scholarly journals Supplemental Material: Dating lacustrine carbonate strata with detrital zircon U-Pb geochronology

2020 ◽  
Author(s):  
Emily Finzel ◽  
Justin Rosenblume
Keyword(s):  
Detrital Zircon ◽  
Analytical Data ◽  
Lacustrine Carbonate

Detrital zircon U-Pb analytical data.<br>

scholarly journals Supplemental Material: Dating lacustrine carbonate strata with detrital zircon U-Pb geochronology

2020 ◽  
Author(s):  
Emily Finzel ◽  
Justin Rosenblume
Keyword(s):  
Detrital Zircon ◽  
Analytical Data ◽  
Lacustrine Carbonate

Detrital zircon U-Pb analytical data.<br>

Dating lacustrine carbonate strata with detrital zircon U-Pb geochronology

Geology ◽  
2020 ◽  
Author(s):  
Emily S. Finzel ◽  
Justin A. Rosenblume
Keyword(s):  
Detrital Zircon ◽  
Relative Proportion ◽  
Foreland Basin ◽  
Depositional Environments ◽  
Detrital Zircons ◽  
Sediment Flux ◽  
Coarse Grained ◽  
Southwestern Montana ◽  
Tectonically Active ◽  
Lacustrine Carbonate

Carbonate lacustrine strata in nonmarine systems hold great potential for refining depositional ages through U-Pb dating of detrital zircons. The low clastic sediment flux in carbonate depositional environments may increase the relative proportion of zircons deposited by volcanic air fall, potentially increasing the chances of observing detrital ages near the true depositional age. We present U-Pb geochronology of detrital zircons from lacustrine carbonate strata that provides proof of concept for the effectiveness of both acid-digestion recovery and resolving depositional ages of nonmarine strata. Samples were collected from Early Cretaceous foreland basin fluvial sandstone and lacustrine carbonate in southwestern Montana (USA). Late Aptian–early Albian (ca. 115–110 Ma) maximum depositional ages young upsection and agree with biostratigraphic ages. Lacustrine carbonate is an important component in many types of tectonic basins, and application of detrital zircon U-Pb geochronology holds considerable potential for dating critical chemical and climatic events recorded in their stratigraphy. It could also reveal new information for the persistent question about whether the stratigraphic record is dominated by longer periods of background fine-grained sedimentation versus short-duration coarse-grained events. In tectonically active basins, lacustrine carbonates may be valuable for dating the beginning of tectonic subsidence, especially during periods of finer-grained deposition dominated by mudrocks and carbonates.

U–Pb detrital zircon constraints on active margin magmatism and sedimentation after the Grampian Orogeny in western Ireland

2020 ◽  
pp. jgs2020-093
Author(s):  
Peter D. Clift ◽  
Amy L. Luther ◽  
Madison E. Avery ◽  
Paul B. O'Sullivan
Keyword(s):  
Detrital Zircon ◽  
Analytical Data ◽  
Sedimentary Rocks ◽  
Detrital Zircons ◽  
Upper Ordovician ◽  
Content Type ◽  
Igneous Intrusions ◽  
Supplementary Material ◽  
Western Ireland ◽  
Harbour Area

Early Ordovician collision of the Lough Nafooey Arc (part of the Baie Verte Oceanic Tract) with the passive continental margin of Laurentia peaked at c. 475 Ma in Scotland and Ireland and was followed by subduction polarity reversal. We examined Upper Ordovician–Silurian sedimentary rocks from western Ireland to see whether collision was followed by renewed arc magmatism. Despite the scarcity of dated igneous intrusions between the Grampian (c. 470 Ma) and Acadian (c. 420 Ma) orogenies in Ireland, detrital zircons show a continuity of activity peaking at 480–440 Ma, implying no hiatus in regional magmatism. Differences in zircon U–Pb age spectra highlight the isolation of basins in the southern Killary Harbour area from those north of the South Mayo Trough. These latter rocks were largely derived by erosion from Moine and Upper Dalradian sources. By contrast, the Killary Harbour Basin shows a decreasing influence from the Dalradian after c. 436 Ma and an increasing influence of contemporaneous magmatic zircons. These were transported from sources along-strike from the present NE, probably at the southern end of the Scandian Mountains in SE Greenland. The western Irish basins formed as pull-apart basins in a forearc setting and are analogous to Cenozoic pull-apart basins in Sumatra.Supplementary material: U-Pb zircon analytical data is available at a decreasing influence from the Dalradian after c. 436 Ma and an increasing influence of contemporaneous https://doi.org/10.6084/m9.figshare.c.5209849

scholarly journals Supplemental Material: Stratigraphy of the Eocene–Oligocene Titus Canyon Formation, Death Valley, California, and Eocene extensional tectonism in the Basin and Range

2021 ◽  
Author(s):  
N. Midttun ◽  
et al.
Keyword(s):  
Detrital Zircon ◽  
Large Scale ◽  
Analytical Data ◽  
Basin And Range ◽  
Death Valley ◽  
Data Table ◽  
Additional Explanation

<div>Text: Additional explanation of the methods used to recalculate the Ar/Ar ages of Gutenkunst (2006), Saylor and Hodges (1994), and Saylor (1991). Figure S1: Analytical plots recalculated from <sup>40</sup>Ar/<sup>39</sup>Ar data originally produced by Gutenkunst (2006). Figure S2: Scans of a large scale map and seven isochron plots for five samples provided by B. Saylor (personal commun., 2015). Table S1: Detrital zircon U-Pb analytical data. Table S2: Zircon (U‐Th)/He analytical data. Table S3: Analytical data for <sup>40</sup>Ar/<sup>39</sup>Ar ages of Gutenkunst (2006).<br></div>

scholarly journals Supplemental Material: Stratigraphy of the Eocene–Oligocene Titus Canyon Formation, Death Valley, California, and Eocene extensional tectonism in the Basin and Range

2022 ◽  
Author(s):  
N. Midttun ◽  
et al.
Keyword(s):  
Detrital Zircon ◽  
Large Scale ◽  
Analytical Data ◽  
Basin And Range ◽  
Death Valley ◽  
Data Table ◽  
Additional Explanation

<div>Text: Additional explanation of the methods used to recalculate the Ar/Ar ages of Gutenkunst (2006), Saylor and Hodges (1994), and Saylor (1991). Figure S1: Analytical plots recalculated from <sup>40</sup>Ar/<sup>39</sup>Ar data originally produced by Gutenkunst (2006). Figure S2: Scans of a large scale map and seven isochron plots for five samples provided by B. Saylor (personal commun., 2015). Table S1: Detrital zircon U-Pb analytical data. Table S2: Zircon (U‐Th)/He analytical data. Table S3: Analytical data for <sup>40</sup>Ar/<sup>39</sup>Ar ages of Gutenkunst (2006).<br></div>

Supplemental Material: Stratigraphy of the Eocene–Oligocene Titus Canyon Formation, Death Valley, California, and Eocene extensional tectonism in the Basin and Range

2021 ◽  
Author(s):  
N. Midttun ◽  
et al.
Keyword(s):  
Detrital Zircon ◽  
Large Scale ◽  
Analytical Data ◽  
Basin And Range ◽  
Death Valley ◽  
Data Table ◽  
Additional Explanation

<div>Text: Additional explanation of the methods used to recalculate the Ar/Ar ages of Gutenkunst (2006), Saylor and Hodges (1994), and Saylor (1991). Figure S1: Analytical plots recalculated from <sup>40</sup>Ar/<sup>39</sup>Ar data originally produced by Gutenkunst (2006). Figure S2: Scans of a large scale map and seven isochron plots for five samples provided by B. Saylor (personal commun., 2015). Table S1: Detrital zircon U-Pb analytical data. Table S2: Zircon (U‐Th)/He analytical data. Table S3: Analytical data for <sup>40</sup>Ar/<sup>39</sup>Ar ages of Gutenkunst (2006).<br></div>

scholarly journals Multiple sediment incorporation events in a continental magmatic arc: Insight from the metasedimentary rocks of the northern North Cascades, Washington (USA)

Geosphere ◽  
2021 ◽  
Author(s):  
Ann E. H. Hanson ◽  
Stacia M. Gordon ◽  
Kyle T. Ashley ◽  
Robert B. Miller ◽  
Elizabeth Langdon-Lassagne
Keyword(s):  
Detrital Zircon ◽  
Analytical Data ◽  
North Cascades ◽  
Detrital Zircon Geochronology ◽  
Magmatic Arc ◽  
Metasedimentary Rocks ◽  
The North ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

The rheology and composition of arc crust and the overall evolution of continental magmatic arcs can be affected by sediment incorporation events. The exhumed Cretaceous–Eocene North Cascades arc exposes abundant metasedimentary rocks that were incorporated into the arc during multiple events. This study uses field relationships, detrital zircon geochronology, bulk rock geochemistry, geothermometry, and quartz­in­garnet geobarometry to distinguish approximate contacts and emplacement depths for different metasedimentary units to better understand their protolith incorporation history and impact on the arc. The Skagit Gneiss Complex is one of the main deep crustal units of the North Cascades arc. It includes metasedimentary rocks with distinct detrital zircon signatures: Proterozoic–Cretaceous (Group 1) or Triassic–Cretaceous (Group 2) zircon populations. Both metasedimentary groups achieved near­ peak metamorphic conditions of 640–800 °C and 5.5–7.9 kbar; several Group 2 samples reveal the higher pressures. A third group of metasedimentary rocks, which was previously interpreted as metamorphosed equivalents of backarc sediments (Group 3), exhibited unimodal Triassic or bimodal Late Jurassic–Early Cretaceous detrital zircon signatures and achieved near­peak conditions of 570–700 °C and 8.7–10.5 kbar. The combined field and analytical data indicate that protoliths of Group 1 and Group 2 metasedimentary rocks were successively deposited in a forearc basin and underthrusted into the arc as a relatively coherent body. Group 3 backarc sediments were incorporated into the arc along a transpressional step­over zone. The incorporation of both forearc and backarc sediments was likely facilitated by arc magmatism that weakened arc crust in combination with regional transpression.

HREM interface studies in SiC-whisker-reinforced Al2O3 and Si3N4 ceramics

1988 ◽  
Vol 46 ◽  
pp. 734-735
Author(s):  
W. Braue ◽  
R.W. Carpenter ◽  
D.J. Smith
Keyword(s):  
Analytical Data ◽  
Base Material ◽  
High Strength ◽  
Ceramic Composites ◽  
Good Thermal Stability ◽  
All Ceramic ◽  
Sic Whiskers ◽  
Base Composite ◽  
C 30 ◽  
Si3n4 Ceramics

Whisker and fiber reinforcement has been established as an effective toughening concept for monolithic structural ceramics to overcome limited fracture toughness and brittleness. SiC whiskers in particular combine both high strength and elastic moduli with good thermal stability and are compatible with most oxide and nonoxide matrices. As the major toughening mechanisms - crack branching, deflection and bridging - in SiC whiskenreinforced Al2O3 and Si3N41 are critically dependent on interface properties, a detailed TEM investigation was conducted on whisker/matrix interfaces in these all-ceramic- composites.In this study we present HREM images obtained at 400 kV from β-SiC/α-Al2O3 and β-SiC/β-Si3N4 interfaces, as well as preliminary analytical data. The Al2O3- base composite was hotpressed at 1830 °C/60 MPa in vacuum and the Si3N4-base material at 1725 °C/30 MPa in argon atmosphere, respectively, adding a total of 6 vt.% (Y2O3 + Al2O3) to the latter to promote densification.

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