U-Pb Detrital Zircon Geochronology of Lower Cretaceous Cedar Mountain and San Pitch Formations in Central-eastern, Utah PDF Download
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Author: Gary J. Hunt
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 238
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Book Description
The distribution of U-Pb ages of detrital zircons from synorogenic Lower Cretaceous (Barremain-Albian) Cedar Mountain and San Pitch formation conglomerates and sandstones (N = 7, n = 641) preserved in the Sevier foreland basin of Utah are statistically related to age spectra of detrital zircons in Jurassic-Neoproterozoic strata (N = 11, n = 1104) in the Cordilleran fold-thrust belt. A history of Sevier thrust-belt unroofing, reworking, and recycling of detritus is recorded in the distribution of detrital zircons in Lower Cretaceous foreland basin strata. Three geochronological provenance intervals are observed in Neoproterozoic-Jurassic strata in the thrust-belt that are also recognized in 3 inverted chronofacies in foreland basin strata. The first provenance interval in the thrust belt is recognized as chronofacies A in the foreland basin. It is defined by a dominant group of Paleoproterozoic detrital zircons and the presence of significant numbers of Late Neoproterozic-Early Paleozoic (550 - 300 Ma) grains. Quartzites and sandstones in the thrust belt in provenance interval 1 include Pennsylvanian-Permain Oquirrh Formation, Permian Diamond Creek Sandstone, and the Jurassic Nugget Sandstone. Statistically related to provenance interval 1 are the oldest foreland basin strata in chronofacies A, including the Buckhorn Conglomerate Member of the Cedar Mountain Formation on the San Rafael Swell, and the Yellow Cat and Poison Strip Sandstone members in eastern Utah. The second provenance is observed in Ordovician-Devonian strata in the Canyon Range thrust sheet, and chronofacies B in the foreland basin; these display mostly Paleoproterozoic detrital zircons with dominant age groups of 1.8-1.9 Ga and 2.2-2.4 Ga. Cedar Mountain Formation conglomerates at the base of the Cretaceous succession in Salina Canyon on the southwestern Wasatch Plateau, and the Short Canyon Conglomerate (Upper Albain) on the western San Rafael Swell, are statistically related to detrital zircon age spectra observed in the Eureka (Ordovician) and Cove Fort (Devonian) quartzites in the thrust-belt. The third provenance interval observed constitutes Neoproterozoic and Cambrian quartzites from the Canyon Range thrust sheet and chronofacies C in the foreland basin, which all produce a tri-modal population of Mesoproterozoic (1.0-1.2 Ga), Paleoproterozoic (1.4 Ga and 1.6-1.8 Ga), and a subordinate population of Archean (>2.5 Ga) grains. Upper Albian conglomerates of the San Pitch Formation produced detrital zircon grains that were derived primarily from the oldest allochthonous strata in the thrust sheet, thus recording the complete unroofing of the thrust-belt in Early Cretaceous time. Abundant Mesozoic detrial zircon grains were sampled in distal Cedar Mountain Formation samples, whereas in more proximal deposits of the Buckhorn Conglomerate on the San Rafael Swell, Cordilleran arc grains are rare. This is due to different sediment dispersal patterns and involves recycling of detrital zircons from reworked Mesozoic strata and perhaps transported directly from Jurassic plutons in the southern Mogollon Highlands. The Buckgorn Conglomerate was deposited by braided transverse rivers with headwaters in the Sevier highlands that produce minimal Triassic-Jurassic detrital zircons, whereas distal deposits of the Yellow Cat and Poison Strip Sandstone members were deposited in a distal axial river system with headwaters in the Mogollon highlands where Triassic-Jurassic zircons are plentiful. Three stages of the early Cretaceous foreland basin in Utah are recognized. An initial stage, which was controlled predominantly by dynamic subsidence, is recognized by the slow deposition of Barremian-Aptian strata of the lower Cedar Mountain Formation (e.g. Buckhorn Conglomerate) with no evidence of a clastic wedge developement to the west. The second stage is the observance of the first westward thickening wedge of sediment recognized in Aptian-Albian Cedar Mountain Formation (Ruby Ranch Member); this indicates that the flexural component of the foreland basin began in Late Aptian or later.The final stage of Early Cretaceous thrust-belt unroofing is recognized with deposition of the San Pitch Formation on proximal axial rivers in an actively subsiding foredeep depozone during latest Albian time.
Author: Gary J. Hunt
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 238
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Book Description
The distribution of U-Pb ages of detrital zircons from synorogenic Lower Cretaceous (Barremain-Albian) Cedar Mountain and San Pitch formation conglomerates and sandstones (N = 7, n = 641) preserved in the Sevier foreland basin of Utah are statistically related to age spectra of detrital zircons in Jurassic-Neoproterozoic strata (N = 11, n = 1104) in the Cordilleran fold-thrust belt. A history of Sevier thrust-belt unroofing, reworking, and recycling of detritus is recorded in the distribution of detrital zircons in Lower Cretaceous foreland basin strata. Three geochronological provenance intervals are observed in Neoproterozoic-Jurassic strata in the thrust-belt that are also recognized in 3 inverted chronofacies in foreland basin strata. The first provenance interval in the thrust belt is recognized as chronofacies A in the foreland basin. It is defined by a dominant group of Paleoproterozoic detrital zircons and the presence of significant numbers of Late Neoproterozic-Early Paleozoic (550 - 300 Ma) grains. Quartzites and sandstones in the thrust belt in provenance interval 1 include Pennsylvanian-Permain Oquirrh Formation, Permian Diamond Creek Sandstone, and the Jurassic Nugget Sandstone. Statistically related to provenance interval 1 are the oldest foreland basin strata in chronofacies A, including the Buckhorn Conglomerate Member of the Cedar Mountain Formation on the San Rafael Swell, and the Yellow Cat and Poison Strip Sandstone members in eastern Utah. The second provenance is observed in Ordovician-Devonian strata in the Canyon Range thrust sheet, and chronofacies B in the foreland basin; these display mostly Paleoproterozoic detrital zircons with dominant age groups of 1.8-1.9 Ga and 2.2-2.4 Ga. Cedar Mountain Formation conglomerates at the base of the Cretaceous succession in Salina Canyon on the southwestern Wasatch Plateau, and the Short Canyon Conglomerate (Upper Albain) on the western San Rafael Swell, are statistically related to detrital zircon age spectra observed in the Eureka (Ordovician) and Cove Fort (Devonian) quartzites in the thrust-belt. The third provenance interval observed constitutes Neoproterozoic and Cambrian quartzites from the Canyon Range thrust sheet and chronofacies C in the foreland basin, which all produce a tri-modal population of Mesoproterozoic (1.0-1.2 Ga), Paleoproterozoic (1.4 Ga and 1.6-1.8 Ga), and a subordinate population of Archean (>2.5 Ga) grains. Upper Albian conglomerates of the San Pitch Formation produced detrital zircon grains that were derived primarily from the oldest allochthonous strata in the thrust sheet, thus recording the complete unroofing of the thrust-belt in Early Cretaceous time. Abundant Mesozoic detrial zircon grains were sampled in distal Cedar Mountain Formation samples, whereas in more proximal deposits of the Buckhorn Conglomerate on the San Rafael Swell, Cordilleran arc grains are rare. This is due to different sediment dispersal patterns and involves recycling of detrital zircons from reworked Mesozoic strata and perhaps transported directly from Jurassic plutons in the southern Mogollon Highlands. The Buckgorn Conglomerate was deposited by braided transverse rivers with headwaters in the Sevier highlands that produce minimal Triassic-Jurassic detrital zircons, whereas distal deposits of the Yellow Cat and Poison Strip Sandstone members were deposited in a distal axial river system with headwaters in the Mogollon highlands where Triassic-Jurassic zircons are plentiful. Three stages of the early Cretaceous foreland basin in Utah are recognized. An initial stage, which was controlled predominantly by dynamic subsidence, is recognized by the slow deposition of Barremian-Aptian strata of the lower Cedar Mountain Formation (e.g. Buckhorn Conglomerate) with no evidence of a clastic wedge developement to the west. The second stage is the observance of the first westward thickening wedge of sediment recognized in Aptian-Albian Cedar Mountain Formation (Ruby Ranch Member); this indicates that the flexural component of the foreland basin began in Late Aptian or later.The final stage of Early Cretaceous thrust-belt unroofing is recognized with deposition of the San Pitch Formation on proximal axial rivers in an actively subsiding foredeep depozone during latest Albian time.
Author: Douglas A. Sprinkel
Publisher: Utah Geological Survey
ISBN: 1557918635
Category : Dinosaur National Monument (Colo. and Utah)
Languages : en
Pages : 25
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Book Description
This 20 page report describes the stratigraphy of the Cedar Mountain and Dakota formations in and around Dinosaur National Monument in northeast Utah and includes new palynology and radiometric age data. The contract between these formations is unconformable in which the Dakota formation has incised into the underlying Cedar Mountain formation. Locally, the Dakota includes a basal marine mudstone and shale unit that contains late Albian dinoflagellate cysts, which represents peak sea level during the Kiowa-Skull Creek depositional cycle and indicates the first marine incursion of the Cretaceous Western Interior Seaway into Utah.
Author: Douglas A. Sprinkel
Publisher: Utah Geological Survey
ISBN: 1557916438
Category : Science
Languages : en
Pages : 26
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Book Description
Lower Cretaceous strata exposed in the foreland basin of central Utah were divided into two lithostratigraphic units, the Cedar Mountain and San Pitch Formations. Together these formations correlate with both the Cedar Mountain Formation exposed on the San Rafael Swell and the lower part of the Canyon Range Conglomerate exposed in the Canyon Mountains.
Author: Cody John Stopka
Publisher:
ISBN:
Category :
Languages : en
Pages : 500
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Book Description
The Cordilleran foreland basin is located in the western part of North America and stretches from the Canadian Arctic to parts of southern Mexico and was active from the Late Jurassic to Late Cretaceous. Presented here are U-Pb detrital zircon ages, sandstone modal composition, and paleocurrent measurements from Upper Cretaceous (Cenomanian- Campanian) nonmarine strata of the Dakota Sandstone, Tres Hermanos Formation, and Crevasse Canyon Formation (Lower Member and Ash Canyon Member) located in the southernmost portions of the Sevier foreland basin in southern New Mexico. The Dakota Sandstone is dominated by monocrystalline quartz (84%) with volcanic and metamorphic lithic grains (15%). Paleoflow trends show east-directed (108°) to northeast-directed flow (50°). Detrital zircon age peaks occur at 1732, 1651, 1416, 1050, 626, 412, 230, and 103 Ma. The Tres Hermanos Formation is composed primarily of monocrystalline quartz (63%) with volcanic and metamorphic lithic grains (27%). Paleoflow trends predominantly reflect east-directed (93-109°) and southeast-directed (166°) flow. Peak detrital zircon ages occur at 1709, 1420, 1085, 169, and 94 Ma. The Lower Member of the Crevasse Canyon Formation is composed of monocrystalline quartz (50%) along with volcanic and metamorphic lithic grains (41%). Paleoflow trends show primarily east-directed flow (100°). Detrital zircon age peaks occur at 1702, 1420, 1067, 167, and 91 Ma. The Ash Canyon Member of the Crevasse Canyon Formation is composed of monocrystalline quartz (48%) with volcanic and metamorphic lithic grains (46%). Paleoflow trends show a east- to southeast-directed flow (108-118°). Peak detrital zircon ages were determined to be 1682, 1415, 1108, 169 and 90 Ma. Precambrian to Paleozoic zircons overlap in age with the Yavapai, Mazatzal, Granite-Rhyolite, and Grenville provinces (and age-equivalent ~1.0 Ga rocks), and recycled Neoproterozoic and Early Paleozoic detritus from Mesozoic eolianites of the southwest United States. Permian to Triassic age detritus overlap in age with granitoid rocks that outcrop in California and Arizona. Jurassic to Cretaceous age zircons overlap with the mid-Mesozoic Cordilleran magmatic arc and the Sierra Nevada batholith. Based on the provenance trends summarized above, a sediment dispersal model is favored where the Dakota Sandstone was derived largely from recycled Lower Cretaceous strata of the Bisbee Rift of southeastern Arizona and southwestern New Mexico (present-day Mogollon highlands). Overlying strata of the Tres Hermanos and Crevasse Canyon Formations were sourced primarily from Jurassic-Cretaceous parts of the Cordilleran arc with secondary contributions from recycled strata of the Bisbee Rift and possible the McCoy basin of southern Arizona and southwestern New Mexico.
Author: Preston James Wahl
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Sediment delivery to Texas and the northwestern Gulf of Mexico during the Early Paleogene represents an initial cycle of tectonic-influenced deposition that corresponds with the timing of late Laramide uplift. Sediments shed from Laramide uplifts to east-central Texas and the northwestern Gulf of Mexico during this time are preserved in strata of the Wilcox Group and lower Claiborne Group. U-Pb dating of detrital zircons from closely spaced stratigraphic units within these groups and the underlying Midway Group by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) reveals the relative arrival time of late Laramide-age detrital zircons to east-central Texas and distinct detrital zircon age assemblages. Comparison of zircon age assemblages from this study with data from potential source regions and additional Wilcox and Claiborne Group samples along the Texas and Louisiana Gulf Coastal Plain provides insight into paleodrainage during the Early Paleogene. The relative arrival time of late Laramide-age detrital zircons to east-central Texas corresponds with deposition of the Hooper Formation of the Wilcox Group, although the presence of these detrital zircons fluctuates within younger samples. Comparison of composite detrital zircon age spectra from sediment source regions and from locations along the Texas and Louisiana Gulf Coastal Plain shows that source regions contain unique distributions of ages, with age components that are similar to Gulf Coastal Plain data. Detrital zircon age data may support relatively similar sediment sources or a similar paleodrainage area for the majority of observed ages within the Midway Group, Wilcox Group, and Carrizo Formation in east-central Texas. Louisiana Wilcox Group and east-central Texas (Tehuacana Member through Carrizo Formation) data are similar and contrast with data of the south Texas Wilcox Group. This may support similar paleodrainage for Louisiana and east-central Texas and a different paleodrainage to the south Texas area. Data may also support the introduction of a new sediment source or a greater contribution of detrital zircons from an already existing source by the time of Queen City Formation (lower Claiborne Group) deposition in east-central Texas. Comparison of Louisiana Claiborne Group data with east-central Texas Queen City Formation data indicates that this source was also available during deposition of younger Claiborne Group strata in Louisiana. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155424
Author: Hirotsugu Mori
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 102
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Book Description
The Cedar Mountain Formation contains the most diverse record of Early Cretaceous dinosaurs in the western hemisphere. However, analyses of its faunas have been hindered because 1) most taxa are based on incomplete/fragmentary materials or incomplete descriptions, 2) most sites and some horizons preserve few taxa, and 3) the stratigraphy and geochronology are poorly understood.
Author: Genevive R. Mathers
Publisher:
ISBN: 9781109765090
Category : Climatic changes
Languages : en
Pages : 140
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Book Description
There are a number of distinctive, penecontemporaneous, regionally distributed conglomeratic units in the central and southern U.S. Rocky Mountains whose origin and relationship to regional tectonics, climate change and basin evolution are unclear. These units - the Dark Canyon sequence of the Wasatch Formation in the Book Cliffs of Utah, the Ohio Creek Member of the Mesaverde Group in the Piceance Creek Basin of Colorado, the Arapahoe Conglomerate of the Denver Formation (D1 sequence) in the Denver Basin, the Canaan Peak Formation in the Kaiparowits Plateau of southwestern Utah, and the Ojo Alamo Formation in the San Juan Basin of Colorado and New Mexico - are generally thin and widespread, and abruptly prograde out across underlying units. They are broadly similar in composition, containing dominantly chert and quartzite clasts reworked from local Mesozoic and Paleozoic sources; they were deposited by gravelly river systems; they are unconformity-bounded; and they were all deposited at or around the Cretaceous/Paleogene boundary. While these units have been broadly dated using palynology, interpretation of their origins has been difficult given the scarcity of sample material and the large age ranges for some recovered palynomorphs. Young peak ages of U-Pb detrital zircon spectra, interpreted to represent a maximum depositional age, are used in conjunction with traditional basin analysis techniques and published age data to determine the depositional history of these conglomeratic units. Subsidence analysis indicates that the latest Cretaceous and early Paleogene were times of reduced subsidence rates in these basins, and that the conglomerates were deposited after the initiation of Laramide-related subsidence in these basins, or late-stage Sevier thrusting in the case of the Canaan Peak Formation. While reported ages of deposition of these units cover a large time span, it is permissible that deposition was synchronous between ~66 and ~64 Ma, given the overlap between published ages and U-Pb dates of detrital zircons. The overall similarities in depositional style and timing suggest that gravel dispersal at the Cretaceous/Paleogene boundary could have been a result of regional climate change. Published Global Climate Models and stable isotope studies suggest that the Rocky Mountain monsoon had begun on the eastern flanks of the Sevier belt by the Campanian and had moved east to the broken Laramide foreland by the Paleogene. The depositional model proposed by this study concludes that a period of tectonic quiescence in the rising Laramide uplifts, evidenced by a reduction in subsidence rates and basin-wide unconformities, in latest Cretaceous and early Paleogene time led to overall reduced subsidence rates that, when coupled with an abrupt increase in seasonal precipitation during the Rocky Mountain monsoon, promoted a basinward shift in facies and created erosional surfaces in the proximal parts of basins. Renewed tectonism and subsidence in late Paleocene through Eocene time caused a subsequent retraction of lithofacies, leading to onlap of coarse-grained material (the conglomerates in this study) onto these erosional surfaces and subsequent deposition of finer-grained deposits. Thus, tectonics coupled with climate change lead to the deposition of the widespread conglomerates found around the Cretaceous/Paleogene boundary in the central and southern Rocky Mountains.
Author: U.S. Department of the Interior
Publisher: CreateSpace
ISBN: 9781496083180
Category : Reference
Languages : en
Pages : 40
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Book Description
Ages of detrital zircons are reported from ten samples of Lower Cretaceous to Paleogene metasandstones and sandstones from the Chugach Mountains, Talkeetna Mountains, and western Alaska Range of south-central Alaska. Zircon ages are also reported from three igneous clasts from two conglomerates. The results bear on the regional geology, stratigraphy, tectonics, and mineral resource potential of the southern Alaska convergent margin.
Author: Timothy Frost Lawton
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 50
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Book Description
Author: Roger D. Miller
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The Early Cretaceous (Barremian-Albian) Burro Canyon Formation in Eastern Utah and Western Colorado is a dominantly fluvial system that resembles the Cedar Mountain Formation, a correlative unit that lies across the Colorado River and is famous for recent dinosaur discoveries, The Burro Canyon Formation is arbitrarily split from the Cedar Mountain Formation using the Colorado River as a dividing line. This non-stratigraphic means of splitting one unit from the other is largely due to convention and it has become entrenched in the literature. Sections measured on Hotel Mesa and Buckhorn Mesa, both in eastern Grand County, Utah, were made in order to better delineate the contact between the two formations in this remote area on the Uncompahgre Plateau. The section on Hotel Mesa is in the Poison Strip Sandstone Member of the Cedar Mountain Formation as demonstrated by correlation to nearby established measured sections. Multiple paleocurrents were taken on Buckhorn Mesa, along with three new measured sections. These measured sections and paleoflows were then used to determine whether these rocks are likely to be in the Burro Canyon Formation or the Cedar Mountain Formation. Facies were established for the outcrops, with preliminary facies associations then being developed and outlined on photographs. Analyses show that these fluvial sandstones on this edge of the Uncompahgre Plateau are all in the Poison Strip Sandstone Member of the Cedar Mountain Formation. Also, no other Early Cretaceous sediments are found on this entire portion of the Plateau, as illustrated using panoramic photographs.
