Articoli di riviste: "U-Pb dating on zircons"

1

Huang, Yong-Shu, Qiu-Li Li, Yu Liu, Ping-Ping Liu, Sun-Lin Chung e Xian-Hua Li. "238U–206Pb dating of U-series disequilibrium zircons by secondary ion mass spectrometry". Journal of Analytical Atomic Spectrometry 36, n. 5 (2021): 999–1006. http://dx.doi.org/10.1039/d0ja00510j.

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Theoretical and analytical methods for ²³⁸U–²⁰⁶Pb dating of U-series disequilibrium zircons by secondary ion mass spectrometry are developed. U–Pb dates improve age precision 3 times better than U–Th dating for zircon >150 ka.

2

Ito, Hisatoshi. "Simultaneous U–Pb and U–Th Dating Using LA-ICP-MS for Young (<0.4 Ma) Minerals: A Reappraisal of the Double Dating Approach". Minerals 14, n. 4 (22 aprile 2024): 436. http://dx.doi.org/10.3390/min14040436.

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Simultaneous U–Pb and U–Th dating using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was performed on the ca. 0.1 Ma Toya tephra and the ca. 0.08 Ma SS14-28 U–Th zircon reference material. In U–Pb dating, both Th/U and Pa/U partitioning between magma and minerals were considered. In U–Th dating, both abundance sensitivity and molecular interferences on 230Th were reevaluated. As a result, the Toya tephra yielded an accurate weighted mean U–Pb age of 0.103 ± 0.029 Ma (2σ) using zircon and monazite. Conversely, the SS14-28 zircon yielded an inaccurate U–Pb age (0.25 ± 0.10 Ma), which was attributed to low 206Pb signal intensity. Both the Toya tephra zircon and the SS14-28 zircon yielded accurate U–Th model ages of 0.108 ± 0.014 Ma and 0.078 ± 0.007 Ma, respectively. The agreement of U–Pb and U–Th ages for Toya indicates that simultaneous U–Pb and U–Th dating is possible and viable. The inappropriate age of SS14-28 U–Pb age and appropriate U–Th model age also indicates it is preferable to apply both U–Pb and U–Th dating simultaneously for young (<0.4 Ma) zircons to check internal consistency. The proposed double dating approach may be especially useful for small grains when it otherwise would be impossible to obtain multiple ages from a single grain. By adopting simultaneous U–Pb and U–Th dating using LA-ICP-MS, zircon crystallization ages as old as 4.5 Ga to as young as 0.1 Ma (or even younger) can be obtained in a quick and cost-effective manner with a reasonable (~5% at 1σ) uncertainty.

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Huijsmans, Jasper R., Maartje Hamers, Martyn R. Drury e James K. W. Lee. "Recrystallisation and Trace-Element Mobility in Zircons: Implications for U-Pb Dating". Minerals 12, n. 12 (23 novembre 2022): 1489. http://dx.doi.org/10.3390/min12121489.

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Complex microstructures of zircon recrystallisation have been discovered in igneous and metamorphic zircons from the Jack Hills Metasedimentary Belt in Western Australia, and the granitic injection complex of Harris in north-west Scotland. Cathodoluminescence (CL), electron backscatter diffraction (EBSD) and wavelength dispersive spectroscopy (WDS) analysis reveal that recrystallisation in the studied zircons is often characterised by (1) translation, bending and fading of the oscillatory zoning; (2) structural recovery of the zircon; (3) an enrichment in Hf and depletion in Y in recrystallised zircon; and (4) the formation of a recrystallisation interface with a minor (<2°) misorientation. A new, composite recrystallisation model in which trace element and dislocation migration occurs shortly after crystallisation during magmatic cooling and pipe diffusion along dislocation arrays formed by the accumulation of dislocations allows enhanced diffusion to enrich Hf and leach U, Pb and Y. After the recrystallisation event, subsequent metamictization of primary zircon (typically with oscillatory zoning) creates zones that can structurally recover through a diffusion-reaction re-equilibration mechanism, resulting in further trace-element mobility. These mechanisms can create complex microstructures in zircons, suggesting that a detailed understanding of the crystallisation and recrystallisation history of a zircon may be required to accurately interpret its U-Pb ages.

4

Schiøtte, L., W. Compston e D. Bridgwater. "Ion probe U–Th–Pb zircon dating of polymetamorphic orthogneisses from northern Labrador, Canada". Canadian Journal of Earth Sciences 26, n. 8 (1 agosto 1989): 1533–56. http://dx.doi.org/10.1139/e89-131.

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Rounded zircons included within igneous zircons from the Uivak I gneisses, northern Labrador, have ages of up to 3863 ± 12 Ma (2σ), showing the (former) existence of rocks that predate the Uivak gneisses by more than 100 Ma. The igneous zircons themselves have experienced varying amounts of early Pb loss, but age estimates based on maximum 207Pb/206Pb from three separate gneiss samples agree to within error at 3732 ± 6 Ma (2σ), which is taken as the age of emplacement of the igneous precursor to the dominant component of the Uivak gneisses. A new generation of zircons was formed during migmatization at ca. 3620 Ma. The volumetrically less important Lister gneiss was emplaced at 3235 ± 8 Ma (2σ). In the late Archaean, different parts of the gneiss complex were subjected to different grades of metamorphic overprinting. The zircon chronology of gneisses affected by granulite facies metamorphism suggests a rapid sequence of events, with simultaneous recrystallization of old zircons and growth of new U-poor zircons at 2766 ± 17 Ma (2σ), followed by partial melting at 2744 ± 4 Ma (2σ), and further recrystallization and growth of U-poor zircons afterwards. No late Archaean zircon growth has been recorded from orthogneisses unaffected by granulite fades metamorphism.

5

Kohút, Milan, Pavel Uher, Marián Putiš, Martin Ondrejka, Sergey Sergeev, Alexander Larionov e Ilya Paderin. "SHRIMP U-Th-Pb zircon dating of the granitoid massifs in the Malé Karpaty Mountains (Western Carpathians): evidence of Meso-Hercynian successive S- to I-type granitic magmatism". Geologica Carpathica 60, n. 5 (1 ottobre 2009): 345–50. http://dx.doi.org/10.2478/v10096-009-0026-z.

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SHRIMP U-Th-Pb zircon dating of the granitoid massifs in the Malé Karpaty Mountains (Western Carpathians): evidence of Meso-Hercynian successive S- to I-type granitic magmatismRepresentative granitic rock samples from the Malé Karpaty Mountains of the Western Carpathians (Slovakia) were dated by the SHRIMP U-Th-Pb isotope method on zircons. Oscillatory zoned zircons revealed concordant Mississippian magmatic ages: 355±5 Ma in Bratislava granodiorite, and 347±4 Ma in Modra tonalite. The results document nearly synchronous, successive Meso-Hercynian plutonic events from S-type to I-type granites. The Neo-Proterozoic inherited zircon cores (590±13 Ma) were identified in the Bratislava S-type granitic rocks whereas scarce Paleo-Proterozoic inherited zircons (1984±36 Ma) were detected within the Modra I-type tonalites.

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Doughty, P. Ted, e K. R. Chamberlain. "Protolith age and timing of Precambrian magmatic and metamorphic events in the Priest River complex, northern Rockies". Canadian Journal of Earth Sciences 45, n. 1 (1 gennaio 2008): 99–116. http://dx.doi.org/10.1139/e07-067.

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U–Pb dating of detrital zircons, magmatic zircons, and metamorphic zircon overgrowths and titanites from the Priest River complex, USA, reveal the ages of high-grade metasedimentary rocks, intrusive ages of associated igneous rocks, and the timing of Precambrian metamorphic events. Sensitive high-mass resolution ion microprobe (SHRIMP) U–Pb dates of detrital zircons from the Hauser Lake gneiss and Gold Cup Quartzite are predominately Paleoproterozoic with some Archean grains. The Hauser Lake gneiss contains detrital zircons with nearly concordant ages as young as 1511 Ma. Isotope dilution – thermal ionization mass spectrometry (ID–TIMS) and chemical abrasion – thermal ionization mass spectrometry (CA–TIMS) dating of magmatic zircon from amphibolites in the Hauser Lake Gneiss yield 1470–1430 Ma crystallization ages based on discordant data, with Cretaceous lower intercepts. The U–Pb zircon systematics are very complex and reflect multiple periods of magmatic and metamorphic growth. A combination of mechanical abrasion, chemical abrasion (CA–TIMS), and SHRIMP methods were required to identify the major geochronological components. These data, in addition to one Nd model age, strengthen correlations between the Hauser Lake Gneiss and the lower Belt–Purcell Supergroup and the Gold Cup Quartzite with the Neihart Quartzite, which underlies the Belt–Purcell Supergroup. Four SHRIMP-dated metamorphic zircon overgrowths give concordant Grenville dates with a weighted average of 1127 ± 110 Ma. This Grenville-aged metamorphic event is recorded by many isotopic systems in the Belt–Purcell basin and reflects a static thermal event, possibly driven by magmatism at depth.

7

Smirnova, Yu N., A. V. Kurilenko, V. B. Khubanov e С. И. Дриль. "Composition and Age of Sources of the Lower–Middle Cambrian (?) Terrigenous Rocks from The Ernichny Formation in the Argun Massif, Eastern Part of the Central Asian Fold Belt". Стратиграфия 31, n. 5 (1 settembre 2023): 98–115. http://dx.doi.org/10.31857/s0869592x23050071.

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The paper presents the results of the mineralogical and geochemical studies of sandstones and siltstones of the Ernichny formation of the Argun series in the Argun continental massif, and the results of U–Pb (LA‑ICP-MS) dating for the detrital zircons from these rocks. It is established that the youngest detrital zircons from sandstone of the Ernichny Formation have age of 549–570 Ma. A maximum on the relative probability curve of zircon age corresponds to 566 Ma. These data determine the lower age limit of their accumulation on the border of the Ediacaran and Paleozoic age. According to the results of U–Pb dating of detrital zircon, the majority of detrital zircons from sandstones of Ernichny Formation are characterized by Neo- and Paleoproterozoic ages. The sources of zircons were Neo- and Paleoproterozoic igneous and metamorphic rocks that were widely developed within the Argun continental massif. In turn, the geochemical features of the terrigenous rocks of the Ernichny Formation, together with the presence of the poorly sorted and rounded clastic material in the studied samples, as well as the presence of interlayers of gravelstones, enabled us to establish that they were formed in a subduction-related setting.

8

Greenough, John D., Tom E. Krogh, Sandra L. Kamo, J. Victor Owen e Alan Ruffman. "Precise U-Pb dating of Meguma basement xenoliths: new evidence for Avalonian underthrusting". Canadian Journal of Earth Sciences 36, n. 1 (20 gennaio 1999): 15–22. http://dx.doi.org/10.1139/e98-079.

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U-Pb zircon and monazite dates for granulite-facies basement xenoliths from the Popes Harbour dyke on the eastern shore of Nova Scotia provide strong evidence that the Meguma terrane overlies Avalonian basement. Slightly discordant (1.6%), "facetted" zircons from a mafic granulite indicate a minimum crystallization age of ~629 Ma, with near-concordant (0.7%) rounded zircons suggesting a maximum age for the last metamorphic event affecting the zircons at ~575 Ma. Two near-concordant (-0.9 to 0.4%) monazite fractions from a pelitic granulite indicate a major metamorphic disturbance at 378 ± 1 Ma, ~10 Ma prior to dyke entrainment and coincident with Meguma regional metamorphism. Projections from 378 Ma through four highly discordant (15-42%) metapelite zircon fractions give provenance ages between 880 and 1050 Ma and two others project to maximum ages of ~1530 Ma. Unlike Meguma sediments which lack Grenvillian-age (~1 Ga) detrital zircons and are dominated by ~2000 Ma detrital zircons, these dates indicate a dominantly Grenvillian-age provenance for the pelitic xenoliths. The "Avalonian" igneous, metamorphic, and provenance ages from the xenoliths suggest the Meguma rests on Avalonian basement. Because Avalonian sediments need a Grenvillian provenance and Meguma sediments lack such a source but require a [Formula: see text]2.0 Ga component missing in the xenoliths, it seems unlikely the Meguma was deposited on Avalonian crust. Thus the dating places on firmer footing the suggestion from earlier structural, seismic, and geochemical work that the Meguma structurally overlies Avalonian terrane. Thrusting occurred between the time of earliest Meguma deformation (~400 Ma) and intrusion of the xenolith-bearing dyke (~370 Ma).

9

Zhang, Zhenkai, Tengfei Zhou, Dongtao Li, Hua Wang, Biao Du, Duanchang Zhao, Yafeng Zhang et al. "Geochemistry, Detrital Zircon U-Pb Geochronology, and Lu-Hf Isotopes of the Metasedimentary Rocks (Xinghongpu Formation, Late Devonian) in the Central South Qinling Orogenic Belt: Implications for Provenance and Tectonics". Minerals 13, n. 6 (2 giugno 2023): 768. http://dx.doi.org/10.3390/min13060768.

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The Xinghongpu Formation is very important for understanding the Devonian tectonic evolution of the South Qinling orogenic belt. Geochemical, detrital zircon U-Pb-Hf isotopic studies were carried out on the Late Devonian metasedimentary rocks of the Xinghongpu Formation to constrain the depositional age, the provenance, and the tectonic setting. The detrital zircon U-Pb dating results revealed that the depositional age of the Xinghongpu Formation of the Late Devonian was not earlier than 363.2 Ma. The whole-rock geochemistry suggested that (1) this suite of metasedimentary rocks was mainly derived from quartzose sediments of mature continental provenance, with a small contribution from mafic and intermediate igneous provenance, and (2) the metasedimentary sandstone of the Xinghongpu Formation from the Late Devonian was deposited in an active continental margin to continental arc setting. The detailed detrital zircon U-Pb dating showed that the age spectra of detrital zircon could be divided into four groups: (1) 416–480 Ma, accounting for about 23%; (2) 740–850 Ma, accounting for about 19%; (3) 889–1017 Ma, accounting for about 19%; and (4) 1072–1146 Ma, accounting for about 12%. It also contained a group of Early Proterozoic zircons. The age and Hf isotope of the detrital zircons suggested that the clastic sediment deposited in the Xinghongpu Formation mainly came from the South Qinling Orogenic Belt and the North Qinling Orogenic Belt. The detrital zircon Lu-Hf isotopes indicated that most zircons were the products of the ancient crustal remelting, and the mantle-derived magmatic sources contributed to the provenance. The Xinghongpu Fm. formed in an oceanic basin in a continental margin environment with arc systems.

10

Xie, Lie-Wen, Jin-Hui Yang, Qing-Zhu Yin, Yue-Heng Yang, Jing-Bo Liu e 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, n. 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 ²⁰⁶Pb/²³⁸U 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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Schiøtte, L., W. Compston e D. Bridgwater. "U–Th–Pb ages of single zircons in Archaean supracrustals from Nain Province, Labrador, Canada". Canadian Journal of Earth Sciences 26, n. 12 (1 dicembre 1989): 2636–44. http://dx.doi.org/10.1139/e89-224.

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Ion-probe U–Pb dating of igneous zircons from an acid metavolcanite belonging to the Nulliak supracrustal association of the Saglek area, northern Labrador, suggests an original age of 3776 ± 8 Ma (2σ), interpreted as the deposition age of the volcanite. In accordance with the field model, this is slightly but significantly older than the previously obtained ion-probe U–Pb age of igneous zircons from the main phase of the Uivak gneisses, which carries inclusions of the supracrustal association. A secondary event of zircon growth recorded in the metavolcanite has a maximum age of 3065 ± 8 Ma (2σ).A metapelite belonging to the Weekes amphibolite supracrustal association of the Hopedale area south of Nain contains rounded, low-U zircons of 3258 ± 24 Ma (2σ) age. Occasional textural evidence suggests that some of these zircons are most likely detrital grains of igneous origin, in which case 3258 ± 24 Ma is a minimum age of the source from which the sediment was derived and a maximum age for the deposition of the sediment. However, the possibility that the age represents recrystallization of the sediment under high-grade conditions cannot be ruled out. A 2841 ± 5 Ma (2σ) age obtained on a younger generation of euhedrally zoned high-U zircons from the metapelite is within error of the published bulk zircon U–Pb age of the tonalitic component of the Kanairiktok plutonic suite that intrudes the older orthogneiss and supracrustal units in the area. These younger zircons are most likely to have grown during migmatization of the metasediment at the time of emplacement of the suite.The zircon data give no positive evidence to support correlation between the Nulliak supracrustals and the Weekes amphibolite association.

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Dusel-Bacon, Cynthia, e Ian S. Williams. "Evidence for prolonged mid-Paleozoic plutonism and ages of crustal sources in east-central Alaska from SHRIMP U–Pb dating of syn-magmatic, inherited, and detrital zircon". Canadian Journal of Earth Sciences 46, n. 1 (gennaio 2009): 21–39. http://dx.doi.org/10.1139/e09-005.

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Sensitive high-resolution ion microprobe (SHRIMP) U–Pb analyses of igneous zircons from the Lake George assemblage in the eastern Yukon–Tanana Upland (Tanacross quadrangle) indicate both Late Devonian (∼370 Ma) and Early Mississippian (∼350 Ma) magmatic pulses. The zircons occur in four textural variants of granitic orthogneiss from a large area of muscovite–biotite augen gneiss. Granitic orthogneiss from the nearby Fiftymile batholith, which straddles the Alaska–Yukon border, yielded a similar range in zircon U–Pb ages, suggesting that both the Fiftymile batholith and the Tanacross orthogneiss body consist of multiple intrusions. We interpret the overall tectonic setting for the Late Devonian and Early Mississippian magmatism as an extending continental margin (broad back-arc region) inboard of a northeast-dipping (present coordinates) subduction zone. New SHRIMP U–Pb ages of inherited zircon cores in the Tanacross orthogneisses and of detrital zircons from quartzite from the Jarvis belt in the Alaska Range (Mount Hayes quadrangle) include major 2.0–1.7 Ga clusters and lesser 2.7–2.3 Ga clusters, with subordinate 3.2, 1.4, and 1.1 Ga clusters in some orthogneiss samples. For the most part, these inherited and core U–Pb ages match those of basement provinces of the western Canadian Shield and indicate widespread potential sources within western Laurentia for most grain populations; these ages also match the detrital zircon reference for the northern North American miogeocline and support a correlation between the two areas.

13

Takehara, Lucy, Farid Chemale Júnior, Léo A. Hartmann, Ivo A. Dussin e Koji Kawashita. "U-Pb dating by zircon dissolution method using chemical abrasion". Anais da Academia Brasileira de Ciências 84, n. 2 (giugno 2012): 399–405. http://dx.doi.org/10.1590/s0001-37652012000200011.

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Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-MultiCollector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3±4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using 235U-205Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7±1.8 Ma (error 0.43 %) based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I â€“ 416.75±1.3 Ma; Temora II â€“ 416.78±0.33 Ma) and established as 416±0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error < 1 %), mainly for high resolution stratigraphic studies of Phanerozoic sequences.

14

Li, Liming, Fanyan Yang, Mingtao Li, Zhirong Liang, Xuedong Ma e Jingxiong Tian. "U–Pb zircon dating of the Paleoproterozoic khondalite series in the northeastern Helanshan region and its geological significance". Open Geosciences 14, n. 1 (1 gennaio 2022): 544–67. http://dx.doi.org/10.1515/geo-2022-0380.

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Abstract Petrography, zircon cathodoluminescence, and laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) U–Pb zircon dating were performed on the Paleoproterozoic khondalite series and the intrusive altered diabase dykes developed in the northeastern Helanshan region were analyzed. The results showed that most of the zircons in the khondalite series were detrital zircons with oscillatory zoning and a high Th/U ratio, with few metamorphic zircons having a low Th/U ratio. The 207Pb/206Pb age of the detrital zircons ranged from 3131–1980 Ma, which constrained the protolith age of the Helanshan khondalite series to after 1980 Ma. The age of the metamorphic zircons indicated two age groups as follows: 1965–1921 Ma and 1876–1820 Ma. Besides, the age of altered diabase dykes was 1865–1850 Ma. In combination with previous studies, these new metamorphic ages indicated that the metamorphic events in the northeastern Helanshan region involved the collision followed by post-collisional extension and exhumation between the Yinshan Block to the north and the Ordos Block to the south. Moreover, the 1965–1921 Ma group represented the period of the collision between the Yinshan Block and the Ordos Block and the subsequent post-collisional extension event, whereas 1876–1820 Ma indicated the period of the exhumation stage.

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Krasnobaev, A. A., P. M. Valizer, E. V. Medvedeva, A. B. Nemov e A. L. Perchuk. "U-Pb age and metamorphism of rocks of Voshnevogorsky sequence (South Ural)". Moscow University Bulletin. Series 4. Geology, n. 2 (28 aprile 2020): 51–62. http://dx.doi.org/10.33623/0579-9406-2020-2-51-62.

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In the article present results of U-Pb — dating of zircons and petrologic-geochemical study of garnet-biotite plagiogneises and quartz-plagioclase-amphibole granofels host rocks samples from Vishnevogorsky sequence of the oldest rocks of the southern Urals Eastern domain are presented. U-Pb-dating of zircons were obtained by ion microprobe (SHRIMP II). The maximum age of the substrate plagiogneises Vishnevogorsky sequence not younger than 2700 Ma, and granulitic metamorphism plagiogneises falls on the Proterozoic age range 1740–2220 Ma. The dates obtained for plagiogneises and granofels Vishnevogorsky sequence reflect all major (PR1–P1) age stages of the Urals development. Many of the dated events are manifested only in the zircons generation and are not reflected in the mineral paragenesises of the studied rocks.

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Shi, Yu, Xi Jun Liu e Zuo Hai Feng. "Formation Age of the Qinling Complex and the early Paleozoic Tectonic Event". Advanced Materials Research 734-737 (agosto 2013): 60–70. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.60.

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The Qinling orogenic belt (QOB) located between the North China Craton (NCC) and the South China Craton (SCC) is composed of the Northern Qinling Belt (NQB) and the Southern Qinling Belt (SQB). This study presents new geochemical data, zircon U-Pb ages and Hf isotopes from two rocks from the Qinling complex in the NQB. LA-ICP-MS zircon U-Pb dating results suggest that the Qinling complex was formed in early Neoproterozoic and experienced the early Paleozoic metamorphism. HighεHf(t) values of 9.0-12.0 for the early Paleozoic zircons indicated that there is mantle-derived magma intruding into the Qinling complex in the early Paleozoic.

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Zaccaria, Daria, Noemi Vicentini, Maria Grazia Perna, Gianluigi Rosatelli, Victor V. Sharygin, Emma Humphreys-Williams, Will Brownscombe e Francesco Stoppa. "Lamprophyre as the Source of Zircon in the Veneto Region, Italy". Minerals 11, n. 10 (30 settembre 2021): 1081. http://dx.doi.org/10.3390/min11101081.

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Discrete zircons, up to 9 mm in length, occur in alluvial deposits from the Veneto area. They are likely derived from the disaggregation of lamprophyric rocks belonging to a regional, pervasive dyke-swarm. Zircon and REE phases occur in both alkaline lamprophyres and connate calcite-bearing felsic lithics and their debris in lamprophyre breccia. We present 36 new complete U–Pb and trace element analyses of zircons and associated inclusions. We used a statistical approach on a larger dataset using new and literature data to evaluate the confidence figure to give an estimation of age of zircons. Inclusions suggest a genetic link with an S–CO2–ZrO–BaO–SrO–CaO-rich fluid/melt possibly associated with carbonate-rich alkaline parental magma and a metasomatised mantle source. This paper confirms the importance of calcite–syenite and lamprophyre genetic link and zircon magmatic origin, in contrast with hydrothermal and metamorphic zircons. U–Pb dating by LA-ICP-MS provides time constrains (40.5–48.4 Ma, Lutetian), consistent with the age of the alkaline magmatic event. Trace element data indicate a link to anorogenic magmatism associated with mantle upwelling. Complex zoning is highlighted by cathodoluminescence images. The Veneto zircons are helpful for regional geological information and may have commercial potential as a critical resource for green technologies.

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Liu, Chao, Xiangdong Chang, Beilei Sun e Fangui Zeng. "New Insight into the Depositional Age of No. 6 Coal in Heidaigou Mine, Late Paleozoic Jungar Coalfield, Inner Mongolia, China". Sustainability 14, n. 10 (21 maggio 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. 6 coal seam had strongly positive Ce (Ce/Ce* = 2.4–224.6) and strongly negative Eu anomalies (Eu/Eu* = 0.1–0.6). Combined with the clear oscillatory zones in the cathodoluminescence images, all the zircon grains of the No. 6 coal were characteristic of zircons with magmatic origins. The 206Pb/238U ages of 34 zircon grains produced a narrow age population of 303–286 Ma, with a weighted average age of 293.0 ± 1.5 Ma (mean-squared weighted deviation = 1.5). Therefore, we infer that the No. 6 coal in the Heidaigou Mine was deposited during the Early Permian, and the Carboniferous–Permian boundary should be located stratigraphically lower than the No. 6 coal. The zircon U–Pb geochronology is a useful tool to determine the depositional ages of non-marine-influenced coal.

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Mortensen, J. K., J. R. Montgomery e J. Fillipone. "U–Pb zircon, monazite, and sphene ages for granitic orthogneiss of the Barkerville terrane, east-central British Columbia". Canadian Journal of Earth Sciences 24, n. 6 (1 giugno 1987): 1261–66. http://dx.doi.org/10.1139/e87-120.

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Granitic orthogneiss forms an important component of the Barkerville terrane of southeastern British Columbia. Rb–Sr whole-rock ages for the orthogneisses are ambiguous and range from Late Proterozoic to mid-Paleozoic, with large associated errors. U–Pb dating of zircon, monazite, and sphene has been employed in an attempt to establish precise crystallization ages for two of the orthogneiss bodies. U–Pb systematics for zircons from both bodies show the combined effects of inheritance of zircon cores and postcrystallization Pb loss. This complexity precludes a precise estimate of the age of emplacement of the granitic protoliths of the gneiss. The data do, however, constrain possible emplacement ages for the bodies to between 335 and 375 Ma (Late Devonian – mid-Mississippian).A U–Pb age of 174 ± 4 Ma for metamorphic sphene from one of the orthogneiss bodies is interpreted as dating the end of the second phase of deformation in the area. Two nearly concordant U–Pb ages of 114 and 117 Ma for monazite from the second body remain problematical. These data suggest either that the monazite grew during a relatively young shearing and (or) metamorphic event that locally affected the Barkerville terrane or that the closure temperatue for the U–Pb system in monazite is lower than had previously been inferred, or both.

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Kanygina, N. A., A. A. Tretyakov, K. E. Degtyarev, K. N. Pang, K. L. Van, H. Y. Lee e J. V. Plotkina. "First results of dating detrital zircons from the late precambrian quartzite-schist sequences of Chu block (Southern Kazakhstan)". Доклады Академии наук 489, n. 1 (10 novembre 2019): 57–61. http://dx.doi.org/10.31857/s0869-5652489157-61.

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U-Pb geochronological studies of detrital zircons from quartzite-schist sequences of the Akbastau Formations of the Chu block (northwest of the Chu-Kendyktas terrane, Southern Kazakhstan) have been provided. The concordant ages of detrital zircons are predominantly within the intervals of 1672-2115 Ma with peaks at 1697, 1780, 1857 and 2066 Ma. Individual zircon grains display ages of 2291-2332 Ma with peaks at 2303 and 2322 Ma. Neoarchean ages 2608-2747 with peak at 2681 Ma characterize another significant zircon population. The lower limit of deposition for the Akbastau Formations of the Chu block, corresponding to the youngest statistically significant zircon population, is estimated at 1,7 billion years.

21

WANG, JIALIN, CHAODONG WU, ZHUANG LI, WEN ZHU, TIANQI ZHOU, JUN WU e JUN WANG. "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, n. 5 (16 gennaio 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 12 sandstones exhibited similar zircon U–Pb age distribution patterns with major age groups at 360–320 Ma and 320–300 Ma, and with some grains giving ages of > 541 Ma, 541–360 Ma, 300–250 Ma and 250–200 Ma. Coupled with the compiled palaeocurrent data, the predominant sources were the Late Carboniferous volcanic rocks of the North Tianshan and Palaeozoic magmatic rocks of the Yili–Central Tianshan. There was also input from the Bogda Mountains in Middle–Late Triassic time. The comprehensive geological evidence indicates that the Upper Carboniferous – Lower Permian strata were probably deposited in an extensional context which was related to a rift or post-collision rather than arc-related setting. Conspicuously, the large range of U–Pb ages of the detrital zircons, increased sedimentary lithic fragments, fluvial deposits and contemporaneous Triassic zircon ages argue for a Middle–Late Triassic orogenic movement, which was considered to be the initial uplift of the Bogda Mountains.

22

Reiners, P. W. "(U-Th)/(He-Pb) double dating of detrital zircons". American Journal of Science 305, n. 4 (1 aprile 2005): 259–311. http://dx.doi.org/10.2475/ajs.305.4.259.

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23

Prytchin, M. E., E. I. Soroka e V. N. Puchkov. "Novel U-Pb isotopic zircon data on the rhyolite of the Saf’yanovskoe Cu-Zn deposit (Middle Urals)". LITHOSPHERE (Russia) 21, n. 6 (29 dicembre 2021): 884–93. http://dx.doi.org/10.24930/1681-9004-2021-21-6-884-893.

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Research subject. Zircons from the Saf’yanovskoe Cu-Zn deposit rhyolite (Middle Urals). For the first time, zircon U-Pb dating for the rhyolite of the ore-bearing volcanic-sedimentary rocks of the Saf’yanovskoe deposit was performed. The volcanites are characterized by an andesite-rhyodacite composition and are localized at the southern edge of the Rezhevskaya structural-formation zone (SFZ) of the Eastern Ural megazone. A number of publications assign these rocks either to the basalt-rhyolite formation of the Middle Devonian, or to the basalt-andesite-dacite-rhyolite formation of the Lower-Middle Devonian.Aim. To estimate the age of the ore-bearing volcanic rocks under study using the U-Pb SHRIMP-II isotop ic system of zircon from the rhyolite of the eastern side of the Saf’yanovskoe deposit. By its chemical composition, the rhyolite belongs to the silicic varieties of subvolcanic rocks. Methods and results. The U-Pb isotopic system of zircon was studied by 5-collector mass-spectrometer of high precision and emission of the secondary ions SHRIMP-II (ASI, Australia) in the VSЕGEI Institute. U-Pb relations were investigated by a procedure developed by I.S. Williams. The U-Pb data obtained based on 13 zircon grains showed the age of 422.8 ± 3.7 Ma. Conclusions. The U-Pb dating of zircon obtained previously from the lens-shaped andesite bodies of the western side of the Safyanovskoe deposit gave the age of 422.8 Ma, which corresponds to the Przydoli series epoch of the Upper Silurian. We established that, among the volcanic rocks of the Saf’yanovskoe deposit, the effusive formations of the Upper Silurian are present.

24

Young, David N., e Lance P. Black. "U-Pb zircon dating of Proterozoic igneous charnockites from the Mawson Coast, East Antarctica". Antarctic Science 3, n. 2 (giugno 1991): 205–16. http://dx.doi.org/10.1017/s095410209100024x.

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We report ion-microprobe U-Pb zircon ages from charnockites of a large Proterozoic composite batholith, Mawson Coast, Australian Antarctic Territory. The charnockites crystallized from orogenic magmas of intermediate composition (mainly 54–68% SiO2) intruded into a granulite-facies metasedimentary gneiss sequence between the second and third recognized deformations. A sample of low-Ti charnockite provides an age of 954 ± 12 Ma and a high-Ti charnockite is dated at 985 ± 29 Ma (all ages quoted at 95% confidence). The age difference is not significant at the 95% confidence level. Both these ages were obtained from zircons with igneous zoning and/or morphology and thus are thought to date igneous crystallization. Zircons from a felsic gneiss xenolith within the charnockite have cores of various ages, many from 1.7 to 2.0 Ga, but with other grains between 1.0 and 1.5 Ga and a single 2.5 Ga zircon. These zircon cores are direct evidence for an early to middle Proterozoic age for the supracrustal basement sequence in this mobile belt. Many of these zircon cores are concordant but abundant discordant grains suggest a complex history of multiple Pb-loss events. Zircon rims grew at 921 ± 19 Ma, probably during the post-charnockite deformation (D3). Previously obtained Rb-Sr dates for charnockite of 886 ± 48 Ma and 910 ± 18 Ma were probably also rest during D3. A Rb-Sr isochron date of 1061 ± 36 Ma previously reported for high-Ti charnockite from Mawson Rock is thought to be erroneous, and a new date of 959 ± 58 Ma (consistent with both the igneous and reset dates above) is interpreted from those data.

25

Tevelev, A. V., A. A. Borisenko, I. D. Sobolev, A. Yu Kazansky, N. V. Pravikova, E. V. Kopte, E. A. Volodina e V. S. Chervyakovskiy. "The areas of manifestation of the Intravisean orogeny in the Eastern Zones of the Southern Urals (According to the detrital zircons U-Pb dating data from the Solnechnaya Formation of the Upper Visean)". Moscow University Bulletin. Series 4. Geology, n. 5 (17 dicembre 2022): 47–56. http://dx.doi.org/10.33623/0579-9406-2022-5-47-56.

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The aim of this work is to determine the provenance for the Upper Visean Solnechnay formation (The Southern Urals) using the U-Pb dating of detrital zircons. 138 zircon grains with discordance range of ± 10% were selected for the analysis. The vast majority of the zircons yielded the Ordovician and Cambrian ages. The main peak corresponds to the beginning of the Ordovician period (circa 480 Ma), and the secondary peaks correspond to the beginning of the Late Ordovician, the middle Cambrian, and the early Cambrian. The clastic material was derived from the East Ural megazone exclusively.

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Thompson, Jay M., Sebastien Meffre e Leonid Danyushevsky. "Impact of air, laser pulse width and fluence on U–Pb dating of zircons by LA-ICPMS". Journal of Analytical Atomic Spectrometry 33, n. 2 (2018): 221–30. http://dx.doi.org/10.1039/c7ja00357a.

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27

Krasnobaev, A. A., P. M. Valizer e 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, n. 1 (28 febbraio 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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Shumlyanskyy, L. V., M. Hofmann, B. V. Borodynya e G. V. Artemenko. "THE LOCAL SOURCES OF DETRITAL MATERIAL IN MIDDLE DEVONIAN QUARTZITES OF THE DONETS BASIN: RESULTS OF U-Pb LA-ICP-MS ZIRCON DATING". Mineralogical Journal 43, n. 3 (2021): 85–90. http://dx.doi.org/10.15407/mineraljournal.43.03.085.

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Results of U-Pb dating of zircons from the Middle Devonian sandstones of the Mykolaivka Suite, taken from the junction zone between the Azov Domain of the Ukrainian Shield and Donets basin, are reported. The rocks are taken from a drill core and they occur beneath a 210 m sequence of mafic and ultramafic volcanic rocks that belong to the Antonivka (D2-3) and Mykolaivka (D2) suites. In total, 28 U-Pb isotope analyses were performed. The predominant population (18 grains) of zircons yielded a concordant age of 2075±9 Ma (MSWD = 0.64). The second largest population consists of zircon crystals with concordant to nearly concordant ages ranging from 3130 to 2830 Ma. These results indicate a local origin for the detrital zircons. The occurrence of coarse-grained terrigenous sediments, derived from local rock sources, indicates significant erosion of the Precambrian basement that might have been caused by differential vertical movements during the Middle Devonian period. In the Donets basin, rifting and uplift started ca. 10 Myr before that of other parts of the Prypyat-Dnieper-Donets Paleorift.

29

Korovin, D., e V. Smirnov. "The first U-Pb (SHRIMP-II) dating of the reftinsky massif granitoids (eastern zone of the Middle Urals)". Proceedings of the Komi Science Centre of the Ural Division of the Russian Academy of Sciences, n. 2 (18 luglio 2023): 5–14. http://dx.doi.org/10.19110/1994-5655-2023-2-5-14.

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The article presents the results of U-Pb dating (SHRIMP-II, the Center for Isotope Research of the A.P. Karpinsky Russian Geological Research Institute) of zircon grains from leucogranite dating back to the final formation stage of the Reftinsky gabbro-granitoid massif, which is one of the largest magmatism areas of this type in the Urals. The intrusive formations of the dated magmatism episode form a sub-meridionally elongated chain of small (up to 5 km in diameter) bodies, which intrude the Silurian plagioclase granitoids building up the main part of the massif. These bodies are dominated by granodiorites, granites, and leucogranites with some gabbro, gabbronorites, diorites, and quartz diorites. By the chemical composition, the study rocks belong mainly to the moderate-potassium calc-alkaline series. The silica-rich petrographic rock varieties have a high-potassium composition. The concordant age of zircons from leucogranites is 396 ± 3 Ma. So, the formation of zircons falls in the same time interval with a significant episode of endogenous activity, i.e. the existence of the Devonian island arc within the Middle Urals (from the second half of the Emsian through the beginning of the Frasnian).

30

Jiang, Ziwen, Jinglan Luo, Xinshe Liu, Xinyou Hu, Shangwei Ma, Yundong Hou, Liyong Fan e Yuhua Hu. "Provenance and Implication of Carboniferous–Permian Detrital Zircons from the Upper Paleozoic, Southern Ordos Basin, China: Evidence from U-Pb Geochronology and Hf Isotopes". Minerals 10, n. 3 (15 marzo 2020): 265. http://dx.doi.org/10.3390/min10030265.

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Carboniferous–Permian detrital zircons are recognized in the Upper Paleozoic of the whole Ordos Basin. Previous studies revealed that these Carboniferous–Permian zircons occurred in the Northern Ordos Basin mainly originated from the Yinshan Block. What has not been well documented until now is where this period’s zircons in the Southern Ordos Basin came from, and very little discussion about their provenance. To identify the provenance of the detrital zircons dating from ~350 to 260 Ma, five sandstone samples from the Shan 1 Member of Shanxi Formation and eight sandstone samples from the He 8 Member of Shihezi Formation were analyzed for detrital zircon U-Pb age dating and in situ Lu-Hf isotopic compositions. The results indicate that the two age clusters of 520–378 Ma and ~350–260 Ma in the Southern Ordos Basin most likely derived from the North Qinling Orogenic Belt–North Qilian Orogenic Belt and the North Qinling Orogenic Belt, respectively. Furthermore, we propose that the zircons aging ~320–260 Ma are representative of the important tectonothermal events occurred in the North Qinling Orogenic Belt during the Late Paleozoic.

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Guzev, V. E., A. V. Terekhov, S. G. Skublov, V. I. Leontiev e A. V. Molchanov. "THE FIRST DATA ON THE U-PB AGE AND COMPOSITION OF ZIRCONS FROM ORE-BEARING SYENITES OF GORA RUDNAYA (SOUTH YAKUTIA)". Tikhookeanskaya Geologiya 40, n. 6 (2021): 85–99. http://dx.doi.org/10.30911/0207-4028-2021-40-6-85-99.

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The isotope-geochemical study (SHRIMP-II, SIMS) of zircons from syenites of Gora Rudnaya (South Yakutia) was carried out. Gora Rudnaya is a syenite massif in the form of a laccolith. It is located within the Central Aldan ore district and includes the recently discovered Morozkinskoye gold deposit. Vein and vein-disseminated gold mineralization occurs in low-temperature acid metasomatites – beresites (Qz-Ser-Ank-Py). Mineralization is restricted to steeply dipping submeridional crush zones within the intrusion. According to the zircon dating data, the age of ore-bearing syenites is about 130 Ma. The obtained age corresponds to the main stage of magmatism and the associated hydrothermal-metasomatic activity within the Central Aldan ore district. Two groups of zircons have been distinguished in syenites. The first group is characterized by features of magmatic genesis. For the second group of zircons, there is evidence of the influence of fluids on zircons: increased content of U, Th, and some non-formula elements (LREE, Ca, Ti, Sr). The presence of two varieties of zircons that are contrasting in composition and appearance, but of the same age, indicates that the magmatic crystallization of syenites from Gora Rudnaya and their fluid processing occurred simultaneously.

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Akinin, V. V., L. B. Golovneva e S. V. Shchepetov. "Isotopic age of flora-bearing beds from the Amka Formation stratotype, Okhotsk-Chukotka volcanic belt". Palaeobotany 7 (2016): 38–46. http://dx.doi.org/10.31111/palaeobotany/2016.7.38.

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U-Pb SHRIMP-dating of zircons from flora-bearing volcanic rocks of the Amka Formation stratotype (Ul'ya depression, Okhotsk-Chukotka volcanic belt) yield weighted mean 206Pb/238U age of 85.5 ±2 Ma (Santonian to Coniacian stage). This isotope dating is consistent with inferred Coniacian age of Ul’ya flora from the Amka Formation.

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Vetrova, N. I., E. V. Vetrov e E. F. Letnikova. "СHEMOSTRATIGRAPHY OF THE CARBONATE DEPOSITS OF THE KINTEREP FORMATION IN NORTHWESTERN SALAIR: FIRST DATA". Geology and mineral resources of Siberia, n. 2 (giugno 2022): 10–23. http://dx.doi.org/10.20403/2078-0575-2022-2-10-23.

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The results of geochemical, isotope-geochemical (Sr, C, O) surveys of the Kinterep Formation carbonate deposits of Northwestern Salair and U-Pb dating (LA-ICP-MS) of zircons were given. Carbonate rocks represented by pure limestones are characterized by normal values of δ18OSMOW from 19.8 to 23.8 ‰ and δ13 CPDB from –0.7 to +0.9, the isotopic composition of Sr (87Sr/86Sr ratio) varies in a narrow range from 0.708486 to 0.708582.Using Sr and C isotope chemostratigraphy and U-Pb dating of zircons, age limits (525-510 Ma) were determined for the formation time of carbonate deposits of the Kinterep Formation. The first data of isotope chemostratigraphy in combination with the results of geochronological studies made it possible to compare the limestones of the Kinterep Formation of Northwestern Salair with carbonate sections of Siberia and Central Asia.

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Leeman, William P., Jeffrey D. Vervoort e S. Andrew DuFrane. "U-Pb LA-ICP-MS Zircon Dating of Crustal Xenoliths: Evidence of the Archean Lithosphere Beneath the Snake River Plain". Minerals 14, n. 6 (30 maggio 2024): 578. http://dx.doi.org/10.3390/min14060578.

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New U-Pb zircon ages are reported for granulite facies crustal xenoliths brought to the surface by mafic lavas in the Snake River Plain. All samples yield Meso-to-Neoarchean ages (2.4–3.6 Ga) that significantly expand the known extent of the Archean Wyoming Craton at least as far west as the west-central Snake River Plain. Most zircon populations indicate multiple growth episodes with complexity increasing eastward, but they bear no record of major Phanerozoic magmatic episodes in the region. To extrapolate this work further west to the inferred craton boundary, zircons from southwestern Idaho batholith granodiorites were also analyzed. Although most batholith zircons record Cretaceous formation ages, all samples have zircons with inherited cores—with some recording Proterozoic ages (approaching 2 Ga). These data enhance our perspectives regarding lithosphere architecture beneath southern Idaho and adjacent areas and its possible influence on Cenozoic magmatism associated with the Snake River Plain–Yellowstone “melting anomaly”.

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KRISTOFFERSEN, MAGNUS, TOM ANDERSEN e ARILD ANDRESEN. "U–Pb age and Lu–Hf signatures of detrital zircon from Palaeozoic sandstones in the Oslo Rift, Norway". Geological Magazine 151, n. 5 (29 ottobre 2013): 816–29. http://dx.doi.org/10.1017/s0016756813000885.

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AbstractU–Pb and Lu–Hf isotope analyses of detrital zircon from the latest Ordovician (Hirnantian) Langøyene Formation, the Late Silurian Ringerike Group and the Late Carboniferous Asker Group in the Oslo Rift were obtained by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Overall the U–Pb dating yielded ages within the range 2861–313 Ma. The U–Pb age and Lu–Hf isotopic signatures correspond to virtually all known events of crustal evolution in Fennoscandia, as well as synorogenic intrusions from the Norwegian Caledonides. Such temporally and geographically diverse source areas likely reflect multiple episodes of sediment recycling in Fennoscandia, and highlights the intrinsic problem of using zircon as a tracer-mineral in ‘source to sink’ sedimentary provenance studies. In addition to its mostly Fennoscandia-derived detritus, the Asker Group also have zircon grains of Late Devonian – Late Carboniferous age. Since no rocks of these ages are known in Fennoscandia, these zircons are inferred to be derived from the Variscan Orogen of central Europe.

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Ershova, Victoria, Andrei Prokopiev e Daniel Stockli. "Provenance of Detrital Rutiles from the Triassic–Jurassic Sandstones in Franz Josef Land (Barents Sea Region, Russian High Arctic): U-Pb Ages and Trace Element Geochemistry". Geosciences 14, n. 2 (3 febbraio 2024): 41. http://dx.doi.org/10.3390/geosciences14020041.

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Provenance study plays an important role in paleogeographic and tectonic reconstructions. Detrital zircons are commonly used to identify sediment provenance; however, a wide range of detrital zircon ages in clastic rock often represent a fingerprint of reworked older terrigenous successions rather than ages of magmatism and metamorphism in the provenance area. This study focuses on the provenance of detrital rutile grains in the Triassic–Jurassic sandstones from Franz Josef Land and shows the importance of multiproxy approaches for provenance studies. Trace element data demonstrate that most rutile grains were sourced from metapelitic rocks, with a subordinate population having a metamafic origin. The Zr-in-rutile thermometer and U-Pb geochronology suggest that detrital rutile grains were predominantly derived from rocks that underwent amphibolite facies metamorphism during the Paleozoic era, with a predominance of the Carboniferous–Permian ages. Therefore, we suggest that the provenance area for the studied sandstones on Franz Josef Land has a similar geological history to the Taimyr region and Severnaya Zemlya archipelago. We propose that this crustal domain extends across the Kara Sea and forms the basement to the north and east of FJL, representing a proximal provenance for the studied Mesozoic terrigenous rocks. This domain experienced both Middle–Late Ordovician and Carboniferous–Permian metamorphism. The comparison of U-Pb dating and the geochemistry of rutile, U-Th/He, and U-Pb dating of zircons showed that detrital rutiles are the powerful toll in provenance restoration and can give additional constrains when a provenance area locates within collisional-convergent settings.

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Corfu, F., e J. Wood. "U–Pb zircon ages in supracrustal and plutonic rocks; North Spirit Lake area, Northwestern Ontario". Canadian Journal of Earth Sciences 23, n. 7 (1 luglio 1986): 967–77. http://dx.doi.org/10.1139/e86-098.

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The North Spirit Lake greenstone belt in the Sachigo Subprovince of the Superior Province comprises parts of three sequences of volcanic and sedimentary rocks; the main (youngest) is separated from the older sequences by an unconformity to disconformity. The belt is bounded by large granitoid batholiths and was metamorphosed under greenschist to, locally, hornblende–cordierite facies. U–Pb zircon dating was performed on volcanic, sedimentary, and plutonic rocks in order to establish an absolute chronology for the evolution of the area.A tuff breccia in the lowermost supracrustal sequence is dated at 3023 ± 2 Ma. Zircons from a tuff in the middle sequence show complex U–Pb relationships; although they do not allow a precise age determination, the data suggest that the tuff formed sometime between 2950 and 2800 Ma ago. Zircons from a quartz arenite, also in the middle sequence, yield a simple data pattern and define an age of [Formula: see text], suggesting derivation of the sediment from a uniform source of this age. A zircon analysis from a tonalitic clast in a conglomerate at the base of the upper sequence yields a minimum age of 2975 Ma. The clast may have had the same origin as the zircons in the quartz arenite. Another tonalitic clast from the same conglomerate yields a slightly older age of 3001 ± 3 Ma. No remnant of these tonalites can be recognized in the field, suggesting that they have been largely removed during subsequent erosional processes.Two subvolcanic intrusions from the upper sequence yield zircon ages of 2743 ± 2 and 2731 ± 2 Ma, respectively. A crystal tuff, also in the upper sequence, contains two generations of zircons: newly formed magmatic zircons, which date the extrusion of the tuff at 2735 ± 10 Ma, and older grains with a minimum age of 2862 Ma, which represent inherited zircons. This tuff was thus generated at least in part by anatectic melting of >2862 Ma crust.A quartz diorite from MacDowell Lake in the adjacent Berens River Subprovince yields an age of 2744 ± 2 Ma. A mafic inclusion in the quartz diorite contains amoeboidal, strongly fractured zircons, which point to an intercept age of about 2727 Ma. This age could either reflect a metamorphic event or represent a geologically meaningless mixed age.

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Chang, Zhaoshan, J. D. Vervoort, W. C. McClelland e C. Knaack. "LA-ICP-MS U-Pb dating of zircons: Error assessment". Geochimica et Cosmochimica Acta 70, n. 18 (agosto 2006): A96. http://dx.doi.org/10.1016/j.gca.2006.06.105.

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Krautz, Jana, Mandy Hofmann, Andreas Gärtner, Ulf Linnemann e Arno Kleber. "Capability of U–Pb dating of zircons from Quaternary tephra: Jemez Mountains, NM, and La Sal Mountains, UT, USA". E&G Quaternary Science Journal 67, n. 1 (31 gennaio 2018): 7–16. http://dx.doi.org/10.5194/egqsj-67-7-2018.

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Abstract. Two Quaternary tephras derived from the Jemez Mountains, New Mexico – the Guaje and Tsankawi tephras – are difficult to distinguish due to their similar glass-shard chemical composition. Differences in bulk chemical composition are small as well. Here we examine the feasibility to assign an age to a distal tephra layer in the La Sal Mountains, Utah, by U–Pb dating of zircons and to correlate it with one of the two Jemez eruptions. We also dated original Jemez tephras for comparison. Even though the tephras are very young, we obtained reasonable age determinations using the youngest cluster of zircon grains overlapping in age at 2σ. Thereafter, the Guaje tephra is 1.513 ± 0.021 Myr old. The La Sal Mountains tephra is correlated with the Tsankawi tephra. Three samples yielded a common age range of 1.31–1.40 Myr. All ages are in slight disagreement with published age determinations obtained by 40Ar ∕ 39Ar dating. These findings indicate that distal Jemez tephras can be distinguished by U–Pb dating. Furthermore, we encourage giving this method a try for age assignments even of Quaternary volcanic material.

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KOLODNER, K., D. AVIGAD, M. McWILLIAMS, J. L. WOODEN, T. WEISSBROD e S. FEINSTEIN. "Provenance of north Gondwana Cambrian–Ordovician sandstone: U–Pb SHRIMP dating of detrital zircons from Israel and Jordan". Geological Magazine 143, n. 3 (31 marzo 2006): 367–91. http://dx.doi.org/10.1017/s0016756805001640.

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A vast sequence of quartz-rich sandstone was deposited over North Africa and Arabia during Early Palaeozoic times, in the aftermath of Neoproterozoic Pan-African orogeny and the amalgamation of Gondwana. This rock sequence forms a relatively thin sheet (1–3 km thick) that was transported over a very gentle slope and deposited over a huge area. The sense of transport indicates unroofing of Gondwana terranes but the exact provenance of the siliciclastic deposit remains unclear. Detrital zircons from Cambrian arkoses that immediately overlie the Neoproterozoic Arabian–Nubian Shield in Israel and Jordan yielded Neoproterozoic U–Pb ages (900–530 Ma), suggesting derivation from a proximal source such as the Arabian–Nubian Shield. A minor fraction of earliest Neoproterozoic and older age zircons was also detected. Upward in the section, the proportion of old zircons increases and reaches a maximum (40%) in the Ordovician strata of Jordan. The major earliest Neoproterozoic and older age groups detected are 0.95–1.1, 1.8–1.9 and 2.65–2.7 Ga, among which the 0.95–1.1 Ga group is ubiquitous and makes up as much as 27% in the Ordovician of Jordan, indicating it is a prominent component of the detrital zircon age spectra of northeast Gondwana. The pattern of zircon ages obtained in the present work reflects progressive blanketing of the northern Arabian–Nubian Shield by Cambrian–Ordovician sediments and an increasing contribution from a more distal source, possibly south of the Arabian–Nubian Shield. The significant changes in the zircon age signal reflect many hundreds of kilometres of southward migration of the provenance.

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Pelech, Ondrej, Anna Vozárová, Pavel Uher, Igor Petrík, Dušan Plašienka, Katarína Šarinová e Nikolay Rodionov. "Late Permian volcanic dykes in the crystalline basement of the Považský Inovec Mts. (Western Carpathians): U–Th–Pb zircon SHRIMP and monazite chemical dating". Geologica Carpathica 68, n. 6 (1 agosto 2017): 530–42. http://dx.doi.org/10.1515/geoca-2017-0035.

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AbstractThis paper presents geochronological data for the volcanic dykes located in the northern Považský Inovec Mts. The dykes are up to 5 m thick and tens to hundreds of metres long. They comprise variously inclined and oriented lenses, composed of strongly altered grey-green alkali basalts. Their age was variously interpreted and discussed in the past. Dykes were emplaced into the Tatricum metamorphic rocks, mostly consisting of mica schists and gneisses of the Variscan (early Carboniferous) age. Two different methods, zircon SHRIMP and monazite chemical dating, were applied to determine the age of these dykes. U-Pb SHRIMP dating of magmatic zircons yielded the concordia age of 260.2 ± 1.4 Ma. The Th-U-Pb monazite dating of the same dyke gave the CHIME age of 259 ± 3Ma. Both ages confirm the magmatic crystallization at the boundary of the latest Middle Permian to the Late Permian. Dyke emplacement was coeval with development of the Late Paleozoic sedimentary basin known in the northern Považský Inovec Mts. and could be correlated with other pre-Mesozoic Tethyan regions especially in the Southern Alps.

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Sun, Xilin, Klaudia F. Kuiper, Yuntao Tian, Chang’an Li, Zengjie Zhang e Jan R. Wijbrans. "Comparison of Detrital Zircon U-Pb and Muscovite 40Ar/39Ar Ages in the Yangtze Sediment: Implications for Provenance Studies". Minerals 10, n. 7 (20 luglio 2020): 643. http://dx.doi.org/10.3390/min10070643.

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Detrital zircon U-Pb and muscovite 40Ar/39Ar dating are useful tools for investigating sediment provenance and regional tectonic histories. However, the two types of data from same sample do not necessarily give consistent results. Here, we compare published detrital muscovite 40Ar/39Ar and zircon U-Pb ages of modern sands from the Yangtze River to reveal potential factors controlling differences in their provenance age signals. Detrital muscovite 40Ar/39Ar ages of the major tributaries and main trunk suggest that the Dadu River is a dominant sediment contributor to the lower Yangtze. However, detrital zircon data suggest that the Yalong, Dadu, and Min rivers are the most important sediment suppliers. This difference could be caused by combined effects of lower reaches dilution, laser spot location on zircons and difference in closure temperature and durability between muscovite and zircon. The bias caused by sediment laser spot targeting a core or rim of zircon and zircon reworking should be considered in provenance studies.

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Peucat, J. J., D. Tisserant, R. Caby e N. Clauer. "Resistance of zircons to U–Pb resetting in a prograde metamorphic sequence of Caledonian age in East Greenland". Canadian Journal of Earth Sciences 22, n. 3 (1 marzo 1985): 330–38. http://dx.doi.org/10.1139/e85-033.

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In the Alpefjord area, Caledonian metamorphism from the chlorite zone to the sillimanite zone is seen to cut across the sedimentary pile of the lower Eleonore Bay Group. Zircons have been collected from quartzite layers enriched in heavy minerals.U–Pb zircon dating in the chlorite and the sillimanite zones does not reveal the Caledonian event but, instead, previous episodes at 1100 and 2500 Ma ago. The Caledonian event can be recognized in anatectic gneisses where detrital zircons are surrounded by overgrowths, K–Ar and Rb–Sr methods yield 1030–410 Ma ages on micas, with a positive correlation between the degree of apparent reselling of mica ages and the grade of the Caledonian metamorphism.The following geological interpretation of the age data is proposed. (1) A major metamorphic event occurred around 1100 Ma ago in the source area for the lower Eleonore Bay Group sediments. During this Grenvillian event, Archaean detrital zircons were affected by an episodic lead loss and a muscovite phase recorded the cooling and uplift of a basement source area. (2) Erosion of this source area occurred after 1100 Ma, followed by sedimentation of the lower Eleonore Bay Group [Formula: see text]. The 2500–1100 Ma U–Pb system remained nearly a closed system during Caledonian metamorphism up to and including sillimanite-zone conditions.This example shows the great resistance or inherited zircons to an important secondary Pb loss during Caledonian metamorphism and consequently shows that the lower-intercept ages of zircons from metasedimentary rocks do not always record the last metamorphic event observed in situ, but retain memories of previous geological events in the sedimentary source areas. By contrast, zircons separated from quartzitic xenoliths in migmatitic gneisses have recorded a disturbance in their U–Pb systems that corresponds to Caledonian partial melting.

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Ivanov, A. V., E. F. Letnikova, S. I. Shkolnik, A. V. Maslov e N. I. Vetrova. "EARLY CAMBRIAN DEPOSITS OF THE CONTINENTAL MARGIN (SOUTH OF TUVA, TEREGTIG FORMATION): RESULTS OF U–Pb DATING OF DETRITAL ZIRCONS AND Sr-CHEMOSTRATIGRAPHY". Доклады Российской академии наук. Науки о Земле 512, n. 2 (1 ottobre 2023): 165–73. http://dx.doi.org/10.31857/s2686739722602034.

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The sedimentation interval (530–520 Ma) of the Teregtig Formation deposits in southern Tuva is estimated based on U–Pb dating of detrital zircons from terrigenous deposits and Sr-chemostratigraphy of carbonate rocks. The main source area for clastic material, containing a large amount of detrital zircon grains, were rocks with an age of 580 Ma. The presence of a wide diversity of Precambrian detrital zircons indicates that sedimentation of the Teregtig Formation took place within a block of continental crust with a long evolutionary history. The presence of numerous chromites in their matrix indicates that the rocks of the Agardag ophiolite complex were also part of the eroded land during the accumulation of conglomerates of the Teregtig Formation.

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Götze, J., U. Kempe, D. Habermann, L. Nasdala, R. D. Neuser e D. K. Richter. "High-resolution cathodoluminescence combined with SHRIMP ion probe measurements of detrital zircons". Mineralogical Magazine 63, n. 2 (aprile 1999): 179–87. http://dx.doi.org/10.1180/002646199548411.

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AbstractCathodoluminescence (CL) microscopy and spectroscopy combined with SHRIMP ion probe measurements were carried out on detrital zircons from the Cretaceous Weferlingen quartz sand (Germany) to distinguish and characterize different zircon populations.Investigations by CL microscopy, SEM-CL and BSE imaging show that there are three main types of zircons (general grain sizes of 100–200 µm): (1) apparently weakly zoned, rounded grains with relict cores, (2) well rounded fragments of optically more or less homogeneous zircon grains showing CL zoning predominantly parallel to the z-axis, and (3) idiomorphic to slightly rounded zircon grains typically showing oscillatory euhedral CL zoning. A fourth type of low abundance is characterized by well-rounded grain fragments with an irregular internal structure showing bright yellow CL.High-resolution CL spectroscopic analyses reveal that blue CL is mainly caused by an intrinsic emission band centered near 430 nm. Dy3+ is the dominant activator element in all zircons, whereas Sm3+, Tb3+, Nd3+ have minor importance. Yellow CL (emission band between 500 and 700 nm) is probably caused by electron defects localized on the [SiO4] groups (e.g. related to oxygen vacancies) or activation by Yb2+ generated by radiation. Variations of the integral SEM-CL intensity are mainly controlled by the intensity of the broad bands and the Dy3+ peaks.SHRIMP analysis provides in situ high-resolution U-Pb dating of single zircon grains and confirms different ages for the evaluated different zircon types. The measurements show that the U-Pb ages of the zircons from Weferlingen scatter over a wide range (340 to 1750 Ma), backing up earlier conclusions that the quartz sand from Weferlingen is quite heterogeneous in terms of provenance.

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Sheikh, Lawangin, Wasiq Lutfi, Zhidan Zhao e Muhammad Awais. "Geochronology, trace elements and Hf isotopic geochemistry of zircons from Swat orthogneisses, Northern Pakistan". Open Geosciences 12, n. 1 (25 giugno 2020): 148–62. http://dx.doi.org/10.1515/geo-2020-0109.

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AbstractIn this study, zircon grains are applied for U–Pb dating, Hf isotopes and trace elements to reveal the origin of magmatism and tectonic evolution of Late Paleozoic rocks of the Indian plate, Northern Pakistan. Most of the zircons are characterized by oscillatory zoning, depletion of light rare earth elements (LREE) and enrichment of heavy rare earth elements (HREE) with Ce and Eu anomalies. The yielded ages for these rocks are 256 ± 1.9 Ma and are plotted in the zones defined for the continental setting with few deviated toward the mid-oceanic ridge and the oceanic arc setting. Deviated zircons are recognized as inherited zircons by displaying a high concentration of normalized primitive La and Pr values, while others are plotted in the continental zones. Rare earth elements (REE) and trace elements including Th, Hf, U, Nb, Sc and Ti discriminate Swat orthogneisses into the within plate setting and the inherited zircons are plotted in the orogenic or the arc-related setting. The LREE discriminated these zircons into a magmatic zone with inherited zircons deviated toward the hydrothermal zone. The temperature calculated for these rocks based on the Ti content in zircon ranges from 679 to 942°C. The εHf(t) ranging from −11.1 to +1.4 reveals that the origin is the continental crust with the minute input of the juvenile mantle.

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Krasnobaev, A. A., P. M. Valizer e N. N. Farrakhova. "Zircons of fenites of Ilmeno-Vishnevogorsky Complex (Southern Urals)". LITHOSPHERE (Russia) 21, n. 3 (8 luglio 2021): 306–22. http://dx.doi.org/10.24930/1681-9004-2021-21-3-306-322.

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Research subject. U-Pb zircon dating, as well as a petrological and geochemical study of pyroxene-amphibole-, pyroxeneamphibole- biotite- and biotite-bearing fenites from the Central Alkaline Band Ilmeno-Vishnevogorsky Complex.Methods. The age of zircons was determined by an ion mass spectrometer (SHRIMP II, Centre of Isotopic Research VSEGEI). The content of REE and trace elements was estimated by secondary ion mass spectrometer methods (CAMECA IMS-4F, Valiev Institute of Physics and Technology RAS).Results. The mineralogical and geochemical (U, Th, REE) features of zircons, as well as fenites, reflect their polygenic-polychronous nature. Most zircon crystals have a metastable matrix and are characterized by averaged REE contents between igneous and hydrothermal types. These crystals are distinguished from magmatic zircons by high LREE contents and low values of Ce anomalies, and from hydrothermal zircons – by differentiated REE distribution spectra. Three ages of zircon were established: 2066–1686 (PR1), 425–404 (S2) and 284–266 (P1) Ma. PR1 zircons reflect the primary features and the degree of changes in the fenite substrate. S2 zircons, limited only to the biotite- bearing fenite, correspond to the age of the miaskite formation process. The P1 zircons clearly reflect the metasomatic process of fenitization initiated by late shear deformations. The temperature of the phenitization processes (based on the Ti content in zircons) was estimated at 630–670°C for S2 and ≤ 600°C for P1 fenites, respectively.Conclusions. Central Alkaline Band fenites were formed by the metasomatic process of PR1 substrate fenitization in the late stage (P1) of shear strains, which are widely expressed in the Ilmeno-Vishnevogorsky Complex.

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Akinin, V. V., A. V. Alshevsky, G. O. Polzunenkov, S. A. Sergeev e V. A. Sidorov. "AGE OF NATALKA OROGENIC GOLD DEPOSIT (U-PB, 40AR/39AR, RE-OS CONSTRAIN)". Tikhookeanskaya Geologiya 42, n. 6 (2023): 62–79. http://dx.doi.org/10.30911/0207-4028-2023-42-6-62-79.

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Geological observations and U-Pb dating of zircons from intrusions of the Yana-Kolyma gold province constrain the age of orogenic gold deposits to the time interval between 150 ± 3 Ma and 108 ± 1 Ma. The age of mineralization at Natalka, the largest deposit of key importance in the gold province, is Valanzhinian (136 ± 1 to 132 ± 2 Ma) as we determined by muscovite 40Ar/39Ar dating and Re-Os dating of arsenopyrite and native gold. Since magmatic events of such ages are unknown in the province we conclude that the formation of gold-quartz mineralization is very likely related to metamorphism and metasomatism triggered by regional-scale shear deformation.

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Zhang, Xiaoran, Chia-Yu Tien, Sun-Lin Chung, Adi Maulana, Musri Mawaleda, Mei-Fei Chu e Hao-Yang Lee. "A Late Miocene magmatic flare-up in West Sulawesi triggered by Banda slab rollback". GSA Bulletin 132, n. 11-12 (8 aprile 2020): 2517–28. http://dx.doi.org/10.1130/b35534.1.

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Abstract Cenozoic magmatism occurs throughout West Sulawesi, Indonesia, yet its detailed evolution remains enigmatic due mainly to the scarcity of precise dating. Here, we report new whole-rock geochemical and zircon U-Pb-Hf isotopic data of plutonic/volcanic rocks and river sediments from West Sulawesi to constrain the petrogenesis and magmatic tempo. The magmatic rocks are intermediate to felsic (SiO2 = 58.1–68.0 wt%), high-K calc-alkaline to shoshonitic (K2O = 2.2–6.0 wt%), metaluminous to weakly peraluminous, and I-type in composition. Trace element concentrations and ratios (e.g., Nb/U = 1.7–4.3 and Ti/Zr < 28), along with negative zircon εHf(t) values (–17.0 to –0.4) and old crustal model ages (TDMC = 2.1–1.1 Ga), indicate a dominant magma source region from the underlying continental crystalline basement. U-Pb dating on zircons from ten magmatic rocks yielded weighted mean 206Pb/238U ages of 7.2–6.1 Ma, best representing the crystallization ages of host magmas, further consistent with the prominent age peaks (7.3–6.3 Ma) defined by detrital zircons from four sedimentary samples. Our new data, combined with available results, allow the identification of a noticeable climax of magmatism (flare-up) at ca. 7–6 Ma, forming a continuous magmatic belt throughout West Sulawesi. Given the absence of contemporaneous subduction and the coincidence of incipient opening of the South Banda Basin during ca. 7.15–6.5 Ma, the Late Miocene magmatic flare-up in West Sulawesi and coeval regional extension in eastern Indonesia are attributed to a resumed episode of Banda slab rollback.

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Creaser, Robert A., Larry M. Heaman e Philippe Erdmer. "Timing of high-pressure metamorphism in the Yukon – Tanana terrane, Canadian Cordillera: constraints from U – Pb zircon dating of eclogite from the Teslin tectonic zone". Canadian Journal of Earth Sciences 34, n. 5 (1 maggio 1997): 709–15. http://dx.doi.org/10.1139/e17-057.

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Zircon from eclogite near Last Peak in the Teslin tectonic zone yielded a U–Pb isotopic age of 269 + 2 Ma (2σ), the first precise age for such a rock in the Yukon –Tanana terrane of the Canadian Cordillera. Both the morphology and geochemistry of the eclogitic zircons indicate a metamorphic origin, and the U – Pb age therefore constrains the timing of peak high-pressure metamorphism in this rock. The U – Pb age demonstrates for the first time that an Early Permian high-pressure metamorphic event occurred in rocks now making up the Teslin tectonic zone, and possibly elsewhere in the Yukon – Tanana terrane. This U – Pb age provides a new geochronologic "pin" in the evolution of the Yukon – Tanana terrane prior to its Mesozoic accretion to the North American continental margin and, combined with recent 40Ar/39Ar muscovite data, indicates that high-pressure metamorphism at this time was a relatively short-lived event.

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