Detrital Zircon U-Pb geochronology of the Ordovician Lander Sandstone, Bighorn

2019 ◽  
Vol 56 (3) ◽  
pp. 231-246 ◽  
Author(s):  
J. D. McGuire ◽  
David Malone ◽  
John Craddock ◽  
Shawn J. Malone

The Ordovician Lander Sandstone, which occurs unconformably above the Cambrian Gallatin Limestone and beneath the Bighorn Dolomite, occurs in the Bighorn, Powder, and Wind River basins of Wyoming. The Lander ranges from 0-10 m in thickness and consists of texturally and compositional mature, cross bedded quartz arenite. This study uses detrital zircon U-Pb geochronology to elucidate its provenance. Samples were collected from two localities along the eastern flank of the Bighorn Mountains near Buffalo, Wyoming: a roadcut on US 16 just west of the Clear Creek thrust and from along Crazy Woman Canyon Road. The results showed a statistical similarity between the two samples, and that zircon ages are predominantly Proterozoic in age (~75%) while the minority ages were Archean (25%). Probability density plots of the two-source areas show that the peak ages for Crazy Woman Canyon (n=90) are ~1840, 2075 and 2695 Ma and the US 16 peak ages (n=141) are ~1825, 2075, and 2725 Ma. The detrital zircon age spectra for these samples indicate that the Lander was not derived from local Archean basement and was not recycled from the underlying Cambrian. The Lander has a provenance in either the Trans-Hudson Province and adjacent rocks in present day Saskatchewan and Manitoba more than 1000 km to the north or from the Peace River Arch, an early Paleozoic highlands in northwestern Alberta and northeastern British Columbia. The Lander zircons have a similar provenance to eolian zircons in the Bighorn Dolomite and to other Ordovician sandstones on the Cordilleran Continental margin and central Idaho. The Lander provenance is distinct from the Ordovician St. Peter Sandstone, which occurs extensively east of the Transcontinental Arch. We interpret that the Lander was derived on the late Ordovician shoreline, and then transported via prevailing winds across the Laurentian shelf from east to west during sea level low stand, and then distributed throughout the shelf by currents.

2019 ◽  
Vol 56 (3) ◽  
pp. 247-266
Author(s):  
Ian Anderson ◽  
David H. Malone ◽  
John Craddock

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.


2016 ◽  
Vol 448 (1) ◽  
pp. 145-159 ◽  
Author(s):  
Tianchen He ◽  
Ying Zhou ◽  
Pieter Vermeesch ◽  
Martin Rittner ◽  
Lanyun Miao ◽  
...  

2013 ◽  
Vol 150 (6) ◽  
pp. 1103-1126 ◽  
Author(s):  
DETA GASSER ◽  
ARILD ANDRESEN

AbstractThe tectonic origin of pre-Devonian rocks of Svalbard has long been a matter of debate. In particular, the origin and assemblage of pre-Devonian rocks of western Spitsbergen, including a blueschist-eclogite complex in Oscar II Land, are enigmatic. We present detrital zircon U–Pb LA-ICP-MS data from six Mesoproterozoic to Carboniferous samples and one U–Pb TIMS zircon age from an orthogneiss from Oscar II Land in order to discuss tectonic models for this region. Variable proportions of Palaeo- to Neoproterozoic detritus dominate the metasedimentary samples. The orthogneiss has an intrusion age of 927 ± 3 Ma. Comparison with detrital zircon age spectra from other units of similar depositional age within the North Atlantic region indicates that Oscar II Land experienced the following tectonic history: (1) the latest Mesoproterozoic sequence was part of a successor basin which originated close to the Grenvillian–Sveconorwegian orogen, and which was intruded byc. 980–920 Ma plutons; (2) the Neoproterozoic sediments were deposited in a large-scale basin which stretched along the Baltoscandian margin; (3) the eclogite-blueschist complex and the overlying Ordovician–Silurian sediments probably formed to the north of the Grampian/Taconian arc; (4) strike-slip movements assembled the western coast of Spitsbergen outside of, and prior to, the main Scandian collision; and (5) the remaining parts of Svalbard were assembled by strike-slip movements during the Devonian. Our study confirms previous models of complex Caledonian terrane amalgamation with contrasting tectonic histories for the different pre-Devonian terranes of Svalbard and particularly highlights the non-Laurentian origin of Oscar II Land.


2017 ◽  
Vol 54 (2) ◽  
pp. 69-85 ◽  
Author(s):  
David Malone ◽  
John Craddock ◽  
Kacey Garber ◽  
Jarek Trela

The Aycross Formation is the basal unit of the Absaroka Volcanic Supergroup in the southern Absaroka Range and consists of volcanic sandstone, mudstone, breccia, tuff and conglomerate. The Aycross was deposited during the waning stages of the Laramide Orogeny and the earliest phases of volcanism in the Absaroka Range. U-Pb geo-chronology using laser ablation multicollector inductively coupled plasma mass spectrometry LA-ICP-MS was performed on detrital zircons collected from an Aycross sandstone bed at Falls Campground east of Togwotee Pass. The detrital zircon age spectrum ranged fom ca 47 to 2856 Ma. Peak ages, as indicated by the zircon age probability density plot are ca. 51, 61, and 72 Ma. Tertiary zircons were the most numerous (n = 32), accounting for 42% of the zircon ages spectrum. Of these 19 are Eocene, and 13 are Paleocene, which are unusual ages in the Wyoming-Idaho-Montana area. Mesozoic zircons (n = 21) comprise 27% of the age spectrum and range in age from 68–126 Ma; all but one being late Cretaceous in age. No Paleozoic zircons are present. Proterozoic zircons range in age from 1196–2483 Ma, and also consist of 27% of the age spectrum. The maximum depositional age of the Aycross Formation is estimated to be 50.05 +/− 0.65 Ma based on weighted mean of the eight youngest grains. The Aycross Formation detrital zircon age spectrum is distinct from that of other 49–50 Ma rocks in northwest Wyoming, which include the Hominy Peak and Wapiti Formations and Crandall Conglomerate. The Aycross must have been derived largely from distal westerly source areas, which include the late Cretaceous and Paleocene Bitteroot Lobe of the Idaho Batholith. In contrast, the middle Eocene units further to the north must have been derived from erosion of the Archean basement-cored uplift of the Laramide Foreland in southwest Montana.


1985 ◽  
Vol 22 (9) ◽  
pp. 1299-1313 ◽  
Author(s):  
Kory R. Koke ◽  
C. R. Stelck

The discovery of the arenaceous foraminifer Haplophragmoides gigas Cushman in the Hudson Hope area of northeastern British Columbia indicates that the Early Cretaceous (Albian) Joli Fou Sea flooded around the north side of the Peace River Arch, making an embayment that penetrated as far west as the Rocky Mountain Foothills. The microfauna of 25 genera and 46 species of arenaceous foraminifers is illustrated carrying Bathysiphon spp., Hippocrepina sp., Hyperammina spp., Lituotuba? sp., Psammosphaera spp., Reophax spp., Ammodiscus spp., Glomospira sp., Miliammina spp., Psamminopelta spp., Trochamminoides sp., Haplophragmoides spp., Ammomarginulina sp., Ammobaculites spp., Haplophragmium spp., Trochammina spp., Textulariopsis sp., Pseudobolivina spp., Plectorecurvoides sp., Verneuilina sp., Gaudryina sp., Uvigerinammina sp., Gravellina sp., and Eggerella sp.The suite occurs in the lower part of the Hasler Shale of the Fort St. John Group about 10–20 m above beds carrying a microfauna of the Ammobaculites wenonahae Subzone (= Stelckiceras liardense ammonite Zone) present in the basal portion of the Hasler Shale. The Haplophragmoides gigas Zone sensu stricto is overlain by a sequence of silty beds (Viking equivalent?), which in turn is succeeded by the Miliammina manitobensis Zone microfauna. The H. gigas assemblage has both boreal and southern aspects, suggesting a mixing of the waters from north and south as the first expression of the Colorado Sea in earliest late Albian time. The assemblage is a deep neritic one and lacks any calcareous component. Diagnostic megafauna are lacking.


Author(s):  
Julia I. Corradino ◽  
Alex Pullen ◽  
Andrew L. Leier ◽  
David L. Barbeau Jr. ◽  
Howie D. Scher ◽  
...  

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.


2019 ◽  
Vol 56 (3) ◽  
pp. 295-317
Author(s):  
Joseph Syzdek ◽  
David Malone ◽  
John Craddock

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.


2017 ◽  
Vol 54 (2) ◽  
pp. 104-124 ◽  
Author(s):  
David Malone ◽  
John Craddock ◽  
Jessica Welch ◽  
Brady Foreman

We report the results of U-Pb ages from detrital zircon populations in the lower Eocene synorogenic Willwood Formation in the northern Absaroka Basin, Wyoming. Zircons (n=229) were extracted from three sandstone beds and one ash layer in the Willwood Formation at the base of Jim Mountain in the North Fork Shoshone River Valley. K-S statistical analysis indicates that the three sandstones, which were sampled from the base, middle, and top of the formation, have identical age spectra, indicating that the sandstone provenance remained the same during the duration of Willwood deposition. The zircon age spectra are dominated by Archean zircons (61%), with peak ages at 3270 and 2770 Ma. These sandstones also have very early Paleoproterozoic zircons (∼2450 Ma), which likely were derived from the Tobacco Root Mountains. The final significant age peak is ∼70 Ma, which is likely associated with the Cretaceous Tobacco Root batholith. The Jim Mountain ash, which occurs at the top of the succession, just beneath the allocthonous volcanic rocks of the Heart Mountain slide, has a maximum depositional age of ∼50 Ma. Between 49–50 Ma, as Eocene volcanism in the northern Absaroka Range became more prominent, stratovolcanoes grew and disrupted sediment transport into the Absaroka basin. Lower Wapiti sandstones to the southwest show a mix of Eocene, recycled Proterozoic and Archean grains. The coeval Crandall Conglomerate, which was dismembered by the emplacement of the Heart Mountain slide in the northern Absaroka Range, has a distinct detrital zircon age spectrum. Thus these stream systems that deposited the Crandall did not share the headwaters with the streams that supplied sediment to the Absaroka basin.


2011 ◽  
Vol 62 (4) ◽  
pp. 299-307 ◽  
Author(s):  
Ion Balintoni ◽  
Constantin Balica ◽  
Antoneta Seghedi ◽  
Mihai Ducea

Peri-Amazonian provenance of the Central Dobrogea terrane (Romania) attested by U/Pb detrital zircon age patterns The Central Dobrogea Shield is a part of the Moesia, a Paleozoic composite terrane located southward of the North Dobrogea Alpine orogen. The two geological units are separated from each other by a trans-lithospheric discontinuity, the Peceneaga-Camena transform fault. Along this fault, remnants of a Variscan orogen (i.e. North Dobrogea), recycled during the Alpine orogeny come in contact with two lithological entities of the Central Dobrogea Shield, unaffected by the Phanerozoic orogenic events: the Histria Formation, a flysch-like sequence of Ediacaran age very low-grade metamorphosed and its basement, the medium-grade metamorphosed Altîn Tepe sequence. Southward, along the reverse hidden Palazu fault, the Histria Formation meets South Dobrogea, formed of quite different geological formations. Detrital zircon from the Histria Formation yielded U/Pb LA ICP MS ages that show provenance patterns typical of peri-Amazonian terranes. Such terranes were sourced by orogens ranging from Paleoarchean to Neoproterozoic. The ages between 750 and 600 Ma differentiate the Amazonian sources from the Baltican and Laurentian sources, since they are lacking from the last ones. The youngest ages of 587 and 584 Ma suggest for the Histria Formation a maximum late Ediacaran deposition age. At the same time, the continuity of the Ordovician sediments over the Palazu fault revealed by drill-cores favours a Cambrian junction between Central and South Dobrogea.


2010 ◽  
Vol 47 (11) ◽  
pp. 1383-1404 ◽  
Author(s):  
Reed S. Lewis ◽  
Jeffrey D. Vervoort ◽  
Russell F. Burmester ◽  
Peter J. Oswald

The authors analyzed detrital zircon grains from 10 metasedimentary rock samples of the Priest River complex and three other amphibolite-facies metamorphic sequences in north-central Idaho to test the previous assignment of these rocks to the Mesoproterozoic Belt–Purcell Supergroup. Zircon grains from two samples of the Prichard Formation (lower Belt) and one sample of Cambrian quartzite were also analyzed as controls with known depositional ages. U–Pb zircon analysis by laser ablation — inductively coupled plasma — mass spectrometry reveals that 6 of the 10 samples contain multiple age populations between 1900 and 1400 Ma and a scatter of older ages, similar to results reported from the Belt–Purcell Supergroup to the north and east. Results from the Priest River metamorphic complex confirm previous correlations with the Prichard Formation. Samples from the Golden and Elk City sequences have significant numbers of 1500–1380 Ma grains, which indicates that they do not predate the Belt. Rather, they are probably from a relatively young, southwestern part of the Belt Supergroup (Lemhi subbasin). Non-North American (1610–1490 Ma) grains are rare in these rocks. Three samples of quartzite from the Syringa metamorphic sequence northwest of the Idaho batholith contain zircon grains younger than the Belt Supergroup and support a Neoproterozoic age. A single Cambrian sample has abundant 1780 Ma grains and none younger than ∼1750 Ma. These results indicate that the likely protoliths of many high-grade metamorphic rocks in northern Idaho were strata of the Belt–Purcell Supergroup or overlying rocks of the Neoproterozoic Windermere Supergroup and not basement rocks.


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