Unconformities, Tectonics, and Sea Level Changes in the Cretaceous of the Western Interior, United States

Weimer, Robert J.

doi:10.1306/m41456c19

Cited by 17 publications

(8 citation statements)

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“…The Cretaceous Western Interior Basin has been commonly referred to as an epeiric seaway or a ramp setting. Maximum water depths in the central and eastern part of the basin were 100–300 m (Weimer, 1983; Sageman & Authur, 1994). Paleo‐bathymetry ranges for different upper Cretaceous units are listed in Table 2.…”

Section: Methodsmentioning

confidence: 99%

Linkage of Sevier thrusting episodes and Late Cretaceous foreland basin megasequences across southern Wyoming (USA)

et al. 2005

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Deposition and subsidence analysis, coupled with previous structural studies of the Sevier thrust belt, provide a means of reconstructing the detailed kinematic history of depositional response to episodic thrusting in the Cordilleran foreland basin of southern Wyoming, western interior USA.The Upper Cretaceous basin ¢ll is divided into ¢ve megasequences bounded by unconformities. The Sevier thrust belt in northern Utah and southwestern Wyoming deformed in an eastward progression of episodic thrusting.Three major episodes of displacement on the Willard-Meade, Crawford and 'early' Absaroka thrusts occurred from Aptian to early Campanian, and the thrust wedge gradually became supercritically tapered.The Frontier Formation conglomerate, Echo Canyon and Weber Canyon Conglomerates and Little Muddy Creek Conglomerate were deposited in response to these major thrusting events. Corresponding to these proximal conglomerates within the thrust belt, Megasequences 1, 2 and 3 were developed in the distal foreland of southern Wyoming.Twodimensional (2-D) subsidence analyses show that the basin was divided into foredeep, forebulge and backbulge depozones. Foredeep subsidence in Megasequences 1, 2 and 3, resulting from Willard-Meade, Crawford and 'early'Absaroka thrust loading, were con¢ned to a narrow zone in the western part of the basin. Subsidence in the broad region east of the forebulge was dominantly controlled by sediment loading and inferred dynamic subsidence. Individual subsidence curves are characterized by three stages from rapid to slow. Controlled by relationships between accommodation and sediment supply, the basin was ¢lled with retrogradational shales during periods of rapid subsidence, followed by progradational coarse clastic wedges during periods of slow subsidence. During middle Campanian time (ca. 78.5^73.4 Ma), the thrust wedge was stalled because of wedge-top erosion and became subcritical, and the foredeep zone eroded and rebounded because of isostasy.The eroded sediments were transported far from the thrust belt, and constitute Megasequence 4 that was mostly composed of £uvial and coastal plain depositional systems. Subsidence rates were very slow, because of post-thrusting rebound, and the resulting 2-D subsidence was lenticular in an east^west direction. During late Campanian to early Maastrichtian time, widespread deposits of coarse sediment (the Hams Fork Conglomerate) aggraded the top of the thrust wedge after it stalled, prior to initiation of 'late'Absaroka thrusting. Meanwhile Megasequence 5 was deposited in the Wyoming foreland under the in£uence of both the intraforeland Wind River basement uplift and the Sevier thrust belt.

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Section: Methodsmentioning

confidence: 99%

Linkage of Sevier thrusting episodes and Late Cretaceous foreland basin megasequences across southern Wyoming (USA)

et al. 2005

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“…During the Jurassic-Cretaceous period, the combination of subsidence and tectono-eustatic highstand has led to the establishment of the Western Interior Basin (WIB), an elongated foreland marine basin (Kauffman, 1977;Hay et al, 1993) developed between the north American Cordilleran orogenic belt (Sevier Highlands) (Weimer, 1984;Jordan, 1991) and the north American craton (Caldwell and Kauffman, 1993) (Fig. 1C).…”

Section: Section Of Hot Springs (Cenomanian-turonian Stage Boundary mentioning

confidence: 99%

Reconstruction of the Nd isotope composition of seawater on epicontinental seas: Testing the potential of Fe–Mn oxyhydroxide coatings on foraminifera tests for deep-time investigations

Charbonnier¹,

Pucéat²,

Bayon³

et al. 2012

Geochimica et Cosmochimica Acta

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The Fe-Mn oxide fraction leached from deep-sea sediments has been increasingly used to reconstruct the Nd isotope composition of deep water masses, that can be used to track changes in oceanic circulation with a high temporal resolution. Application of this archive to reconstruct the Nd isotope composition of bottom seawater in shallow shelf environments remained however to be tested. Yet as the Nd isotope composition of seawater on continental margins is particularly sensitive to changes in erosional inputs, establishment of neritic seawater Nd isotope evolution around areas of deep water formation would be useful to discriminate the influence of changes in oceanic circulation and in isotopic composition of erosional inputs on the Nd isotope record of deep waters. The purpose of this study is to test the potential of Fe-Mn coatings leached from foraminifera tests to reconstruct the Nd isotope composition of seawater in shelf environments for deep-time intervals. Albian to Turonian samples from two different outcrops have been recovered, from the Paris Basin (Wissant section, northern France) and from the Western Interior Seaway (Hot Spring, South Dakota, USA), that were deposited in epicontinental seas. Rare Earth Element (REE) spectra enriched in middle REEs in the foraminifera leach at Wissant highlight the presence of Fe-Mn oxides. The similarity of the Nd isotopic signal of the Fe-Mn oxide fraction leached from foraminifera tests with that of fish teeth suggests that Fe-Mn oxides coating foraminifera can be good archives of shelf bottom seawater Nd isotopic composition. Inferred bottom shelf water Nd isotope compositions at Wissant range from À8.5 to À9.7 e-units, about 1.5-2 e-units higher than that of the contemporaneous local detrital fraction. At Hot Spring, linear REE spectra characterizing foraminifera leach may point to an absence of authigenic marine Fe-Mn oxide formation in this area during the Late 0016-7037/$ -see front matter Ó Geochimica et Cosmochimica Acta 99 (2012) [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] Cenomanian-Early Turonian, consistent with dysoxic to anoxic conditions at Hot Spring, contemporaneous to an Oceanic Anoxic Event. The similarity of the Nd isotopic signal of the carbonate matrix of foraminifera with that of fish teeth suggests that it records the Nd isotope composition of bottom shelf seawater as well. Inferred bottom shelf water Nd isotope compositions at Hot Spring are quite radiogenic, between À7 and À6 e-units, about 2.5-4 e-units higher than that of the contemporaneous local detrital fraction. In contrast, in both sections Fe-Mn oxides leached directly from the decarbonated sediment tend to yield a less radiogenic Nd isotopic composition, typically between 0.2 and 0.8 e-units lower, that is intermediate between that of fish teeth and of the detrital fraction. This suggests the contribution of pre-formed continental Fe-Mn oxides to the Nd isotopic signal, along with authigenic marine oxides, or a detrital contamination during leaching.

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“…Flexural subsidence of the basin in response to thrust-sheet loading has been established as the primary control on the wedge-shaped form of the basin fill (Price, 1973;Jordan, 1981). A number of workers have reasoned that episodic thrusting, and attendant changes in subsidence and sediment influx, may also have been important factors in the more detailed stratigraphic evolution of the Western Interior Seaway (Jordan, 1981;Weimer, 1984Weimer, , 1986Swift et al, 1987;Ryer, 1990;Jordan & Flemings, 1991;Vail et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

Stratigraphical architecture at the muddy margin of the Cretaceous Western Interior Seaway, southern Utah

Leithold

1994

Sedimentology

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The Tropic Shale and correlative Tununk Shale Member of the Mancos Shale accumulated during Cenomanian‐Turonian time, within prodeltaic environments near the western margin of the Western Interior Seaway of North America. Stratigraphical and sedimentological analysis has revealed a detailed history of relative sea level change in the thick, fine grained succession. The Tropic and Tununk shales were deposited during the Greenhorn second‐order sea level cycle, over a time span of about 2–5 million years. In southern Utah, six depositional sequences are superposed upon the record of this long term sea level change. The sequences developed during third‐order relative sea level cycles of hundreds of thousands of years duration and are composed of at least 37 parasequences, arranged in retrogradational, aggradational and progradational parasequence sets. The Tropic Shale and Tununk Shale Member accumulated just basinward of the axis of maximum subsidence of a foreland basin. Stratal geometries and facies distribution patterns in the succession indicate that in southern Utah the Greenhorn cycle was tectonically controlled. During the Greenhorn transgression and highstand, rapid rates of tectonic subsidence trapped terrigenous sediment to the west of the study area, in the more proximal foreland. At this time, hemipelagic facies accumulated at relatively slow rates in southern Utah and type 2 sequences developed during third‐order sea level cycles. In contrast, during the Greenhorn regression rates of thrust‐induced subsidence in the proximal foreland basin evidently slowed, and deltaic clinoforms prograded across the study area. At least one forced regression occurred in southern Utah at this time, and type 1 sequences developed. The formation of type 1 sequence boundaries in the upper part of the Tropic Shale and Tununk Shale Member points to episodes of base level fall and indicates that the six third‐order sea level cycles recorded in the succession were not the result of changes in sediment supply alone. The third‐order cycles may have been a consequence of episodic tectonism. The timing of these cycles, however, suggests that development of sequences and parasequences in the Tropic Shale and Tununk Shale Member may have been related to orbital forcing in the Milankovitch band. Glacioeustasy or climatically related fluctuations in the amount of groundwater stored on continents may explain these high frequency sea level changes.

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Relationship of Unconformities, Tectonics, and Sea Level Changes in the Cretaceous of the Western Interior, United States

Cited by 17 publications

References 0 publications

Linkage of Sevier thrusting episodes and Late Cretaceous foreland basin megasequences across southern Wyoming (USA)

Linkage of Sevier thrusting episodes and Late Cretaceous foreland basin megasequences across southern Wyoming (USA)

Reconstruction of the Nd isotope composition of seawater on epicontinental seas: Testing the potential of Fe–Mn oxyhydroxide coatings on foraminifera tests for deep-time investigations

Stratigraphical architecture at the muddy margin of the Cretaceous Western Interior Seaway, southern Utah

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