NORTH AMERICAN DETRITAL ZIRCON AGE DOMAINS AND SEDIMENT DISPERSAL PATTERNS

The Bell River hypothesis proposes that an ancestral, transcontinental river occupied much of northern North America during the Cenozoic Era, transporting water and sediment from the North American Cordillera to the Saglek Basin on the eastern margin of the Labrador Sea. To explore this hypothesis and reconstruct Cenozoic North American drainage patterns, we analyzed detrital zircon grains from the Oligocene−Miocene Mokami and Saglek formations of the Saglek Basin and Oligocene−Miocene fluvial conglomerates in the Great Plains of western Canada. U-Pb detrital zircon age populations in the Mokami and Saglek formations include clusters at <250 Ma, 950−1250 Ma, 1600−2000 Ma, and 2400−3200 Ma. Detrital zircons with ages of <250 Ma were derived from the North American Cordillera, supporting the transcontinental Bell River hypothesis. Oligocene−Miocene fluvial strata in western Canada contain detrital zircon age populations similar to those in the Saglek Basin and are interpreted to represent the western headwaters of the ancient Bell River drainage. Strontium-isotope ratios of marine shell fragments from the Mokami and Saglek formations yielded ages between 25.63 and 18.08 Ma. The same shells have εNd values of −10.2 to −12.0 (average = −11.2), which are consistent with values of Paleozoic strata in western North America but are more radiogenic than the modern Labrador Current, Labrador Sea Water, and North Atlantic Deep Water values (εNd ∼−12 to −25). As a freshwater source, the existence and termination of the Bell River may have been important for Labrador Sea circulation, stratification, and chemistry.

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Detrital Zircon U-Pb Geochronology and Provenance of the Sundance Formation, Western Powder River Basin, Wyoming

The Mountain Geologist ◽

10.31582/rmag.mg.56.3.295 ◽

2019 ◽

Vol 56 (3) ◽

pp. 295-317

Author(s):

Joseph Syzdek ◽

David Malone ◽

John Craddock

Keyword(s):

River Basin ◽

Detrital Zircon ◽

Habitat Management ◽

Wildlife Habitat ◽

Detrital Zircons ◽

Powder River Basin ◽

Zircon Age ◽

Sediment Dispersal ◽

Two Samples ◽

Management Area

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 Sevier-Laramide foreland. The Sundance in the western Powder River Basin consists of an oolitic limestone and green glauconitic sandstone at the base, green shales in the middle, and a yellow quartz arenite with coquina “oyster” beds at the top. U-Pb analyses of detrital zircons using LA-ICP-MS were conducted on two samples collected in the Bud Love Wildlife Habitat Management Area, 20 km northwest of Buffalo, WY. The two samples were taken from the upper and lower sandstone members of the Sundance Formation (n=289 concordant U-Pb zircon ages). The samples show a distinct difference in detrital zircon age spectra. The lower sandstone age spectrum ranges from 260-3172 Ma with 23% of the ages being Paleozoic, 71% being Proterozoic, and 6% being Archean. This lower stratum has detrital zircon age peaks at 343, 432, 686, 1039, 1431, 1662, 1748, 1941, 2433, and 3179 Ma. The lower sandstone shows an easterly Appalachian-Ouachita provenance, which persisted in the region beginning in the Carboniferous. In comparison to the upper strata, ages range from 157-2949 Ma and age peaks at 170, 243, 440, 545, 1082, 1467, 1681, and 1985 Ma. The maximum deposition age for the upper member is 160 Ma. Mesozoic aged grains make up 15.6% of the zircons, 14.7% were Paleozoic, 65.7% were Proterozoic, and 4% were Archean in age. The appearance of Mesozoic zircons in the upper sandstone marks the first significant appearance of westerly sourced zircons, and perhaps reflects the earliest uplift of the Sevier fold and thrust belt. Previous research has found this same signature in the Sundance but not in the underlying Triassic Chugwater Formation, resulting in a broad boundary of the change in sediment dispersal and the onset of the Sevier Orogeny between the Triassic and Jurassic. This study was conducted for a higher resolution to the provenance of the Sundance Formation and to further narrow the boundary of differing sedimentation from an eastern recycled to western synorogenic source.

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Detrital zircon record of magmatism and sediment dispersal across the North American Cordilleran arc system (28–48°N)

Earth-Science Reviews ◽

10.1016/j.earscirev.2021.103734 ◽

2021 ◽

pp. 103734

Author(s):

Theresa M. Schwartz ◽

Kathleen D. Surpless ◽

Joseph P. Colgan ◽

Samuel A. Johnstone ◽

Christopher S. Holm-Denoma

Keyword(s):

North American ◽

Detrital Zircon ◽

Sediment Dispersal ◽

The North

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Interpreting large detrital geochronology data sets in retroarc foreland basins: An example from the Magallanes-Austral Basin, southernmost Patagonia

Lithosphere ◽

10.1130/l1060.1 ◽

2019 ◽

Vol 11 (5) ◽

pp. 620-642 ◽

Cited By ~ 2

Author(s):

Zachary T. Sickmann ◽

Theresa M. Schwartz ◽

Matthew A. Malkowski ◽

Stephen C. Dobbs ◽

Stephan A. Graham

Keyword(s):

Multidimensional Scaling ◽

Detrital Zircon ◽

Foreland Basin ◽

Data Sets ◽

Foreland Basins ◽

Dispersal Patterns ◽

Data Set ◽

Sediment Dispersal ◽

Source Regions ◽

Provenance Data

Abstract The Magallanes-Austral retroarc foreland basin of southernmost South America presents an excellent setting in which to examine interpretive methods for large detrital zircon data sets. The source regions for retroarc foreland basins generally, and the Magallanes-Austral Basin specifically, can be broadly divided into (1) the magmatic arc, (2) the fold-and-thrust belt, and (3) sources around the periphery of foreland flexural subsidence. In this study, we used an extensive detrital zircon data set (30 new, 87 previously published samples) that is complemented by a large modal provenance data set of 183 sandstone petrography samples (32 new, 151 previously published) and rare earth element geochemical analyses (130 previously published samples) to compare the results of empirical (multidimensional scaling) and interpretive (age binning based on source regions) treatments of detrital zircon data, ultimately to interpret the detailed evolution of sediment dispersal patterns and their tectonic controls in the Magallanes-Austral Basin. Detrital zircon sample groupings based on both a priori age binning and multidimensional scaling are required to maximize the potential of the Magallanes-Austral Basin data set. Multidimensional scaling results are sensitive to differences in major unimodal arc-related U-Pb detrital zircon ages and less sensitive to differences in multimodal, thrust belt–related age peaks. These sensitivities complicate basin-scale interpretations when data from poorly understood, less densely sampled sectors are compared to data from better-understood, more densely sampled sectors. Source region age binning alleviates these biases and compares well with multidimensional scaling results when samples from the less well-understood southern basin sector are excluded. Sample groupings generated by both multidimensional scaling and interpretive methods are also compatible with compositional provenance data. Together, this integration of provenance data and methods facilitates a detailed interpretation of sediment dispersal patterns and their tectonic controls for the Late Cretaceous to Eocene fill of the Magallanes-Austral retroarc foreland basin. We interpret that provenance signatures and dispersal patterns during the retroarc foreland phase were fundamentally controlled by conditions set by a predecessor extensional basin phase, including (1) variable magnitude of extension with latitude, (2) the composition of lithologies emplaced on the antecedent western flank, and (3) long-lasting structural discontinuities associated with early rifting that may have partitioned dispersal systems or controlled the location of long-lived drainage networks.

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Detrital Zircon Geochronology of Pennsylvanian-Permian Strata in Colorado: Evidence for Appalachian-Derived Sediment and Implications for the Timing of Ancestral Rocky Mountains Uplift

The Mountain Geologist ◽

10.31582/rmag.mg.55.3.119 ◽

2018 ◽

Vol 55 (3) ◽

pp. 119-140 ◽

Cited By ~ 4

Author(s):

Kajal Nair ◽

John Singleton ◽

Christopher Holm-Denoma ◽

Sven Egenhoff

Keyword(s):

Detrital Zircon ◽

Detrital Zircons ◽

Sediment Provenance ◽

Front Range ◽

Sediment Sources ◽

Dispersal Patterns ◽

North Central ◽

Zircon Age ◽

Detrital Zircon Geochronology ◽

Appalachian Orogen

Pennsylvanian-Permian time in north-central Colorado corresponds with uplift of the Ancestral Front Range and deposition of the Fountain, Ingleside, and Lyons Formations along its flanks. In southwestern Colorado, deposition of the Molas and Hermosa Formations along the flanks of the Uncompahgre Highlands largely represents Pennsylvanian time. We present new detrital zircon U-Pb geochronology data for the Ingleside and Lyons Formations in north-central Colorado and the Molas and Hermosa Formations in southwestern Colorado to understand sediment provenance and dispersal patterns. We determined U-Pb ages using LA-ICPMS on 120-150 zircon grains from five sandstone samples collected from shallow marine and eolian facies within the Ingleside, Lyons, Molas, and Hermosa Formations. All sandstone samples display a mixed Laurentian derivation, with age populations that record local and distal sediment sources. All samples also contain between 5% and 10% concordant Paleozoic-age zircon grains ranging from 330–490 Ma, coinciding with high magmatic flux during the Taconic and Acadian orogenies in the Appalachian orogen. Ultimate derivation from the Appalachians are also interpreted for zircon age populations ranging from 500-750 Ma and 1000-1300 Ma that likely originated from Pan-African and Grenville terranes respectively. This study detects the earliest documented appearance of Paleozoic zircons along the northern Ancestral Front Range, corresponding to deposition of the lower Ingleside Formation. We compare our data along the Front Range to previous detrital zircon studies from the underlying Fountain Formation to conclude that the Fountain-Ingleside transition was accompanied by a decrease in locally sourced detrital zircons, most likely marking the cessation of Ancestral Front Range uplift. Conversely, deposition across the Molas-Hermosa contact in southwestern Colorado was accompanied by an increase in locally-sourced detrital zircon grains, most likely marking the initiation of the Uncompahgre uplift.

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Preliminary detrital zircon U-Pb Geochronology of the Wasatch Formation, Powder River Basin, Wyoming

The Mountain Geologist ◽

10.31582/rmag.mg.56.3.247 ◽

2019 ◽

Vol 56 (3) ◽

pp. 247-266

Author(s):

Ian Anderson ◽

David H. Malone ◽

John Craddock

Keyword(s):

River Basin ◽

Detrital Zircon ◽

Middle Part ◽

Detrital Zircons ◽

Powder River Basin ◽

Zircon Age ◽

Lower Eocene ◽

The North ◽

Mountain Front ◽

Fluvial Sandstone

The lower Eocene Wasatch Formation is more than 1500 m thick in the Powder River Basin of Wyoming. The Wasatch is a Laramide synorgenic deposit that consists of paludal and lacustrine mudstone, fluvial sandstone, and coal. U-Pb geochronologic data on detrital zircons were gathered for a sandstone unit in the middle part of the succession. The Wasatch was collected along Interstate 90 just west of the Powder River, which is about 50 km east of the Bighorn Mountain front. The sandstone is lenticular in geometry and consists of arkosic arenite and wacke. The detrital zircon age spectrum ranged (n=99) from 1433-2957 Ma in age, and consisted of more than 95% Archean age grains, with an age peak of about 2900 Ma. Three populations of Archean ages are evident: 2886.6±10 Ma (24%), 2906.6±8.4 Ma (56%) and 2934.1±6.6 Ma (20%; all results 2 sigma). These ages are consistent with the age of Archean rocks exposed in the northern part of the range. The sparse Proterozoic grains were likely derived from the recycling of Cambrian and Carboniferous strata. These sands were transported to the Powder River Basin through the alluvial fans adjacent to the Piney Creek thrust. Drainage continued to the north through the basin and eventually into the Ancestral Missouri River and Gulf of Mexico. The provenance of the Wasatch is distinct from coeval Tatman and Willwood strata in the Bighorn and Absaroka basins, which were derived from distal source (>500 km) areas in the Sevier Highlands of Idaho and the Laramide Beartooth and Tobacco Root uplifts. Why the Bighorn Mountains shed abundant Eocene strata only to the east and not to the west remains enigmatic, and merits further study.

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