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Artigos de revistas sobre o tema "U-Pb zircon geochronology"

Autor: Grafiati

Publicado: 4 de junho de 2021

Última modificação: 31 de janeiro de 2023

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1

Kusiak, Monika A., Daniel J. Dunkley, Richard Wirth, Martin J. Whitehouse, Simon A. Wilde, and Katharina Marquardt. "Metallic lead nanospheres discovered in ancient zircons." Proceedings of the National Academy of Sciences 112, no. 16 (2015): 4958–63. http://dx.doi.org/10.1073/pnas.1415264112.

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Zircon (ZrSiO4) is the most commonly used geochronometer, preserving age and geochemical information through a wide range of geological processes. However, zircon U–Pb geochronology can be affected by redistribution of radiogenic Pb, which is incompatible in the crystal structure. This phenomenon is particularly common in zircon that has experienced ultra-high temperature metamorphism, where ion imaging has revealed submicrometer domains that are sufficiently heterogeneously distributed to severely perturb ages, in some cases yielding apparent Hadean (>4 Ga) ages from younger zircons. Docum

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2

Bowring, Samuel A., Blair Schoene, James L. Crowley, Jahandar Ramezani, and Daniel J. Condon. "High-Precision U-Pb Zircon Geochronology and the Stratigraphic Record: Progress and Promise." Paleontological Society Papers 12 (October 2006): 25–45. http://dx.doi.org/10.1017/s1089332600001339.

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High-precision geochronological techniques have improved in the past decade to the point where volcanic ash beds interstratified with fossil-bearing rocks can be dated to a precision of 0.1% or better. The integration of high-precision U-Pb zircon geochronology with bio/chemo-stratigraphic data brings about new opportunities and challenges toward constructing a fully calibrated time scale for the geologic record, which is necessary for a thorough understanding of the distribution of time and life in Earth history. Successful implementation of geochronology as an integral tool for the paleontol

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3

Xie, Lie-Wen, Jin-Hui Yang, Qing-Zhu Yin, Yue-Heng Yang, Jing-Bo Liu, and Chao Huang. "High spatial resolution in situ U–Pb dating using laser ablation multiple ion counting inductively coupled plasma mass spectrometry (LA-MIC-ICP-MS)." Journal of Analytical Atomic Spectrometry 32, no. 5 (2017): 975–86. http://dx.doi.org/10.1039/c6ja00387g.

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A new LA-MIC-ICP-MS analytical technique has been developed for the rapid measurement of <sup>206</sup>Pb/<sup>238</sup>U zircon age (<1%, 2s) at a high spatial resolution. We show that this technique can be routinely employed to date U–Pb in small and/or complex zircons, providing a powerful tool for geochronology.

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4

Davies, Joshua H. F. L., Jörn-Frederik Wotzlaw, Alexander P. Wolfe, and Larry M. Heaman. "Assessing the age of the Late Cretaceous Danek Bonebed with U–Pb geochronology." Canadian Journal of Earth Sciences 51, no. 11 (2014): 982–86. http://dx.doi.org/10.1139/cjes-2014-0136.

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An ash-rich volcaniclastic sandstone immediately underlying dinosaur-rich material from the Danek Bonebed in the Horseshoe Canyon Formation (HCF), Edmonton, Alberta, Canada, contains accessory zircon, which have been dated employing U–Pb geochronology. Both laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and chemical abrasion isotope dilution thermal ionization mass spectrometry (ID-TIMS) U–Pb analyses have been conducted. The zircon age distributions are complex with U–Pb dates ranging from Precambrian to Cretaceous. We consider the youngest ID-TIMS 206Pb/238U date of

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5

Williams, Ian S. "Some observations on the use of zircon U-Pb geochronology in the study of granitic rocks." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 83, no. 1-2 (1992): 447–58. http://dx.doi.org/10.1017/s0263593300008129.

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ABSTRACTIn situ, microscale, U-Pb isotopic analyses of zircon using the SHRIMP ion microprobe demonstrate both the potential and the limitations of zircon U-Pb geochronology. Most zircons, whether from igneous or metamorphic rocks, need to be considered as mixed isotopic systems. In simple, young igneous rocks the mixing is principally between isotopically disturbed and undisturbed zircon. In polymetamorphic rocks, several generations of zircon growth can coexist, each with a different pattern of discordance. A similar situation exists for igneous rocks rich in inherited zircon, as these conta

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6

Sepahi, Ali A., Hamed Vahidpour, David R. Lentz, et al. "Rare sapphire-bearing syenitoid pegmatites and associated granitoids of the Hamedan region, Sanandaj–Sirjan zone, Iran: analysis of petrology, lithogeochemistry and zircon geochronology / trace element geochemistry." Geological Magazine 157, no. 9 (2020): 1499–525. http://dx.doi.org/10.1017/s0016756820000023.

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AbstractPegmatites and associated granitoids are integral parts of the Alvand plutonic complex in the Sanandaj–Sirjan zone, Iran. Whole rock major- and trace-element lithogeochemistry together with zircon U–Pb geochronology and zircon geochemistry are examined to evaluate the petrogenesis of sapphire-bearing pegmatites and other peraluminous pegmatites in the region. Pegmatites vary in their chemical compositions from mostly peraluminous, high-K calc-alkaline to shoshonitic signatures. A rare variety of extremely peraluminous sapphire-bearing syenitoid pegmatite (Al2O3 > 30 wt %; A/CNK >

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Jackson, William T., Matthew P. McKay, Donald A. Beebe, et al. "Late Cretaceous sediment provenance in the eastern Gulf Coastal Plain (U.S.A.) based on detrital-zircon U-Pb ages and Th/U values." Journal of Sedimentary Research 91, no. 10 (2021): 1025–39. http://dx.doi.org/10.2110/jsr.2020.177.

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ABSTRACT Detrital-zircon U-Pb geochronology documents a regional- to continental-scale drainage reorganization along the eastern Gulf Coastal Plain (USA) from the Late Cretaceous (Cenomanian) to the Paleocene–Eocene. We present detrital-zircon U-Pb ages and Th/U values from the Maastrichtian Ripley Formation to determine the sedimentary provenance and to provide spatiotemporal resolution of drainage reorganization. The Ripley Formation contains a 12.7% overall average abundance of detrital zircons with low (&lt; 0.1) Th/U values relative to the underlying Cenomanian Tuscaloosa Group (3.6%)

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8

Dunning, G. R. "U/Pb geochronology of the Coney Head Complex, Newfoundland." Canadian Journal of Earth Sciences 24, no. 5 (1987): 1072–75. http://dx.doi.org/10.1139/e87-104.

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The Coney Head Complex, White Bay, Newfoundland, comprises allochthonous plutonic rocks and deformed equivalents emplaced over the continental margin during the Ordovician Taconic Orogeny. A U/Pb zircon age of 474 + 2 Ma for tonalite considered as having formed by partial melting in an island arc, indicates that it crystallized in Arenig time. A microgranite dated by U/Pb (zircon + titanite) at 432 ± 2 Ma cuts the tonalite Inherited Proterozoic zircon in the microgranite indicates that the rock formed from magma generated in part by melting of continental crust or sediments derived from such c

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9

Pidgeon, R. T., A. A. Nemchin, and S. L. Kamo. "Comparison of structures in zircons from lunar and terrestrial impactitesThis article is one of a series of papers published in this Special Issue on the theme of Geochronology in honour of Tom Krogh." Canadian Journal of Earth Sciences 48, no. 2 (2011): 107–16. http://dx.doi.org/10.1139/e10-037.

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There have been a number of reports of the presence of shock features, such as planar fracturing and granulation, the transformation of zircon to reidite, and the breakdown of zircon to baddeleyite in zircons associated with terrestrial impacts. It has also been proposed that the progressive development of these shock features, and the degree of disturbance of the zircon U–Pb isotopic system, could be used as a qualitative measure of the shock pressures and post-shock temperatures of the impact. Such behaviour of zircon from terrestrial impacts could be potentially useful in interpreting struc

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10

Gehrels, George. "Detrital Zircon U-Pb Geochronology Applied to Tectonics." Annual Review of Earth and Planetary Sciences 42, no. 1 (2014): 127–49. http://dx.doi.org/10.1146/annurev-earth-050212-124012.

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WANG, JIALIN, CHAODONG WU, ZHUANG LI, et al. "The tectonic evolution of the Bogda region from Late Carboniferous to Triassic time: evidence from detrital zircon U–Pb geochronology and sandstone petrography." Geological Magazine 155, no. 5 (2017): 1063–88. http://dx.doi.org/10.1017/s0016756816001217.

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AbstractField-based mapping, sandstone petrology, palaeocurrent measurements and zircon cathodoluminescence images, as well as detrital zircon U–Pb geochronology were integrated to investigate the provenance of the Upper Carboniferous – Upper Triassic sedimentary rocks from the northern Bogda Mountains, and further to constrain their tectonic evolution. Variations in sandstone composition suggest that the Upper Carboniferous – Lower Triassic sediments displayed less sedimentary recycling than the Middle–Upper Triassic sediments. U–Pb isotopic dating using the LA-ICP-MS method on zircons from 1

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12

McGuire, J. D., David Malone, John Craddock, and Shawn J. Malone. "Detrital Zircon U-Pb geochronology of the Ordovician Lander Sandstone, Bighorn." Mountain Geologist 56, no. 3 (2019): 231–46. http://dx.doi.org/10.31582/rmag.mg.56.2.231.

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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 C

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13

Corfu, F., T. E. Krogh, and L. D. Ayres. "U–Pb zircon and sphene geochronology of a composite Archean granitoid batholith, Favourable Lake area, northwestern Ontario." Canadian Journal of Earth Sciences 22, no. 10 (1985): 1436–51. http://dx.doi.org/10.1139/e85-150.

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U–Pb zircon and sphene data for several phases of composite batholiths in the Favourable Lake area of the Superior Province indicate two major periods of plutonism separated by a hiatus of over 200 Ma.A trondhjemite, which now forms a metamorphosed remnant within a batholith, was emplaced 2950 ± 5 Ma ago during an early plutonic event. The second and dominant plutonic period occurred between [Formula: see text] and 2711.0 ± 2.0 Ma ago; these are the ages of the earliest and the latest widespread phase of the batholiths, respectively. Ages of 2716.3 ± 1.4 and 2716 ± 4 Ma for zircons of two mino

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14

Dunning, G. R., and T. E. Krogh. "Geochronology of ophiolites of the Newfoundland Appalachians." Canadian Journal of Earth Sciences 22, no. 11 (1985): 1659–70. http://dx.doi.org/10.1139/e85-174.

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Precise U/Pb zircon ages (2σ errors) are reported for four ophiolite complexes from the Newfoundland Appalachians.Zircons from trondhjemite from Blow Me Down Mountain, Bay of Islands Complex, give an age of [Formula: see text] (five points). Those from gabbro from Blow Me Down Brook give a minimum 207Pb/206Pb age of 480 Ma (one point), confirming that this is the age of the main plutonic episode. These data refute previously determined latest Cambrian U/Pb zircon and Sm/Nd (mineral–rock isochron) ages of 504 ± 10 and 505 Ma for the complex.Gabbro from the Betts Cove Complex yielded zircon that

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15

Matteini, Massimo, Elton L. Dantas, Marcio M. Pimentel, and Bernhard Bühn. "Combined U-Pb and Lu-Hf isotope analyses by laser ablation MC-ICP-MS: methodology and applications." Anais da Academia Brasileira de Ciências 82, no. 2 (2010): 479–91. http://dx.doi.org/10.1590/s0001-37652010000200023.

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The Lutetium-Hafnium isotopic system represents one of the most innovative and powerful tools for geochronology and isotopic studies. Combined U-Pb and Lu-Hf in situ analyses on zircon by LA-MC-ICP-MS permit to characterize isotopically the host magma from which it crystallized furnishing significant information for sediment provenance and crustal evolution studies. In this paper e describe the Lu-Hf systematic by LA-MC-ICP-MS developed in the laboratory of Geochronology of the University of Brasilia and report the results obtained by repeated analyses of 176Hf/177Hf isotopic ratio of three zi

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16

Carson, C. J., S. D. Boger, C. M. Fanning, C. J. L. Wilson, and D. E. Thost. "SHRIMP U–Pb geochronology from Mount Kirkby, northern Prince Charles Mountains, East Antarctica." Antarctic Science 12, no. 4 (2000): 429–42. http://dx.doi.org/10.1017/s0954102000000523.

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Sensitive High Resolution Ion MicroProbe (SHRIMP) U–Pb zircon dating of pegmatites from Mount Kirkby, northern Prince Charles Mountains, east Antarctica indicates felsic intrusive activity at 991 ± 22 Ma and 910 ± 18 Ma. Pegmatite emplacement occurred during prolonged high-grade early Neoproterozoic tectonism. These ages correlate well with previously published U–Pb zircon ages obtained from felsic intrusive bodies elsewhere within the northern Prince Charles Mountains. Early Palaeozoic activity at Mount Kirkby is restricted to the emplacement of minor planar pegmatites at 517 ± 12 Ma, which p

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17

Liu, Chao, Xiangdong Chang, Beilei Sun, and Fangui Zeng. "New Insight into the Depositional Age of No. 6 Coal in Heidaigou Mine, Late Paleozoic Jungar Coalfield, Inner Mongolia, China." Sustainability 14, no. 10 (2022): 6297. http://dx.doi.org/10.3390/su14106297.

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Coal deposits can provide novel stratigraphic markers for reconstructing the evolution history of a sedimentary basin and correlating sedimentary successions. Age dating was conducted on zircons harvested from the No. 6 coal seam within the Heidaigou Mine, Inner Mongolia. Two-kilogram samples were taken, and the recovered zircons were analyzed for U–Pb isotopic and rare earth elements (REE). The REE results of the zircon grains showed that all the zircon grains were enriched in heavy rare earth elements (HREE) but depleted in light rare earth elements (LREE). In addition, zircons from the No.

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18

Zhao, Wenhao, Qiuli Li, Yu Liu, et al. "Long-Term Reproducibility of SIMS Zircon U-Pb Geochronology." Journal of Earth Science 33, no. 1 (2022): 17–24. http://dx.doi.org/10.1007/s12583-021-1549-1.

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Horvat, Marija, Urs Klötzli, Domagoj Jamičić, György Buda, Eva Klötzli, and Christoph Hauzenberger. "Geochronology of granitoids from Psunj and Papuk Mts., Croatia." Geochronometria 45, no. 1 (2018): 198–210. http://dx.doi.org/10.1515/geochr-2015-0099.

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Abstract Detailed cathodoluminescence (CL) and back scattered electron (BSE) imaging of zircon crystals, coupled with in-situ U-Pb zircon dating by Laser Ablation Multi-Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) were used to develop new insights into the evolution of a monzogranite from Omanovac Quarry (Psunj Mt.), and of monzogranites from Šandrovac Quarry and Kišeljevac Creek (Papuk Mt.), both located in the Slavonian Mountains (Croatia). U-Pb isotopic data yielded a concordia age of 380 ± 4 Ma for the monzogranite from Omanovac Quarry, and 382 ± 2 Ma and 383 ± 5 M

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20

Leary, Ryan J., M. Elliot Smith, and Paul Umhoefer. "Mixed eolian–longshore sediment transport in the late Paleozoic Arizona shelf and Pedregosa basin, U.S.A.: A case study in grain-size analysis of detrital-zircon datasets." Journal of Sedimentary Research 92, no. 8 (2022): 676–94. http://dx.doi.org/10.2110/jsr.2021.101.

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ABSTRACT Detrital-zircon U–Pb geochronology has revolutionized sediment provenance studies over the last two decades, and zircon has been successfully analyzed from nearly all sedimentary lithologies, depositional environments, and sediment grain sizes. However, despite the ubiquity of this method and the far-reaching interpretations supported by detrital-zircon data, few studies have investigated the potential role of zircon grain size on age spectra and provenance interpretation. In this study, we investigate the connections between sample grain size, zircon grain size, U–Pb age spectra, and

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Greig, C. J., and G. E. Gehrels. "U–Pb zircon geochronology of Lower Jurassic and Paleozoic Stikinian strata and Tertiary intrusions, northwestern British Columbia." Canadian Journal of Earth Sciences 32, no. 8 (1995): 1155–71. http://dx.doi.org/10.1139/e95-095.

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New U–Pb zircon ages are reported from western Stikinia. Devonian and Pennsylvanian ages of volcanic rocks at Oweegee dome confirm the presence of pre-Permian strata, and with Paleozoic and Triassic detrital zircons from Lower Jurassic sandstone, they help to demonstrate pre-Lower Jurassic deformation and uplift. The absence of pre-Paleozoic inherited zircon from all samples is consistent with Nd–Sr isotopic data which suggest that Stikinia consists mainly of juvenile crust. U–Pb ages for posttectonic intrusions suggest that structures in Skeena Fold Belt in the Kinskuch area formed prior to E

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22

Yan, Taotao, Dongsheng Liu, Chen Si, and Yu Qiao. "Coupled U–Pb Geochronology of Monazite and Zircon for the Bozhushan Batholith, Southeast Yunnan Province, China: Implications for Regional Metallogeny." Minerals 10, no. 3 (2020): 239. http://dx.doi.org/10.3390/min10030239.

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Constraining the duration of magmatism is of vital importance to the understanding of the magmatic-hydrothermal mineral system. The Bozhushan batholith, located in the middle section of the southeastern Yunnan ore district, mainly consists of biotite monzogranite and monzogranite. Many Sn–W–polymetallic deposits are developed around the Bozhushan batholith, but their temporal and genetic relationships remain controversial. LA-ICP-MS U–Pb zircon and monazite dating were respectively conducted on the same two samples, yielding weighted mean 206Pb/238U zircon ages of 85.1 ± 0.7 and 85.6 ± 0.9 Ma,

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McGuire, Joseph D., John P. Craddock, David H. Malone, and Shawn J. Malone. "Detrital zircon U-Pb geochronology of the Ordovician Lander Sandstone, Bighorn Mountains, Wyoming." Mountain Geologist 56, no. 3 (2019): 231–46. http://dx.doi.org/10.31582/rmag.mg.56.3.231.

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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 C

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24

Large, Simon J. E., Jörn-Frederik Wotzlaw, Marcel Guillong, Albrecht von Quadt, and Christoph A. Heinrich. "Resolving the timescales of magmatic and hydrothermal processes associated with porphyry deposit formation using zircon U–Pb petrochronology." Geochronology 2, no. 2 (2020): 209–30. http://dx.doi.org/10.5194/gchron-2-209-2020.

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Abstract. Understanding the formation of economically important porphyry Cu–Au deposits requires knowledge of the magmatic-to-hydrothermal processes that act within the much larger magmatic system and the timescales on which they occur. We apply high-precision zircon geochronology (chemical abrasion–isotope dilution–thermal ionisation mass spectrometry; CA–ID–TIMS) and spatially resolved zircon geochemistry (laser ablation inductively coupled plasma mass spectrometry; LA-ICP-MS) to constrain the magmatic evolution of the underlying magma reservoir at the Pliocene Batu Hijau porphyry Cu–Au depo

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Verhaegen, Jasper, Hilmar von Eynatten, István Dunkl, and Gert Jan Weltje. "Detrital zircon geochronology and heavy mineral analysis as complementary provenance tools in the presence of extensive weathering, reworking and recycling: the Neogene of the southern North Sea Basin." Geological Magazine 158, no. 9 (2021): 1572–84. http://dx.doi.org/10.1017/s0016756821000133.

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AbstractHeavy mineral analysis is a long-standing and valuable tool for sedimentary provenance analysis. Many studies have indicated that heavy mineral data can also be significantly affected by hydraulic sorting, weathering and reworking or recycling, leading to incomplete or erroneous provenance interpretations if they are used in isolation. By combining zircon U–Pb geochronology with heavy mineral data for the southern North Sea Basin, this study shows that the classic model of sediment mixing between a northern and a southern source throughout the Neogene is more complex. In contrast to th

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Dinh, Sang Quang. "PETROGRAPHIC CHARACTERISTICS AND ZIRCON U-PB GEOCHRONOLOGY OF GRANITOID ROCKS IN THE SOUTHERN BÊN GIANG, QUNG NAM PROVINCE." Science and Technology Development Journal 14, no. 4 (2011): 17–30. http://dx.doi.org/10.32508/stdj.v14i4.2024.

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The early Palaeozoic calc-alkaline granitoid association in south Nam Giang town is forming large area reaching hundreds of km2, along the east – west ductile deformation zones, which is studied in detail in diffirent geologic maps scales by the geologists (Huynh Trung and Nguyen Xuan Bao, 1981 at 1:500,000 scale or Nguyen Van Trang et al, 1986, at 1:200,000 scale). The six samples were studied in details, which are composed mainly quartz diorite and granodiorite. The samples were crushed and large zircons were extracted. The laser ablation microprobe-inductively coupled plasma mass spectromet

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Scott, J. M. J., T. D. Peterson, W. J. Davis, C. W. Jefferson, and B. L. Cousens. "Petrology and geochronology of Paleoproterozoic intrusive rocks, Kiggavik uranium camp, Nunavut." Canadian Journal of Earth Sciences 52, no. 7 (2015): 495–518. http://dx.doi.org/10.1139/cjes-2014-0153.

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We investigated the age and petrology of Paleoproterozoic granitic intrusions in the area of the Kiggavik uranium exploration camp, near the southeast margin of the Aberdeen subbasin of the Thelon Basin. A subset of these intrusions (e.g., the Lone Gull stock) is spatially associated with and mineralized by basement hosted, unconformity-related uranium deposits. Surface (outcrop) samples have field relations, textures, and compositions consistent with Hudson Suite granitoids and mixtures of monzogranite with minette. We obtained U–Pb (zircon) ages ranging from ca. 1818 to 1840 Ma, within the k

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Skublov, Sergey G., Aleksey V. Berezin, Xian-Hua Li, et al. "Zircons from a Pegmatite Cutting Eclogite (Gridino, Belomorian Mobile Belt): U-Pb-O and Trace Element Constraints on Eclogite Metamorphism and Fluid Activity." Geosciences 10, no. 5 (2020): 197. http://dx.doi.org/10.3390/geosciences10050197.

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This report presents new data on U-Pb geochronology, oxygen isotopes, and trace element composition of zircon from a pegmatite vein crosscutting an eclogite boudin on Stolbikha Island, Gridino area, Belomorian mobile belt (BMB). The zircon grains occur as two distinct populations. The predominant population is pegmatitic and shows dark cathodoluminescence (CL); about a third of this population contains inherited cores. The second zircon population is typical of granulite and exhibits a well-defined sectorial (mosaic) zoning in CL. Both the inherited cores and sectorial in CL zircons appear to

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Kelly, C. J., D. A. Schneider, M. È. Lajoie, S. E. Jackson, and C. R. McFarlane. "U–Pb geochronology and trace element composition of zircon from the Horseshoe Lake greenstone belt, Superior Province, Canada: implications for the tectonic and metamorphic history." Canadian Journal of Earth Sciences 55, no. 2 (2018): 172–87. http://dx.doi.org/10.1139/cjes-2017-0079.

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Depth profile techniques for U–Pb geochronology and rare earth element (REE) geochemistry were conducted on unpolished, Archean zircon with metasomatic rims from metasedimentary rocks within the Horseshoe Lake greenstone belt, western Superior Province, Canada. These zircon crystals are shown to have isotopically distinct rims (typically <5 μm thick) compared with the interiors of the crystal. Secondary ion mass spectrometry (SIMS) U–Pb depth profile analyses of the rims define two different 207Pb/206Pb age populations at ca. 2920 and 2869 Ma, which are >100 million years younger than th

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Stevenson, R., G. L. Cumming, and D. Krstic. "Lead-isotope geochronology of the Portman Lake area, Northwest Territories." Canadian Journal of Earth Sciences 24, no. 11 (1987): 2188–96. http://dx.doi.org/10.1139/e87-207.

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An area of Archean rocks extending from northwestern Saskatchewan into the Northwest Territories is referred to as the Nolan block.Whole rocks and minerals separated from granodiorite surrounding an occurrence of amazonite at Portman Lake in the centre of this block have been studied in some detail using several dating techniques. The following ages result: [Formula: see text] on abraded zircons from the granodiorite; 2589 ± 4 Ma whole-rock Pb/Pb age of the granodiorite; 2561 ± 6 and 2475 ± 13 Ma internal Pb/Pb isochrons; and 2610 ± 10 Ma Pb/Pb model ages on galena and amazonite.Pb/Pb internal

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Malone, David, John Craddock, Jessica Welch, and Brady Foreman. "Detrital Zircon U-Pb geochronology and provenance of the Eocene Willwood Formation, Northern Absaroka Basin, Wyoming." Mountain Geologist 54, no. 2 (2017): 104–24. http://dx.doi.org/10.31582/rmag.mg.54.2.104.

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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 zirco

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Syzdek, Joseph, David Malone, and John Craddock. "Detrital Zircon U-Pb Geochronology and Provenance of the Sundance Formation, Western Powder River Basin, Wyoming." Mountain Geologist 56, no. 3 (2019): 295–317. http://dx.doi.org/10.31582/rmag.mg.56.3.295.

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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

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33

von Quadt, Albrecht, Jörn-Frederik Wotzlaw, Yannick Buret, Simon J. E. Large, Irena Peytcheva, and Anne Trinquier. "High-precision zircon U/Pb geochronology by ID-TIMS using new 1013 ohm resistors." Journal of Analytical Atomic Spectrometry 31, no. 3 (2016): 658–65. http://dx.doi.org/10.1039/c5ja00457h.

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34

Bowring, S. A. "High-Precision U-Pb Zircon Geochronology and the Stratigraphic Record." Reviews in Mineralogy and Geochemistry 53, no. 1 (2003): 305–26. http://dx.doi.org/10.2113/0530305.

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35

Crowley, J. L., S. A. Bowring, S. Z. Shen, Y. Wang, C. Cao, and Y. G. Jin. "U–Pb zircon geochronology of the end-Permian mass extinction." Geochimica et Cosmochimica Acta 70, no. 18 (2006): A119. http://dx.doi.org/10.1016/j.gca.2006.06.152.

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36

Xie, Z., J. F. Chen, and H. M. Li. "Zircon U-Pb geochronology of the Dabie-Sulu orogenic belt." Chinese Science Bulletin 43, S1 (1998): 147. http://dx.doi.org/10.1007/bf02891635.

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Magee, Charles, Jim Ferris, and Charles Magee. "Effect of impact energy on SIMS U-Pb zircon geochronology." Surface and Interface Analysis 46, S1 (2014): 322–25. http://dx.doi.org/10.1002/sia.5629.

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38

Vetrov, Evgeny, Johan De Grave, Natalia Vetrova, et al. "Tectonic History of the South Tannuol Fault Zone (Tuva Region of the Northern Central Asian Orogenic Belt, Russia): Constraints from Multi-Method Geochronology." Minerals 10, no. 1 (2020): 56. http://dx.doi.org/10.3390/min10010056.

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In this study, we present zircon U/Pb, plagioclase and K-feldspar 40Ar/39Ar and apatite fission track (AFT) data along the South Tannuol Fault Zone (STFZ). Integrating geochronology and multi-method thermochronology places constraints on the formation and subsequent reactivation of the STFZ. Cambrian (~510 Ma) zircon U/Pb ages obtained for felsic volcanic rocks date the final stage of STFZ basement formation. Ordovician (~460–450 Ma) zircon U/Pb ages were obtained for felsic rocks along the structure, dating their emplacement and marking post-formational local magmatic activity along the STFZ.

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39

Turek, A., Patrick E. Smith, and D. T. A. Symons. "U–Pb geochronology of the Coldwell Complex, northwestern Ontario, Canada." Canadian Journal of Earth Sciences 22, no. 4 (1985): 621–26. http://dx.doi.org/10.1139/e85-062.

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The Coldwell Complex gives a U–Pb zircon age of 1188 ± 56 Ma, a U–Pb tritomite age of 1126 ± 6 Ma, and a Pb–Pb potash feldspar age of 1139 ± 55 Ma. These ages are all significantly older than the previously published Rb–Sr and K–Ar ages. We interpret these ages as follows: (1) emplacement of the complex at 1188 Ma as part of the initial stages of the Keweenawan rifting event at depth; (2) slow cooling leading to closure of the U and Pb systems in tritomite and potash feldspar between 1139 and 1126 Ma; and (3) continued slow cooling leading to closure of the Rb–Sr system in the complex at an av

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40

Magee Jr., Charles W., Martin Danišík, and Terry Mernagh. "Extreme isotopologue disequilibrium in molecular SIMS species during SHRIMP geochronology." Geoscientific Instrumentation, Methods and Data Systems 6, no. 2 (2017): 523–36. http://dx.doi.org/10.5194/gi-6-523-2017.

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Abstract. The current limitation in the accuracy and precision of inter-element analysis in secondary ion mass spectrometry (SIMS) is the ability to find measurable quantities that allow relative differences in ionization and transmission efficiency of secondary ions to be normalized. In uranium–thorium–lead geochronology, the ability to make these corrections, or "calibrate" the data, results in an accuracy limit of approximately 1 %. This study looks at the ionization of uranium and thorium oxide species, which are traditionally used in U–Pb calibration, to explore the conditions under which

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41

Gehrels, George E. "Detrital zircon geochronology of the Taku terrane, southeast Alaska." Canadian Journal of Earth Sciences 39, no. 6 (2002): 921–31. http://dx.doi.org/10.1139/e02-002.

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UPb geochronologic studies have been conducted on 60 detrital zircon grains from Permian(?) and Triassic metasandstones of the Taku terrane in central southeast Alaska. The resulting ages are mainly in the range 349387 Ma, with five additional grains that yield probable ages ranging from ~906 to ~2643 Ma. These ages are similar to the ages of detrital zircons in Carboniferous and older rocks of the YukonTanana terrane, which lies directly east of the Taku terrane. In contrast, these ages are different from the ages of detrital zircon grains in the Alexander terrane to the west. The data are

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42

Krasnobaev, A. A., P. M. Valizer, and A. L. Perchuk. "ORDOVICIAN AGE OF DUNITE-WEHRLITE-CLINOPYROXENITE BENDED COMPLEX OF NURALI MASSIF (SOUTHERN URALS, RUSSIA): SHRIMP U-PB ZIRCON DATING." Moscow University Bulletin. Series 4. Geology, no. 1 (February 28, 2018): 60–70. http://dx.doi.org/10.33623/0579-9406-2018-1-60-70.

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We present the data of geochemistry and geochronology of zircons from wehrlites and clinopyroxenites from dunite-wehrlite-clinopyroxenite bended complex of the base of crustal section of ophiolite Nurali massif. The U-Pb age of the bended complex is 450±4 Ma which is different from the previous data. Zircons from the studied rocks have complimentary REE patterns and similar U-Pb ages to lherzolites and dunites from mantle section of the Nurali massif.

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43

Anderson, H. Elizabeth, and Donald W. Davis. "U–Pb geochronology of the Moyie sills, Purcell Supergroup, southeastern British Columbia: implications for the Mesoproterozoic geological history of the Purcell (Belt) basin." Canadian Journal of Earth Sciences 32, no. 8 (1995): 1180–93. http://dx.doi.org/10.1139/e95-097.

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The Mesoproterozoic Purcell Supergroup (and its equivalent in the United States, the Belt Supergroup) is a thick sedimentary sequence formed in an extensional basin of uncertain age and tectonic setting. The voluminous tholeiitic Moyie sills intrude turbidites of the lower and middle Aldridge Formation, the lowest division of the Purcell Supergroup. Many of the sills were intruded into soft sediment and one intrudes the Sullivan sedimentary exhalative (SEDEX) orebody, so their age approximates that of the sediments and the Sullivan deposit. New U–Pb dates of zircon from four sills are older th

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44

Gao, Peng, Chris Yakymchuk, Jian Zhang, Changqing Yin, Jiahui Qian, and Yanguang Li. "Preferential dissolution of uranium-rich zircon can bias the hafnium isotope compositions of granites." Geology 50, no. 3 (2021): 336–40. http://dx.doi.org/10.1130/g49656.1.

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Abstract Hafnium (Hf) isotopes in zircon are important tracers of granite petrogenesis and continental crust evolution. However, zircon in granites generally shows large Hf isotope variations, and the reasons for this are debated. We applied U-Pb geochronology, trace-element, and Hf isotope analyses of zircon from the Miocene Himalayan granites to address this issue. Autocrystic zircon had εHf values (at 20 Ma) of–12.0 to–4.3 (median =–9). Inherited zircon yielded εHf values (at 20 Ma) of–34.8 to +0.3 (median =–13); the majority of εHf values were lower than those of autocrystic zircon. The εH

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45

Kylander-Clark, Andrew R. C. "Expanding the limits of laser-ablation U–Pb calcite geochronology." Geochronology 2, no. 2 (2020): 343–54. http://dx.doi.org/10.5194/gchron-2-343-2020.

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Abstract. U–Pb geochronology of calcite by laser-ablation inductively coupled plasma mass spectrometry (LA-ICPMS) is an emerging field with potential to solve a vast array of geologic problems. Because of low levels of U and Pb, measurement by more sensitive instruments, such as those with multiple collectors (MCs), is advantageous. However, whereas measurement of traditional geochronometers (e.g., zircon) by MC-ICPMS has been limited by detection of the daughter isotope, U–Pb dating of calcite can be limited by detection of the parent isotope if measured on a Faraday detector. The Nu P3D MC-I

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Wohlgemuth-Ueberwasser, Cora C., Jan A. Schuessler, Friedhelm von Blanckenburg, and Andreas Möller. "Matrix dependency of baddeleyite U–Pb geochronology by femtosecond-LA-ICP-MS and comparison with nanosecond-LA-ICP-MS." Journal of Analytical Atomic Spectrometry 33, no. 6 (2018): 967–74. http://dx.doi.org/10.1039/c7ja00403f.

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Ruiz-Cruz, M. D., and C. Sanz de Galdeano. "Genetic significance of zircon in orthogneisses from Sierra Nevada (Betic Cordillera, Spain)." Mineralogical Magazine 81, no. 1 (2017): 77–101. http://dx.doi.org/10.1180/minmag.2016.080.072.

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AbstractZircon from two types of orthogneisses (inheritance-rich and inheritance-poor) from Sierra Nevada (Betic Cordillera, Spain) was investigated by integrating U–Pb geochronology, cathodoluminescence and back-scattered SEM imaging, laser-ablation inductively coupled plasma mass spectrometry analyses and Raman spectroscopy to examine the conditions of magmatic zircon growth and the variable extent and mechanisms of the Alpine modifications. Zircon from inheritance-rich gneiss consists of two main domains: inherited (Neoproterozoic-to-Early Paleozoic and Devonian) cores and magmatic overgrow

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48

Zhang, Shao-Hua, Wei-Qiang Ji, Hao Zhang, et al. "Identification of Forearc Sediments in the Milin-Zedong Region and Their Constraints on Tectonomagmatic Evolution of the Gangdese Arc, Southern Tibet." Lithosphere 2020, no. 1 (2020): 1–20. http://dx.doi.org/10.2113/2020/8835259.

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Abstract The Xigaze forearc sediments revealed the part of the tectonomagmatic history of the Gangdese arc that the bedrocks did not record. However, the sediments’ development is restricted to the region around and west of Xigaze City. Whether the eastern segment of the arc had a corresponding forearc basin is yet to be resolved. In this study, a field-based stratigraphic study, detrital zircon U-Pb geochronology (15 samples), and Hf isotopic analyses (11 of the 15 samples) were carried out on four sections in the Milin-Zedong area, southeast Tibet. The analytical results revealed the existen

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Luo, Tao, Xiaodong Deng, Jianwei Li, et al. "U–Pb geochronology of wolframite by laser ablation inductively coupled plasma mass spectrometry." Journal of Analytical Atomic Spectrometry 34, no. 7 (2019): 1439–46. http://dx.doi.org/10.1039/c9ja00139e.

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MAPEO, R. B. M., R. A. ARMSTRONG, and A. B. KAMPUNZU. "SHRIMP U–Pb zircon geochronology of gneisses from the Gweta borehole, northeast Botswana: implications for the Palaeoproterozoic Magondi Belt in southern Africa." Geological Magazine 138, no. 3 (2001): 299–308. http://dx.doi.org/10.1017/s001675680100526x.

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This paper presents new U–Pb zircon analyses from garnet–sillimanite paragneisses from the Gweta borehole in northeast Botswana. Concordant to near-concordant analyses of zircon from these rocks reveal a billion year history from 3015 ± 21 Ma for the oldest detrital grain measured, to the age of high-grade metamorphism, 2027 ± 8 Ma. The maximum age of sedimentation in the Magondi belt is constrained by the age of the youngest concordant detrital zircon at 2125 ± 6 Ma. This contrasts with the age of sedimentation in the Central Zone of the Limpopo belt which is Archaean. The comparison of our r

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