Journal articles: 'Zircon trace element geochemistry'

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Bolhar, R., A. Hofmann, C. M. Allen, and R. Maas. "A LA-ICPMS zircon record of magmatic crystallization and compositional alteration in meta-igneous rocks of the eastern Kaapvaal Craton." South African Journal of Geology 124, no. 3 (September 1, 2021): 761–82. http://dx.doi.org/10.25131/sajg.124.0042.

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Abstract Archaean zircons from the Kaapvaal Craton, South Africa, were analyzed by Laser Ablation (LA)-ICP-MS to obtain a coupled record of U-Th-Pb isotope ratios and selected trace elements with the aim to develop insights into physico-chemical conditions during igneous zircon crystallization and subsequent compositional alteration. Four rock samples previously dated by SIMS U-Pb using zircon were selected: 3.56 Ga Ngwane Gneiss, 3.55 Ga Theespruit felsic metavolcanic, 3.50 Ga Steynsdorp Gneiss and 2.98 Ga Nhlangano Gneiss. LA-ICP-MS U-Pb zircon ages agree with published SIMS U-Pb ages within analytical uncertainty. Assessment of the magmatic crystallization histories was based on near-concordant grains, and discordant grains were used to examine post-igneous element mobilization and alteration. Time-resolved laser drilling experiments allowed distinction of concordant and discordant zircon domains, but also revealed systematic changes in REE + Ti geochemistry, U + Th content, discordance and metamictization. Th/U and Zr/Hf, coupled with REE patterns, effectively distinguish compositional zircon types that reflect variable degrees of igneous differentiation and melt compositions. Eu/Eu* values indicate significant feldspar fractionation in some magmas. Averaged crystallization temperatures of magmatic zircons, as derived from the Ti-in-zircon thermometer, define a narrow range of 650 to 750°C for (near-)concordant grains, consistent with general constraints on temperatures at zircon saturation for felsic magmas, and testifying to a closed-system behavior of Ti (and other trace elements). Systematic deviations from primary igneous trace element signatures are strongly correlated with radiation damage. Specifically, Th/U and, to some extent, Zr/Hf decrease, and Ti increases with increasing U (+Th) content and isotopic disturbance (discordance).

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Verdel, Charles, Matthew J. Campbell, and Charlotte M. Allen. "Detrital zircon petrochronology of central Australia, and implications for the secular record of zircon trace element composition." Geosphere 17, no. 2 (February 5, 2021): 538–60. http://dx.doi.org/10.1130/ges02300.1.

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Abstract Hafnium (Hf) isotope composition of zircon has been integrated with U-Pb age to form a long-term (>4 b.y.) record of the evolution of the crust. In contrast, trace element compositions of zircon are most commonly utilized in local- or regional-scale petrological studies, and the most noteworthy applications of trace element studies of detrital zircon have been in “fingerprinting” potential source lithologies. The extent to which zircon trace element compositions varied globally over geological time scales (as, for example, zircon U-Pb age abundance, O isotope composition, and Hf isotope composition seem to have varied) has been little explored, and it is a topic that is well suited to the large data sets produced by detrital zircon studies. In this study we present new detrital zircon U-Pb ages and trace element compositions from a continent-scale basin system in Australia (the Centralian Superbasin) that bear directly on the Proterozoic history of Australia and which may be applicable to broader interpretations of plate-tectonic processes in other regions. U-Pb ages of detrital zircon in the Centralian Superbasin are dominated by populations of ca. 1800, 1600, 1200, and 600 Ma, and secular variations of zircon Hf isotope ratios are correlated with some trace element parameters between these major age populations. In particular, elevated εHf(i) (i.e., radiogenic “juvenile” Hf isotope composition) of detrital zircon in the Centralian Superbasin tends to correspond with relatively high values of Yb/U, Ce anomaly, and Lu/Nd (i.e., depletion of light rare earth elements). These correlations seem to be fundamentally governed by three related factors: elemental compatibility in the continental crust versus mantle, the thickness of continental crust, and the contributions of sediment to magmas. Similar trace element versus εHf(i) patterns among a global zircon data set suggest broad applicability. One particularly intriguing aspect of the global zircon data set is a late Neoproterozoic to Cambrian period during which both zircon εHf(i) and Yb/U reached minima, marking an era of anomalous zircon geochemistry that was related to significant contributions from old continental crust.

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Zhong, Shihua, Chengyou Feng, Reimar Seltmann, Daxin Li, and Hongying Qu. "Can magmatic zircon be distinguished from hydrothermal zircon by trace element composition? The effect of mineral inclusions on zircon trace element composition." Lithos 314-315 (August 2018): 646–57. http://dx.doi.org/10.1016/j.lithos.2018.06.029.

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Lee, Robert G., Alain Plouffe, Travis Ferbey, Craig J. R. Hart, Pete Hollings, and Sarah A. Gleeson. "RECOGNIZING PORPHYRY COPPER POTENTIAL FROM TILL ZIRCON COMPOSITION: A CASE STUDY FROM THE HIGHLAND VALLEY PORPHYRY DISTRICT, SOUTH-CENTRAL BRITISH COLUMBIA." Economic Geology 116, no. 4 (June 1, 2021): 1035–45. http://dx.doi.org/10.5382/econgeo.4808.

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Abstract The detrital zircons in tills overlying the Guichon Creek batholith, British Columbia, Canada, have trace element concentrations and ages similar to those of zircons from the bedrock samples from which they are interpreted to have been sourced. Rocks from the core of the batholith that host porphyry copper mineralization have distinct zircon compositions relative to the distal, barren margin. We analyzed 296 zircons separated from 12 subglacial till samples to obtain U-Pb ages and trace element compositions. Laser ablation U-Pb ages of the detrital zircons overlap within error with chemical abrasion-thermal ionization mass spectrometry U-Pb ages of the Late Triassic Guichon Creek batholith and confirm that the detrital zircons are likely derived from the batholith. The youngest intrusions of the batholith produced the Highland Valley Copper porphyry deposits and contain distinctive zircons with elevated Eu/EuN* >0.4 attributed to high magmatic water contents and oxidation states, indicating higher porphyry copper potential. Zircon from till samples adjacent to and 9 km down-ice from the mineralized centers have mean Eu/EuN* >0.4, which are indicative of potential porphyry copper mineralization. Detrital zircon grains from more distal up- and down-ice locations (10–15 km) have zircon Eu/EuN* mean values of 0.26 to 0.37, reflecting background values. We conclude that detrital zircon compositions in glacial sediments transported several kilometers can be used to establish the regional potential for porphyry copper mineralization.

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DeGraaff Surpless, Kathleen, Diane Clemens-Knott, Andrew P. Barth, and Michelle Gevedon. "A survey of Sierra Nevada magmatism using Great Valley detrital zircon trace-element geochemistry: View from the forearc." Lithosphere 11, no. 5 (June 27, 2019): 603–19. http://dx.doi.org/10.1130/l1059.1.

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AbstractThe well-characterized Sierra Nevada magmatic arc offers an unparalleled opportunity to improve our understanding of continental arc magmatism, but present bedrock exposure provides an incomplete record that is dominated by Cretaceous plutons, making it challenging to decipher details of older magmatism and the dynamic interplay between plutonism and volcanism. Moreover, the forearc detrital record includes abundant zircon formed during apparent magmatic lulls, suggesting that understanding the long-term history of arc magmatism requires integrating plutonic, volcanic, and detrital records. We present trace-element geochemistry of detrital zircon grains from the Great Valley forearc basin to survey Sierra Nevadan arc magmatism through Mesozoic time. We analyzed 257 previously dated detrital zircon grains from seven sandstone samples of volcanogenic, arkosic, and mixed compositions deposited ca. 145–80 Ma along the length of the forearc basin. Detrital zircon trace-element geochemistry is largely consistent with continental arc derivation and shows similar geochemical ranges between samples, regardless of location along strike of the forearc basin, depositional age, or sandstone composition. Comparison of zircon trace-element data from the forearc, arc, and retroarc regions revealed geochemical asymmetry across the arc that was persistent through time and demonstrated that forearc and retroarc basins sampled different parts of the arc and therefore recorded different magmatic histories. In addition, we identified a minor group of Jurassic detrital zircon grains with oceanic geochemical signatures that may have provenance in the Coast Range ophiolite. Taken together, these results suggest that the forearc detrital zircon data set reveals information different from that gleaned from the arc itself and that zircon compositions can help to identify and differentiate geochemically distinct parts of continental arc systems. Our results highlight the importance of integrating multiple proxies to fully document arc magmatism, demonstrating that detrital zircon geochemical data can enhance understanding of a well-characterized arc, and these data may prove an effective means by which to survey an arc that is inaccessible and therefore poorly characterized.

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Filina, Maria I., Elena S. Sorokina, Roman Botcharnikov, Stefanos Karampelas, Mikhail A. Rassomakhin, Natalia N. Kononkova, Anatoly G. Nikolaev, Jasper Berndt, and Wolfgang Hofmeister. "Corundum Anorthosites-Kyshtymites from the South Urals, Russia: A Combined Mineralogical, Geochemical, and U-Pb Zircon Geochronological Study." Minerals 9, no. 4 (April 16, 2019): 234. http://dx.doi.org/10.3390/min9040234.

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Kyshtymites are the unique corundum-blue sapphire-bearing variety of anorthosites of debatable geological origin found in the Ilmenogorsky-Vishnevogorsky complex (IVC) in the South Urals, Russia. Their mineral association includes corundum-sapphire, plagioclase (An61–93), muscovite, clinochlore, and clinozoisite. Zircon, churchite-(Y), monazite-(Ce), and apatite group minerals are found as accessory phases. Besides, churchite-(Y) and zircon are also identified as syngenetic solid inclusions within the sapphires. In situ Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) U-Pb zircon geochronology showed the ages at about 290–330 Ma linked to the Hercynian orogeny in IVC. These ages are close to those of the syenitic and carbonatitic magmas of the IVC, pointing to their syngenetic origin, which is in agreement with the trace element geochemistry of the zircons demonstrating clear magmatic signature. However, the trace element composition of sapphires shows mostly metamorphic signature with metasomatic overprints in contrast to the geochemistry of zircons. The reason for this discrepancy can be the fact that the discrimination diagrams for sapphires are not as universal as assumed. Hence, they cannot provide an unambiguous determination of sapphire origin. If it is true and zircons can be used as traces of anorthosite genesis, then it can be suggested that kyshtymites are formed in a magmatic process at 440–420 Ma ago, most probably as plagioclase cumulates in a magma chamber. This cumulate rock was affected by a second magmatic event at 290–330 Ma as recorded in zircon and sapphire zoning. On the other hand, Ti-in-zircon thermometer indicates that processes operated at relatively lower temperature (<900 °C), which is not enough to re-melt the anorthosites. Hence, zircons in kyshtymites can be magmatic but inherited from another rock, which was re-worked during metamorphism. The most probable candidate for the anorthosite protolith is carbonatites assuming that metamorphic fluids could likely leave Al- and Si-rich residue, but removed Ca and CO2. Further, Si is consumed by the silicification of ultramafic host rocks. However, kyshtymites do not show clear evidence of pronounced metasomatic zonation and evidence for large volume changes due to metamorphic alteration of carbonatites. Thus, the obtained data still do not allow for univocal reconstruction of the kyshtymite origin and further investigations are required.

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Sepahi, Ali A., Hamed Vahidpour, David R. Lentz, Chris RM McFarlane, Mohammad Maanijou, Sedigheh Salami, Mirmohammad Miri, Mehrak Mansouri, and Razieh Mohammadi. "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 (February 24, 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 > 2) exists. This silica-undersaturated pegmatite and its sapphire crystals have a primary igneous origin. U–Pb zircon geochronology of three separate samples from this pegmatite indicates the following ages: 168 ± 1 Ma, 166 ± 1 Ma and 164 ± 1 Ma. The zircon grains have notable amounts of Hf (up to 17 200 ppm), U (up to 13 580 ppm), Th (up to 5148 ppm), Y (up to 4764 ppm) and ∑REE (up to 2534 ppm). There is a positive correlation between Hf and Th, Nb and Ta, U and Th, and Y and HREE and a negative correlation between Hf and Y values in the zircons. These zircons exhibit pronounced positive Ce anomalies (Ce/Ce* = 1.15–68.06) and negative Eu anomalies (Eu/Eu* = 0.001–0.56), indicative of the relatively oxidized conditions of the parent magma. Ti-in-zircon thermometry reveals temperatures from as low as ~683 °C up to ~828 °C (average = 755° ± 73 °C). Zircon and monazite saturation equilibria are also consistent with these temperatures. Zircon grains are magmatic (average La < 1.5, (Sm/La)N > 100 and Th/U > 0.7), with chemical characteristics similar to zircons from continental crust.

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Sheikh, Lawangin, Wasiq Lutfi, Zhidan Zhao, and Muhammad Awais. "Geochronology, trace elements and Hf isotopic geochemistry of zircons from Swat orthogneisses, Northern Pakistan." Open Geosciences 12, no. 1 (June 25, 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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Clayton, T., J. E. Francis, S. J. Hillier, F. Hodson, R. A. Saunders, and J. Stone. "The implications of reworking on the mineralogy and chemistry of Lower Carboniferous K-bentonites." Clay Minerals 31, no. 3 (September 1996): 377–90. http://dx.doi.org/10.1180/claymin.1996.031.3.08.

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AbstractPotassium-bentonites have been found in the Courceyan Lower Limestone Shales near Burrington Combe and Oakhill, Somerset, consisting of thin, greenish yellow, plastic clays interbedded within a mudrock and limestone sequence. Mineralogically, the clay fraction is composed of virtually monomineralic interstratified illite-smectite containing 7–10% smectite layers. The clay fraction of the surrounding mudrocks, however, consists of an illite-chlorite dominated assemblage. Their mineral composition, trace element content, and the relative abundance of zircon crystals suggest an origin from burial of montmorillonite originally formed from volcanic ash. The presence of anomalously high trace element contents with both euhedral and rounded zircon grains in the Oakhill K-bentonites suggests a secondary or reworked origin for these samples. In contrast, the presence of a non-anomalous trace element content and large (>100 μm) euhedral zircon grains suggests that the Burrington K-bentonite is primary in origin. Modelling of whole-rock rare-earth element (REE) patterns shows that the Oakhill REE pattern can be derived from the Burrington pattern by the addition of small contributions from zircon and monazite, two major heavy minerals present. These K-bentonites probably represent the oldest Carboniferous K-bentonites so far recorded in the British Isles.

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Wang, X., W. L. Griffin, S. Y. O’Reilly, X. M. Zhou, X. S. Xu, S. E. Jackson, and N. J. Pearson. "Morphology and geochemistry of zircons from late Mesozoic igneous complexes in coastal SE China: implications for petrogenesis." Mineralogical Magazine 66, no. 2 (April 2002): 235–51. http://dx.doi.org/10.1180/0026461026620025.

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AbstractThe Pingtan and Tonglu igneous complexes in SE China are typical of the calc-alkaline series developed at active continental margins. These two complexes are dominated by felsic rocks, temporally and spatially associated with minor mafic rocks. Morphological and trace-element studies of zircon populations in rocks from each of these complexes show that the zircon populations may be divided into 3–4 distinct growth stages, characterized by different distributions of morphological indices (Ipr, Ipy and Iel), and different contents of the substituting elements (Hf, U, Th, Y and P). The four growth stages recognized in the zircons are believed to have formed successively in the magma chamber, during the emplacement, and in the early and later stages of magma consolidation, respectively. All four stages are recognized in the plutonic Pingtan complex, whereas the stages 3 and 4 are less developed in the volcanic/subvolcanic Tonglu complex. Based on the chemistry and morphology of the different zircon populations of the Pingtan and Tonglu complexes, it is suggested that basaltic magmas underplating at the boundary between crust and mantle caused partial melting of the mid–lower crust and produced granitoid magmas. Subsequently, mixing between magmas was important.

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Schärer, Urs, Jasper Berndt, and Alex Deutsch. "The genesis of deep-mantle xenocrystic zircon and baddeleyite megacrysts (Mbuji-Mayi kimberlite): trace-element patterns." European Journal of Mineralogy 23, no. 2 (May 3, 2011): 241–55. http://dx.doi.org/10.1127/0935-1221/2011/0023-2088.

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Drabon, Nadja, Benjamin L. Byerly, Gary R. Byerly, Joseph L. Wooden, C. Brenhin Keller, and Donald R. Lowe. "Heterogeneous Hadean crust with ambient mantle affinity recorded in detrital zircons of the Green Sandstone Bed, South Africa." Proceedings of the National Academy of Sciences 118, no. 8 (February 18, 2021): e2004370118. http://dx.doi.org/10.1073/pnas.2004370118.

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The nature of Earth’s earliest crust and the processes by which it formed remain major issues in Precambrian geology. Due to the absence of a rock record older than ∼4.02 Ga, the only direct record of the Hadean is from rare detrital zircon and that largely from a single area: the Jack Hills and Mount Narryer region of Western Australia. Here, we report on the geochemistry of Hadean detrital zircons as old as 4.15 Ga from the newly discovered Green Sandstone Bed in the Barberton greenstone belt, South Africa. We demonstrate that the U-Nb-Sc-Yb systematics of the majority of these Hadean zircons show a mantle affinity as seen in zircon from modern plume-type mantle environments and do not resemble zircon from modern continental or oceanic arcs. The zircon trace element compositions furthermore suggest magma compositions ranging from higher temperature, primitive to lower temperature, and more evolved tonalite-trondhjemite-granodiorite (TTG)-like magmas that experienced some reworking of hydrated crust. We propose that the Hadean parental magmas of the Green Sandstone Bed zircons formed from remelting of mafic, mantle-derived crust that experienced some hydrous input during melting but not from the processes seen in modern arc magmatism.

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XinYu, ZOU, JIANG JiLian, QIN KeZhang, ZHANG YiGang, YANG Wei, and Li XianHua. "Progress in the principle and application of zircon trace element." Acta Petrologica Sinica 37, no. 4 (2021): 985–99. http://dx.doi.org/10.18654/1000-0569/2021.04.03.

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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 (February 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 the cores. The 207Pb/206Pb rim ages can be temporally correlated with regional magmatism and with a later, potentially Au-bearing, hydrothermal event synchronous with greenschist-facies metamorphism and regional deformation. Notably, the zircons do not record evidence of local ca. 2741–2715 Ma magmatism manifested by the emplacement of a quartz–feldspar porphyry dike swarm. Laser ablation – inductively coupled plasma – mass spectrometry (LA–ICP–MS) REE depth profile analyses on the same unpolished zircon show that the rims are commonly characterized by low Th/U ratios, elevated Hf, and variable REE concentrations in comparison with the interior of the grains. The variations in rim and core chemistry suggest that these elements, along with common Pb, were mobilized by fluids and interacted with zircon in the metasediments, resulting in the production of the metasomatic rims. In summary, this paper shows that depth profiling techniques applied to unpolished zircon can be useful to elucidate the tectonic, and potentially metallogenic, history of a complex Archean terrane.

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Chen, Shao-Rong, Qing Wang, Di-Cheng Zhu, Roberto F. Weinberg, Liang-Liang Zhang, and Zhi-Dan Zhao. "Reheating and Magma Mixing Recorded by Zircon and Quartz from High-Silica Rhyolite in the Coqen Region, Southern Tibet." American Mineralogist 106, no. 1 (January 1, 2021): 112–22. http://dx.doi.org/10.2138/am-2020-7426.

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Abstract Understanding the formation of high-silica rhyolites (HSRs, SiO2 = 75 wt%) is critical to revealing the evolution of felsic magma systems and magma chamber processes. This paper addresses HSR petrogenesis by investigating an integrated data set of whole-rock geochemistry, geochronology, and mineral composition of the ~74 Ma Nuocang HSR (SiO2 = 74.5–79.3 wt%) from the Coqen region in southern Tibet. Cathodoluminescence (CL) images show that zircons from the Nuocang HSRs can be divided into two textural types: (1) those with dark-CL cores displaying resorption features and overgrown by light-CL rims, and (2) those comprising a single light-CL zone, without dark-CL cores. In situ single-spot data and scanning images demonstrate that these two types of zircon have similar U-Pb ages (~74 Ma) and Hf isotopic compositions [εHf(t) = –9.09 to –5.39], indicating they were generated by the same magmatic system. However, they have different abundances of trace elements and trace element ratios. The dark-CL cores are likely crystallized from a highly evolved magma as indicated by their higher U, Th, Hf, Y, and heavy rare earth elements concentrations, lower Sm/Yb ratio, and more negative Eu anomalies. In contrast, the uniformly light-CL zircons and the light-CL rims are likely crystallized from less evolved and hotter magma, as indicated by their lower U-Th-REE abundances and higher Ti-in-zircon temperatures. This is consistent with the Ti-in-quartz geothermometer in quartz phenocrysts that reveals that the light-CL zones are hotter than dark-CL cores. We propose that the composition and temperature differences between cores and rims of zircons and quartz record a recharge and reheating event during the formation of the Nuocang HSRs. This implies that HSR is a result of mixing between a hotter, less evolved silicic magma and a cooler, highly evolved, and crystal-rich mush. This study shows that zircon and quartz with distinct internal textures can be combined to disentangle the multi-stage evolution of magma reservoirs, providing critical insights into the origin of HSRs.

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Piilonen, P. C., A. M. McDonald, G. Poirier, R. Rowe, and A. O. Larsen. "The mineralogy and crystal chemistry of alkaline pegmatites in the Larvik Plutonic Complex, Oslo rift valley, Norway. Part 1. Magmatic and secondary zircon: implications for petrogenesis from trace-element geochemistry." Mineralogical Magazine 76, no. 3 (June 2012): 649–72. http://dx.doi.org/10.1180/minmag.2012.076.3.15.

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AbstractA detailed electron microprobe (EMP) and laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) study of zircon from six types of miaskitic and agpaitic alkaline pegmatite from the Larvik Plutonic Complex, Oslo rift valley, Norway, was undertaken to shed light on the pegmatite petrogenesis. Detailed rare earth element (REE) analyses indicate important differences between the zircon from each type of pegmatite. Primary zircon from miaskitic Stavern-, Tvedalen- and Stålaker-type pegmatites has a mean ΣREE = 704 ppm, is depleted in LREE and has a significant positive Ce anomaly (Ce/Ce* = 44–67) and negative Eu anomaly (Eu/Eu* = 0.15–0.18). Secondary Tvedalen-type zircon is REE-enriched (ΣREE = 5035 ppm), with a flatter REE pattern, Ce/Ce* = 0.97 and a Eu anomaly similar to primary Tvedalen-type zircon (Eu/Eu* = 0.21). Secondary zircon from agpaitic Langesundsfjord-type pegmatites display a distinctive flat REE pattern characterized by overall REE enrichment (ΣREE = 967), Ce/Ce* = 1.92, and a minor negative Eu anomaly (Eu/Eu* = 0.37). Zircon from agpaitic Bratthagen-type pegmatites occurs as both altered primary and secondary phases and is strongly enriched in REE relative to other zircon (ΣREE = 4178 and 8388, respectively). Primary Bratthagen-type zircon has a similar REE pattern to miaskitic zircon, with a steeper HREE profile and smaller Ce and Eu anomalies (Eu/Eu* = 0.73; Ce/Ce* = 6.22). Secondary Bratthagen-type zircon is strongly enriched in LREE compared to primary zircon, does not display a positive Ce anomaly and has Eu/Eu* = 0.56. The altered primary and secondary Bratthagen-type zircons have elevated Th/UN ratios, suggesting a different melt source for Bratthagen-type agpaitic pegmatites. Zircon from external pegmatites has trace-element signatures similar to Stavern-, Tvedalen- and Staålaker-type primary zircon with Ce/Ce* = 214 and Nb/Ta and Th/U ratios that are similar to those of secondary Langesundsfjord- and Bratthagen-type zircon. It is suggested that the parental melt of the external pegmatites is the same as the miaskitic pegmatites, but that it has undergone alteration by hydrothermal fluids derived from the host basalt, or by post-magmatic F-rich fluids which mobilize Nb and Th. On the basis of texture, morphology and geochemistry, two populations of zircon can be recognized: (1) primary zircon from miaskitic pegmatites; and (2) secondary zircon from post-magmatic, hydrothermal assemblages. The U–Th–Pb isotope analyses indicate that the secondary and altered zircon are depleted in 238U, and enriched in LREE. Interaction of a post-magmatic hydrothermal fluid with an externally derived meteoric fluid is suggested to have influenced the REE signatures, and in particular the Eu and Ce anomalies of the late-stage zircons.

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Zhang, Xin, Feng-Jun Nie, Fei Xia, Cheng-Yong Zhang, Zhi-Bing Feng, Rahman Ullah, and Peng-Fei Zhang. "Provenance constraints on the Xishanyao Formation, southern Yili Basin, northwest China: evidence from petrology, geochemistry, and detrital zircon U–Pb geochronology." Canadian Journal of Earth Sciences 55, no. 9 (September 2018): 1020–35. http://dx.doi.org/10.1139/cjes-2017-0258.

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We conducted petrographic, geochemical, and new U–Pb laser ablation inductively coupled mass spectrometry analyses of detrital zircons in the sandstone samples from the important Mengqiguer sandstone-type uranium deposit located in the Yili basin of the Xishanyao Formation. This formation (Shuixigou Group) is a major uranium-bearing target stratum in the basin. The main purpose of our investigations was to determine the provenance of the host sand units that has remained unclear to date. Our petrographic results suggested that the host sandstone is texturally and chemically immature, indicating superior physicochemical conditions for later uranium mineralisation. The major and trace element data of the detrital sandstone samples point towards the upper continental crust, and the chondrite-normalised rare earth element (REE) plots show enriched light REE and relatively flat heavy-REE distribution, with a negative Eu anomaly. The characteristics of the REEs and the trace elements point to felsic rocks as the provenance of the target strata with a continental arc tectonic setting. The detrital zircons indicate an age span of ∼235–∼2327 Ma, with major age populations of ∼300–∼500 Ma. The increasing amount of zircon grains from the Late Devonian to the Early Carboniferous coinciding with the age of volcanic magmatic activities of the Wusun and Nalati mountains indicates that the rocks formed under the Tianshan collisional orogeny and the subsequent extensional environment.

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Sutherland, F. L., R. R. Coenraads, A. Abduriyim, S. Meffre, P. W. O. Hoskin, G. Giuliani, R. Beattie, R. Wuhrer, and G. B. Sutherland. "Corundum (sapphire) and zircon relationships, Lava Plains gem fields, NE Australia: Integrated mineralogy, geochemistry, age determination, genesis and geographical typing." Mineralogical Magazine 79, no. 3 (June 2015): 545–81. http://dx.doi.org/10.1180/minmag.2015.079.3.04.

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AbstractGem minerals at Lava Plains, northeast Queensland, offer further insights into mantle-crustal gemformation under young basalt fields. Combined mineralogy, U-Pb age determination, oxygen isotope and petrological data on megacrysts and meta-aluminosilicate xenoliths establish a geochemical evolution in sapphire, zircon formation between 5 to 2 Ma. Sapphire megacrysts with magmatic signatures (Fe/Mg ∼100–1000, Ga/Mg 3–18) grew with ∼3 Ma micro-zircons of both mantle (δ18O 4.5–5.6%) and crustal (δ18O 9.5–10.1‰) affinities. Zircon megacrysts (3±1 Ma) show mantle and crustal characteristics, but most grew at crustal temperatures (600–800°C). Xenolith studies suggest hydrous silicate melts and fluids initiated from amphibolized mantle infiltrated into kyanite+sapphire granulitic crust (800°C, 0.7 GPa). This metasomatized the sapphire (Fe/Mg ∼50–120, Ga/Mg ∼3–11), left relict metastable sillimanite-corundum-quartz and produced minerals enriched in high field strength, large ion lithophile and rare earth elements. The gem suite suggests a syenitic parentage before its basaltic transport. Geographical trace-element typing of the sapphire megacrysts against other eastern Australian sapphires suggests a phonolitic involvement.

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Xia, Qiong-Xia, Peng Gao, Guang Yang, Yong-Fei Zheng, Zi-Fu Zhao, Wan-Cai Li, and Xu Luo. "The Origin of Garnets in Anatectic Rocks from the Eastern Himalayan Syntaxis, Southeastern Tibet: Constraints from Major and Trace Element Zoning and Phase Equilibrium Relationships." Journal of Petrology 60, no. 11 (November 1, 2019): 2241–80. http://dx.doi.org/10.1093/petrology/egaa009.

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Abstract Amphibolite- and granulite-facies metamorphic rocks are common in the eastern Himalayan syntaxis of southeastern Tibet. These rocks are composed mainly of gneiss, amphibolite and schist that underwent various degrees of migmatization to produce leucogranites, pegmatites and felsic veins. Zircon U–Pb dating of biotite gneiss, leucocratic vein and vein granite from the syntaxis yields consistent ages of ∼49 Ma, indicating crustal anatexis during continental collision between India and Asia. Garnets in these rocks are categorized into peritecitc and anatectic varieties based on their mode of occurrence, mineral inclusions and major- and trace-element zoning. The peritectic garnets mainly occur in the biotite gneiss (mesosome layer) and leucocratic veins. They are anhedral and contain abundant mineral inclusions such as high-Ti biotites and quartz, and show almost homogeneous major-element compositions (except Ca) and decreasing HREE contents from core to rim, indicating growth during the P- and T-increasing anatexis. Peak anatectic conditions at 760–800°C and 9–10·5 kbar are well constrained by phase equilibrium calculations, mineral assemblages, and garnet isopleths. In contrast, anatectic garnets only occur in the vein granite. They are round or subhedral, contain quartz inclusions, and exhibit increasing spessartine and trace-element contents from core to rim. The garnet–biotite geothermometry and the garnet–biotite–plagioclase–quartz geobarometry suggest that the anatectic garnets crystallized at ∼620–650°C and 4–5 kbar. Some garnet grains show two-stage zoning in major and trace elements, with the core similar to the peritectic garnet but the rim similar to the anatectic garnet. Mineralogy, whole-rock major- and trace-element compositions and zircon O isotopes indicate that the two types of leucosomes were produced by hydration (water-present) melting and dehydration (water-absent) melting, respectively. The leucocratic veins contain peritectic garnet but no K-feldspar, have lower whole-rock K2O contents and Rb/Sr ratios, higher whole-rock CaO contents and Sr/Ba ratios, and show homogeneous δ18O values that are lower than those of relict zircons, indicating that such veins were produced by the hydration melting. In contrast, the vein granite contains peritectic garnet and K-feldspar, has higher whole-rock K2O contents and Rb/Sr ratios, lower whole-rock CaO contents and Sr/Ba ratios, and shows comparable δ18O values with those of relict zircons, suggesting that this granite were generated by the dehydration melting. Accordingly, both hydration and dehydration melting mechanisms have occurred in the eastern Himalayan syntaxis.

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Mordberg, L. E., C. J. Stanley, and K. Germann. "Mineralogy and geochemistry of trace elements in bauxites: the Devonian Schugorsk deposit, Russia." Mineralogical Magazine 65, no. 1 (February 2001): 81–101. http://dx.doi.org/10.1180/002646101550145.

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AbstractProcesses of mineral alteration involving the mobilization and deposition of more than 30 chemical elements during bauxite formation and epigenesis have been studied on specimens from the Devonian Schugorsk bauxite deposit, Timan, Russia. Chemical analyses of the minerals were obtained by electron microprobe and element distribution in the minerals was studied by element mapping. Interpretation of these data also utilized high-resolution BSE and SE images.The main rock-forming minerals of the Vendian parent rock are calcite, dolomite, feldspar, aegirine, riebeckite, mica, chlorite and quartz; accessory minerals are pyrite, galena, apatite, ilmenite, monazite, xenotime, zircon, columbite, pyrochlore, chromite, bastnaesite and some others. Typically, the grainsize of the accessory minerals in both parent rock and bauxite is from 1 to 40 µm. However, even within these rather small grains, the processes of crystal growth and alteration during weathering can be determined from the zonal distribution of the elements. The most widespread processes observed are: (1) Decomposition of Ti-bearing minerals such as ilmenite, aegirine and riebeckite with the formation of ‘leucoxene’, which is the main concentrator of Nb, Cr, V and W. Crystal growth can be traced from the zonal distribution of Nb (up to 16 wt.%). Vein-like ‘leucoxene’ is also observed in association with organics. (2) Weathering of columbite and pyrochlore: the source of Nb in ‘leucoxene’ is now strongly weathered columbite, while the alteration of pyrochlore is expressed in the growth of plumbopyrochlore rims around Ca-rich cores. (3) Dissolution of sulphide minerals and apatite and the formation of crandallite group minerals: ‘crandallite’ crystals of up to 40 µm size show a very clear zonation. From the core to the rim of a crystal, the following sequence of elements is observed: Ca → Ba → Ce → Pb → Sr → Nd. Sulphur also shows a zoned but more complicated distribution, while the distribution of Fe is rather variable. A possible source of REE is bastnaesite from the parent rock. More than twelve crandallite type cells can be identified in a single ‘crandallite’ grain. (4) Alteration of stoichiometric zircon and xenotime with the formation of metamict solid solution of zircon and xenotime: altered zircon rims also bear large amounts of Sc (up to 3.5 wt.%), Fe, Ca and Al in the form of as yet unidentified inclusions of 1–2 µm. Monazite seems to be the least altered mineral of the profile.In the parent rock, an unknown mineral of the composition (wt.%): ThO2 – 54.8; FeO – 14.6; Y2O5 – 2.3; CaO – 2.0; REE – 1.8; SiO2 12.2; P2O5 – 2.8; total – 94.2 (average from ten analyses) was determined. In bauxite, another mineral was found, which has the composition (wt.%): ThO2 – 24.9; FeO – 20.5; Y2O5 – 6.7; CaO 2.0; – ZrO – 17.6; SiO2 – 8.8; P2O5 – 5.4; total – 89.3 (F was not analysed; average from nine analyses). Presumably, the second mineral is the result of weathering of the first one. Although the Th content is very high, the mineral is almost free of Pb. However, intergrowths of galena and pyrite are observed around the partially decomposed crystals of the mineral. Another generation of galena is enriched in chalcophile elements such as Cu, Cd, Bi etc., and is related to epigenetic alteration of the profile, as are secondary apatite and muscovite.

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Crow, Carolyn A., Kevin D. McKeegan, and Desmond E. Moser. "Coordinated U–Pb geochronology, trace element, Ti-in-zircon thermometry and microstructural analysis of Apollo zircons." Geochimica et Cosmochimica Acta 202 (April 2017): 264–84. http://dx.doi.org/10.1016/j.gca.2016.12.019.

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No, Sang-Gun, and Maeng-Eon Park. "The Geochronology and Geochemistry of Zircon as Evidence for the Reconcentration of REE in the Triassic Period in the Chungju Area, South Korea." Minerals 10, no. 1 (January 5, 2020): 49. http://dx.doi.org/10.3390/min10010049.

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The Chungju rare-earth element (REE) deposit is located in the central part of the Okcheon Metamorphic Belt (OMB) in the Southern Korean Peninsula and research on REE mineralization in the Gyemyeongsan Formation has been continuous since the first report in 1989. The genesis of the REE mineralization that occurred in the Gyemyeongsan Formation has been reported by previous researchers; theories include the fractional crystallization of alkali magma, magmatic hydrothermal alteration, and recurrent mineralization during metamorphism. In the Gyemyeongsan Formation, we discovered an allanite-rich vein that displays the paragenetic relationship of quartz, allanite, and zircon, and we investigated the chemistry and chronology of zircon obtained from this vein. We analyzed the zircon’s chemistry with an electron probe X-ray micro analyzer (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The grain size of the zircon is as large as 50 µm and has an inherited core (up to 15 µm) and micrometer-sized sector zoning (up to several micrometers in size). In a previous study, the zircon ages were not obtained because the grain size was too small to analyze. In this study, we analyzed the zircon with laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) for dating purposes. The REE patterns and occurrence of zircon in the quartz–allanite vein match well with previous reported recrystallized zircon, while the behavior of the trace elements shows differences with magmatic and hydrothermal zircon. The 206Pb/238U ages obtained from the zircon in the quartz–allanite vein are from 240.1 ± 2.9 to 257.1 ± 3.5 Ma and this age is included in the tectonic evolution period of the study area. Therefore, we suggest that the quartz–allanite veins in the Gyemyeongsan Formation were formed during the late Permian to early Triassic metamorphic period and the zircon was recrystallized at that time. The Triassic age is the first reported age with zircon dating in the Gyemyeongsan Formation and will be an important data-point for the study of the tectonic evolution of the OMB.

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23

Mattinson, C. G., J. L. Wooden, J. X. Zhang, and D. K. Bird. "Paragneiss zircon geochronology and trace element geochemistry, North Qaidam HP/UHP terrane, western China." Journal of Asian Earth Sciences 35, no. 3-4 (July 2009): 298–309. http://dx.doi.org/10.1016/j.jseaes.2008.12.007.

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24

Breiter, Karel, Axel Müller, Robin Shail, and Beth Simons. "Composition of zircons from the Cornubian Batholith of SW England and comparison with zircons from other European Variscan rare-metal granites." Mineralogical Magazine 80, no. 7 (December 2016): 1273–89. http://dx.doi.org/10.1180/minmag.2016.080.071.

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AbstractZircon from 14 representative granite samples of the late-Variscan Cornubian Batholith in SW England was analysed for W, P, As, Nb, Ta, Si, Ti, Zr, Hf, Th, U, Y, La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb, Al, Sc, Bi, Mn, Fe, Ca, Pb, Cu, S and F using electron probe microanalyses. Zircons from the biotite and tourmaline granites are poor in minor and trace elements, usually containing 1.0–1.5 wt.% HfO2, <0.5 wt.% UO2 and P2O5, <0.25 wt.% Y2O3, <0.2 wt.% Sc2O3 and Bi2O3 and <0.1 wt.% ThO2. Zircon from topaz granites from the St. Austell Pluton, Meldon Aplite and Megiliggar Rocks are slightly enriched in Hf (up to 4 wt.% HfO2), U (1– 3.5 wt.% UO2) and Sc (0.5–1 wt.% Sc2O3). Scarce metamictized zircon grains are somewhat enriched in Al, Ca, Fe and Mn. The decrease of the zircon Zr/Hf ratio, a reliable magma fractionation index, from 110–60 in the biotite granites to 30–10 in the most evolved topaz granites (Meldon Aplite and Megiliggar Rocks), supports a comagmatic origin of the biotite and topaz granites via long-lasting fractionation of common peraluminous crustal magma. In comparison with other European rare-metal provinces, the overall contents of trace elements in Cornubian zircons are low and the Zr/Hf and U/Th ratios show lower degrees of fractionation of the parental melt.

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Paulsen, Timothy, Chad Deering, Jakub Sliwinski, Olivier Bachmann, and Marcel Guillong. "New detrital zircon age and trace element evidence for 1450 Ma igneous zircon sources in East Antarctica." Precambrian Research 300 (October 2017): 53–58. http://dx.doi.org/10.1016/j.precamres.2017.07.011.

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Yan, Li-Li, Zhen-Yu He, Reiner Klemd, Christoph Beier, and Xi-Sheng Xu. "Tracking crystal-melt segregation and magma recharge using zircon trace element data." Chemical Geology 542 (June 2020): 119596. http://dx.doi.org/10.1016/j.chemgeo.2020.119596.

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CAO, Ye, Shengrong LI, Huafeng ZHANG, Xiaobin LIU, Zhenzhen LI, Chong AO, and Meijuan YAO. "Significance of zircon trace element geochemistry, the Shihu gold deposit, western Hebei Province, North China." Journal of Rare Earths 29, no. 3 (March 2011): 277–86. http://dx.doi.org/10.1016/s1002-0721(10)60445-0.

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Tuisku, P., H. Huhma, and M. J. Whitehouse. "Geochronology and geochemistry of the enderbite series in the Lapland Granulite Belt: generation, tectonic setting, and correlation of the belt1NORDSIM Publication No. 322." Canadian Journal of Earth Sciences 49, no. 11 (November 2012): 1297–315. http://dx.doi.org/10.1139/e2012-065.

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The Lapland Granulite Belt of the northeastern Fennoscandian Shield is dominated by blastomylonitic migmatitic metagreywackes and a deformed, structurally conformable norite–enderbite series. The belt contains minor granodiorites and one major anorthosite massif and is crosscut by post-tectonic granite plutons and diabase dykes. The major and trace element composition of the enderbite series is similar to that of arc-related igneous rocks. Magmatically zoned zircon yield U–Pb secondary ion mass spectrometry ages of 1.91–1.92 Ga, while homogeneous metamorphic zircon domains are aged 1.88–1.90 Ga. Major enderbite bodies reveal only a few older inherited, xenocrystic zircon cores or grains, mainly Archaean in age, while a tonalite body and a narrow quartz norite vein have abundant inherited zircons comparable with the detrital zircon population in the metagreywackes. The intrusive series has slightly positive initial εNdvalues, while the tonalite body has a slightly negative initial εNd, consistent with the occurrences of inherited zircon grains. The major intrusive series, interpreted to have been emplaced in an arc environment, has juvenile character and assimilated only a minor amount of older crustal material during ascent, intrusion, and cooling. Narrow veins and more evolved bodies had more interaction with the metasediments and other crustal rocks. The enderbite series of the Lapland Granulite Belt may be correlated with arc-related plutonism in the Nagssugtoqidian and Torngat orogens, but metamorphic and structural evolution took place considerably later in Greenland and the northeastern Canadian Shield, with the exception of the Inglefield Belt of northwestern Greenland.

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Zhang, Xue-Bing, Feng-Mei Chai, Chuan Chen, Hong-Yan Quan, Ke-Yong Wang, Shun-Da Li, and Shi-Shan Wu. "Using Whole Rock and Zircon Geochemistry to Assess Porphyry Copper Potential of the Tonggou Copper Deposit, Eastern Tianshan." Minerals 10, no. 7 (June 28, 2020): 584. http://dx.doi.org/10.3390/min10070584.

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Eastern Tianshan hosts a number of porphyry Cu deposits. However, these mainly formed in the Jueluotage Belt, in the middle part of Eastern Tianshan. The Tonggou porphyry Cu mineralization is an exception to this, since it is located in the Bogda Orogenic Belt, north of Eastern Tianshan. We obtained new zircon U-Pb ages, whole-rock geochemical data, zircon Hf isotope data, and zircon trace element compositions. LA-ICP-MS zircon U-Pb dating indicates a crystallization age of 302.2–303.0 Ma for the Tonggou mineralized granodiorite (TMG), which suggests that the Tonggou porphyry Cu mineralization formed in the Late Carboniferous period. εHf (t) data (1.8–14.1) for TMG suggests it was sourced from juvenile crustal melts, mixed with some mantle materials. TMG displays low ΣREE, compatible elements (Ba, Sr, Zr, and Hf), Zr/Hf and Nb/Ta ratios, as well as clearly negative Eu anomalies in whole rocks analyses. In addition, TMG is enriched in P, Hf and Th/U ratios in zircon, and has lower crystallization temperatures (734 to 735 °C) than the Daheyan barren granodiorite (DBG) (753 to 802 °C). Whole rock and zircon geochemical analyses show that the TMG was formed by fractional crystallization to a greater extent than the DBG in the Bogda Orogenic Belt. Moreover, zircon grains of the TMG show high Ce4+/Ce3+ ratios (159–286), which are consistent with related values from large porphyry deposits of the Central Asian Orogenic Belt (CAOB). High Ce4+/Ce3+ ratios reflect oxidizing magmas as a result of fractional crystallization, which indicates that the Tonggou deposit has potential to host a large porphyry Cu deposit.

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Bourne, James. "The geochemistry of the La Galissonnière Pluton: a Middle Proterozoic late-orogenic intrusion from the eastern Grenville Province, Quebec." Canadian Journal of Earth Sciences 28, no. 1 (January 1, 1991): 37–43. http://dx.doi.org/10.1139/e91-004.

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The La Galissonnière Pluton is a late-orogenic pluton located in the eastern Grenville Province of Quebec. The pluton contains biotite > hornblende, zircon, titanite, allanite, and apatite, along with secondary sericite and epidote. The pluton features elevated values of Nb, Y, and F. The normalized rare-earth element patterns have light rare-earth element concentrations of 400–500× chondrite, moderate slopes (10–20), and noticeable Eu anomalies. Trace-element discriminant diagrams suggest that the pluton formed in a late-orogenic environment and indicate a possible period of late Precambrian crustal attenuation in the eastern Grenville Province.

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Hartmann, Léo A., Sérgio B. Baggio, Matheus P. Brückmann, Daniel B. Knijnik, Cristiano Lana, Hans-Joachim Massonne, Joachim Opitz, et al. "U-Pb geochronology of Paraná volcanics combined with trace element geochemistry of the zircon crystals and zircon Hf isotope data." Journal of South American Earth Sciences 89 (January 2019): 219–26. http://dx.doi.org/10.1016/j.jsames.2018.11.026.

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32

Ngoniri, Alexis Hamdja, Habib Dadjo Djomo, Timoleon Ngnotue, Patrick Ayonta Kenne, Ghislain Ngassam Mbianya, Sylvestre Ganno, and Jean Paul Nzenti. "Zircon Trace Element Geochemistry and Ti-in-Zircon Thermometry of the Ngazi-Tina Pan-African Post-Collisional Granitoids, Adamawa Cameroon." International Journal of Geosciences 12, no. 04 (2021): 307–28. http://dx.doi.org/10.4236/ijg.2021.124017.

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33

Coble, Matthew A., Jorge A. Vazquez, Andrew P. Barth, Joseph Wooden, Dale Burns, Andrew Kylander-Clark, Simon Jackson, and Cara E. Vennari. "Trace Element Characterisation of MAD-559 Zircon Reference Material for Ion Microprobe Analysis." Geostandards and Geoanalytical Research 42, no. 4 (September 19, 2018): 481–97. http://dx.doi.org/10.1111/ggr.12238.

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34

Bhandari, Saunak, Wenjiao Xiao, Songjian Ao, Brian F. Windley, Rixiang Zhu, Rui Li, Hao Y. C. Wang, and Rasoul Esmaeili. "Rifting of the northern margin of the Indian craton in the Early Cretaceous: Insight from the Aulis Trachyte of the Lesser Himalaya (Nepal)." Lithosphere 11, no. 5 (July 12, 2019): 643–51. http://dx.doi.org/10.1130/l1058.1.

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Abstract To reconstruct the early tectonic history of the Himalayan orogen before final India-Asia collision, we carried out geochemical and geochronological studies on the Early Cretaceous Aulis Trachyte of the Lesser Himalaya. The trace-element geochemistry of the trachytic lava flows suggests formation in a rift setting, and zircon U-Pb ages indicate that volcanism occurred in Early Cretaceous time. The felsic volcanics show enrichment of more incompatible elements and rare earth elements, a pattern that is identical to the trachyte from the East African Rift (Kenya rift), with conspicuous negative anomalies of Nb, P, and Ti. Although much of the zircon age data are discordant, they strongly suggest an Early Cretaceous eruption age, which is in agreement with the fossil age of intravolcanic siltstones. The Aulis Trachyte provides the first corroboration of Cretaceous rifting in the Lesser Himalaya as suggested by paleomagnetic data associated with the concept that the northern margin of India separated as a microcontinent and drifted north in the Neo-Tethys before terminal collision of India with Asia.

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Feely, M., and J. S. Madden. "Trace element variation in the leucogranites within the main Galway Granite, Connemara, Ireland." Mineralogical Magazine 52, no. 365 (April 1988): 139–46. http://dx.doi.org/10.1180/minmag.1988.052.365.01.

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AbstractSix hundred and forty four gamma-ray spectrometer assays of U and Th obtained within the late Caledonian Galway Granite western Ireland are presented. The data cover the range of granodiorites, adamellites and leucogranites (Murvey Granite) present in the batholith. There is an overall increase in U and Th abundances with petrological evolution. The broad scatter of values that characterizes the Murvey Granite reflects the geographically separate occurrences of this leucogranite. Rubidium and strontium data imply varying degrees of fractionation among these separate Murvey Granite occurrences. Y and HREE are notably enriched in the Murvey granite at Costelloe which also contains the highest Th levels amongst the leucogranites. Thorite, uraninite, monazite and Y-zircon are present in this leucogranite and are responsible for the observed enrichments in U, Th, Y and HREE.

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Rubatto, Daniela. "Zircon trace element geochemistry: partitioning with garnet and the link between U–Pb ages and metamorphism." Chemical Geology 184, no. 1-2 (March 2002): 123–38. http://dx.doi.org/10.1016/s0009-2541(01)00355-2.

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Grimes, Craig B., Barbara E. John, Michael J. Cheadle, Frank K. Mazdab, Joseph L. Wooden, Susan Swapp, and Joshua J. Schwartz. "On the occurrence, trace element geochemistry, and crystallization history of zircon from in situ ocean lithosphere." Contributions to Mineralogy and Petrology 158, no. 6 (May 19, 2009): 757–83. http://dx.doi.org/10.1007/s00410-009-0409-2.

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38

Mc Clelland, William C., Jane A. Gilotti, Frank K. Mazdab, and Joseph L. Wooden. "Trace-element record in zircons during exhumation from UHP conditions, North-East Greenland Caledonides." European Journal of Mineralogy 21, no. 6 (January 28, 2010): 1135–48. http://dx.doi.org/10.1127/0935-1221/2009/0021-2000.

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Hofmann, Amy E., John W. Valley, E. Bruce Watson, Aaron J. Cavosie, and John M. Eiler. "Sub-micron scale distributions of trace elements in zircon." Contributions to Mineralogy and Petrology 158, no. 3 (February 15, 2009): 317–35. http://dx.doi.org/10.1007/s00410-009-0385-6.

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40

Zhu, Yudi, Yanpei Dai, Lili Wang, Di Xiu, and Chao Chen. "Geochemical and isotopic compositions of Late Permian metavolcano–sedimentary sequence in the southern Songpan–Ganzi Orogen, eastern Tibetan Plateau." Geological Magazine 157, no. 12 (April 21, 2020): 2004–20. http://dx.doi.org/10.1017/s0016756820000230.

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AbstractThe Permian metavolcano–sedimentary sequence of the Jianglang and Taka domes in the southern Songpan–Ganzi Orogen is composed of bedded marble and sandwiched metabasalt. This study presents geochemistry, C–O–Nd isotope systematics and zircon U–Pb geochronology data to explore the formation mechanism and tectonic setting of its protolith. The marble samples have high δ13CV-PDB (4.0 ‰ to −0.1 ‰) and δ18OV-SMOW (16.3 ‰ to 13.6 ‰) values, with similar εNd(t) values (−5.3 to −7.2) to Late Permian conodonts. They display seawater-like features, e.g. superchondritic Y/Ho ratios, negative Ce and positive La, Gd and Y anomalies, indicating a marine carbonate protolith in oxygen-rich palaeoseawater. Their pronounced positive Eu anomalies suggest a contribution (5 % to 1 %) of submarine high-T hydrothermal fluids. The metabasalt samples show low SiO2, high Fe2O3T and MgO contents. They have low La/Sm, (Th/Ta)PM and (La/Nb)PM ratios, without correlations between MgO and other major/trace elements. These signatures could be attributed to insignificant fractional crystallization and crustal contamination. Their rare earth elements (REE) patterns, trace element profiles and trace element ratios are comparable to those of mid-ocean ridge basalt (MORB), suggesting a depleted MORB-type mantle reservoir. Melt modelling illustrates low degrees (<10 %) of partial melting in the spinel stability field at a depth of 30–60 km. Moreover, the metabasalt contains 2453.7–258.9 Ma detrital zircons significantly related to the Palaeoproterozoic crystalline basement, Rodinia supercontinent, Caledonian events and c. 260 Ma Emeishan large igneous province. Combined with previous studies, we advocate that the investigated metavolcano–sedimentary suquence was most likely formed during the Late Permian in a mature back-arc basin of the Palaeo-Tethys ocean.

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de Liz, J. D., L. V. S. Nardi, E. F. de Lima, and K. Jarvis. "THE TRACE-ELEMENT RECORD IN ZIRCON FROM THE LAVRAS DO SUL SHOSHONITIC ASSOCIATION, SOUTHERNMOST BRAZIL." Canadian Mineralogist 47, no. 4 (August 1, 2009): 833–46. http://dx.doi.org/10.3749/canmin.47.4.833.

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Schulz, Bernhard, Reiner Klemd, and Helene Brätz. "Host rock compositional controls on zircon trace element signatures in metabasites from the Austroalpine basement." Geochimica et Cosmochimica Acta 70, no. 3 (February 2006): 697–710. http://dx.doi.org/10.1016/j.gca.2005.10.001.

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ZENG, QING-DONG, JIN-HUI YANG, JIAN-MING LIU, SHAO-XIONG CHU, XIAO-XIA DUAN, ZUO-LUN ZHANG, WEI-QING ZHANG, and SONG ZHANG. "Genesis of the Chehugou Mo-bearing granitic complex on the northern margin of the North China Craton: geochemistry, zircon U–Pb age and Sr–Nd–Pb isotopes." Geological Magazine 149, no. 5 (November 24, 2011): 753–67. http://dx.doi.org/10.1017/s0016756811000987.

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AbstractThe Chehugou granite-hosted molybdenum deposit is typical of the Xilamulun metallogenic belt, which is an important Mo–Ag–Pb–Zn producer in China. A combination of major and trace element, Sr and Nd isotope, and zircon U–Pb isotopic data are reported for the Chehugou batholith to constrain its petrogenesis and Mo mineralization. The zircon SIMS U–Pb dating yields mean ages of 384.7 ± 4.0 Ma and 373.1 ± 5.9 Ma for monzogranite and syenogranite and 265.6 ± 3.5 Ma and 245.1 ± 4.4 Ma for syenogranite porphyry and granite porphyry, respectively. The Devonian granites are calc-alkaline with K2O/Na2O ratios of 0.44–0.52, the Permian granites are alkali-calcic with K2O/Na2O ratios of 1.13–1.25, and the Triassic granites are calc-alkaline and alkali-calcic rocks with K2O/Na2O ratios of 0.78–1.63. They are all enriched in large-ion lithophile elements (LILEs) and depleted in high-field-strength elements (HFSEs) with negative Nb and Ta anomalies in primitive mantle-normalized trace element diagrams. They have relatively high Sr (189–1256 ppm) and low Y (3.87–5.43 ppm) concentrations. The Devonian granites have relatively high initial Sr isotope ratios of 0.7100–0.7126, negative ɛNd(t) values of −12.3 to −12.4 and 206Pb/204Pb ratios of 16.46–17.50. In contrast, the Permian and Triassic granitoids have relatively low initial 87Sr/86Sr ratios (0.7048–0.7074), negative ɛNd(t) values of −10.1 to −13.1 and 206Pb/204Pb ratios of 17.23–17.51. These geochemical features suggest that the Devonian, Permian and Triassic Chehugou granitoids were derived from ancient, garnet-bearing crustal rocks related to subduction of the Palaeo-Asian Ocean and subsequent continent–continent collision between the North China and Siberian plates.

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Anfinson, Owen A., Daniel F. Stockli, Joseph C. Miller, Andreas Möller, and Fritz Schlunegger. "Tectonic exhumation of the Central Alps recorded by detrital zircon in the Molasse Basin, Switzerland." Solid Earth 11, no. 6 (November 23, 2020): 2197–220. http://dx.doi.org/10.5194/se-11-2197-2020.

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Abstract. Eocene to Miocene sedimentary strata of the Northern Alpine Molasse Basin in Switzerland are well studied, yet they lack robust geochronologic and geochemical analysis of detrital zircon for provenance tracing purposes. Here, we present detrital zircon U–Pb ages coupled with rare-earth and trace element geochemistry to provide insights into the sedimentary provenance and to elucidate the tectonic activity of the central Alpine Orogen from the late Eocene to mid Miocene. Between 35 and 22.5 ± 1 Ma, the detrital zircon U–Pb age signatures are dominated by age groups of 300–370, 380–490, and 500–710 Ma, with minor Proterozoic age contributions. In contrast, from 21 Ma to ∼ 13.5 Ma (youngest preserved sediments), the detrital zircon U–Pb age signatures were dominated by a 252–300 Ma age group, with a secondary abundance of the 380–490 Ma age group and only minor contributions of the 500–710 Ma age group. The Eo-Oligocene provenance signatures are consistent with interpretations that initial basin deposition primarily recorded unroofing of the Austroalpine orogenic lid and lesser contributions from underlying Penninic units (including the Lepontine dome), containing reworked detritus from Variscan, Caledonian–Sardic, Cadomian, and Pan-African orogenic cycles. In contrast, the dominant 252–300 Ma age group from early Miocene foreland deposits is indicative of the exhumation of Variscan-aged crystalline rocks from the Lepontine dome basement units. Noticeable is the lack of Alpine-aged detrital zircon in all samples with the exception of one late Eocene sample, which reflects Alpine volcanism linked to incipient continent–continent collision. In addition, detrital zircon rare-earth and trace element data, coupled with zircon morphology and U∕Th ratios, point to primarily igneous and rare metamorphic sources. The observed switch from Austroalpine to Penninic detrital provenance in the Molasse Basin at ∼ 21 Ma appears to mark the onset of synorogenic extension of the Central Alps. Synorogenic extension accommodated by the Simplon fault zone promoted updoming and exhumation the Penninic crystalline core of the Alpine Orogen. The lack of Alpine detrital zircon U–Pb ages in all Oligo-Miocene strata corroborate the interpretations that between ∼ 25 and 15 Ma, the exposed bedrock in the Lepontine dome comprised greenschist-facies rocks only, where temperatures were too low for allowing zircon rims to grow, and that the Molasse Basin drainage network did not access the prominent Alpine-age Periadriatic intrusions located in the area surrounding the Periadriatic Line.

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Song, Dongfang, Wenjiao Xiao, Brian F. Windley, and Chunming Han. "Carboniferous to Early Triassic magmatism and accretion in Alxa (NW China): implications for accretionary orogenesis of the southern Altaids." Journal of the Geological Society 177, no. 5 (May 6, 2020): 997–1012. http://dx.doi.org/10.1144/jgs2020-046.

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Alxa occupies a crucial position between the Tianshan–Beishan orogen to the west and the Solonker suture to the east and is important in our understanding of the accretionary orogenesis of the southern Altaids. To unravel the tectonic history of the Alxa region, we undertook an integrated study of the field geology, geochemistry and geochronology of magmatic rocks and an accretionary complex. Six granites and one rhyolite from the Zhusileng–Hangwula arc show a peraluminous, high-K calc-alkaline composition and one gabbro is tholeiitic. They show patterns rich in incompatible elements and negative Nb–Ta anomalies on primitive mantle-normalized trace element spider diagrams. Laser ablation inductively coupled plasma mass spectrometry zircon U–Pb dating reveals 348–329 and 267–250 Ma magmatic events. These data indicate that the Zhusileng–Hangwula arc was a Japan-type island arc from the late Paleozoic to Early Triassic. The Engger Us mélange comprises pillow basalts with a normal-type mid-ocean ridge basalt composition, tuffs, cherts, siliceous mudstones, limestones and turbidites, which are tectonically juxtaposed by a block-in-matrix structure. This mélange is interpreted as a Carboniferous–Permian accretionary complex. These new data, combined with previous studies, confirm that the Palaeo-Asian Ocean subducted bidirectionally in the Alxa region in the Carboniferous–Early Triassic. A consistent divergent subduction system existed from Alxa to Solonker before the terminal closure of the Palaeo-Asian Ocean in the Mid- to Late Triassic.Supplementary material: Major and trace element data and zircon U-Pb age results of all the samples are available at: https://doi.org/10.6084/m9.figshare.c.4962230

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BRÖCKER, MICHAEL, and MICHAEL ENDERS. "U–Pb zircon geochronology of unusual eclogite-facies rocks from Syros and Tinos (Cyclades, Greece)." Geological Magazine 136, no. 2 (March 1999): 111–18. http://dx.doi.org/10.1017/s0016756899002320.

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Low-temperature eclogite-facies rocks from Syros and Tinos (Cyclades, Greece) include meta-igneous blocks of unclear origin (meta-olistostrome or tectonic mélange) with very high trace element concentrations (e.g. Zr up to 4850 ppm; Y up to 475 ppm). The unusual geochemistry is considered to be the result of metasomatic alteration in a subduction-zone environment. Locally, metasomatic exchange with an ultramafic matrix further enhanced compositional anomalies. A concordant U–Pb zircon age of 78±1 Ma recorded for an omphacitite from Syros is interpreted as the time of pre-Eocene high-pressure metamorphism in the Cyclades. Zircon dates of 61 and 63 Ma for a jadeitite from Tinos possibly indicate an additional discrete event (deformation?). These results are a first geochronological indication that high-pressure metamorphism in the Cyclades commenced significantly earlier than indicated by previous white mica chronology which provided ages between c. 50 and 40 Ma.

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Wong, Jacqueline, Charles Verdel, and Charlotte M. Allen. "Trace-element compositions of sapphire and ruby from the eastern Australian gemstone belt." Mineralogical Magazine 81, no. 6 (December 2017): 1551–76. http://dx.doi.org/10.1180/minmag.2017.081.012.

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AbstractSignificant uncertainty surrounds the processes involved in the formation of basalt-hosted corundum, particularly the role that the mantle plays in corundum generation. Some previous studies have suggested that trace-element ratios (namely, Cr/Ga and Ga/Mg) are useful for distinguishing two types of corundum: ‘magmatic’ and ‘metamorphic’, designations that include mantle and crustal processes. However, recent studies, including this one, have discovered transitional groups between these end-members that are difficult to classify.We used laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) to measure trace-element concentrations in sapphire and ruby crystals from eight alluvial deposits that span a significant length of the eastern Australian gemstone belt. Additionally, we collected LA–ICP–MS U–Pb and traceelement data from zircon megacrysts atWeldborough, Tasmania, which is also within the gemstone belt. Our sapphire and ruby results reveal a continuum in trace-element compositions, an observation that raises questions regarding previous classifications that ascribe corundum from basalt-hosted gemfields to either ‘magmatic’ or ‘metamorphic’ sources. The spatial association of basalt-related gemfields in eastern Australia with a long-lived convergent margin suggests a link between corundum formation and Al-enrichment of the mantle wedge during periods of subduction.

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Piilonen, Paula, F. Sutherland, Martin Danišík, Glenn Poirier, John Valley, and Ralph Rowe. "Zircon Xenocrysts from Cenozoic Alkaline Basalts of the Ratanakiri Volcanic Province (Cambodia), Southeast Asia—Trace Element Geochemistry, O-Hf Isotopic Composition, U-Pb and (U-Th)/He Geochronology—Revelations into the Underlying Lithospheric Mantle." Minerals 8, no. 12 (November 30, 2018): 556. http://dx.doi.org/10.3390/min8120556.

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Zircon xenocrysts from alkali basalts in Ratanakiri Province, Cambodia represent a unique low-Hf zircon within a 12,000 km long Indo-Pacific megacryst zone. Colorless, yellow, brown, and red crystals ({100}, {101}, subordinate {211}, {1103}), with hopper growth and corrosion features range up to 20 cm in size. Zircon chemistry indicates juvenile, Zr-saturated, mantle-derived alkaline melt (Hf 0.6–0.7 wt %, Y <0.2 wt %, U + Th + REE (Rare-Earth Elements) < 600 ppm, Zr/Hf 66–92, Eu/Eu*N ~1, positive Ce/Ce*N, HREE (Heavy REE) enrichment). Incompatible element depletion with increasing Yb/SmN from core to rim at ~ constant Hf suggests single stage growth. Ti-in-zircon temperatures (~570–740 °C) are lower than predicted by crystal morphology (800–900 °C) and decrease from core to rim (ΔT = 10–50 °C). The δ18O values (4.88 to 5.01‰ VSMOW (Vienna Standard Mean Ocean Water)) are relatively low for xenocrysts from the zircon Indo-Pacific zone (ZIP). The 176Hf/177Hf values (+ εHf 4.5–10.2) give TDepleted Mantle model source ages of 260–462 Ma and TCrustal ages of 391–754 Ma. The source magmas reflect variably depleted lithospheric mantle with little supracrustal input. Zircon U-Pb (0.88–1.56 Ma) and (U-Th)/He (0.86–1.02 Ma) ages are older than host basalt ages (~0.7 Ma), which suggests limited residence before transport. Zircon genesis suggests Zr-saturated, Al-undersaturated, carbonatitic-influenced, low-degree partial melting (<1%) of peridotitic mantle at ~60 km beneath the Indochina terrane.

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HOU, Zhenhui. "Sm-Nd and zircon SHRIMP U-Pb dating of Huilanshan mafic granulite in the Dabie Mountains and its zircon trace element geochemistry." Science in China Series D 48, no. 12 (2005): 2081. http://dx.doi.org/10.1360/03yd0524.

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ZHU, Yongfeng. "The zircon SHRIMP chronology and trace element geochemistry of the Carboniferous volcanic rocks in western Tianshan Mountains." Chinese Science Bulletin 50, no. 19 (2005): 2201. http://dx.doi.org/10.1360/03wd0154.

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Journal articles on the topic 'Zircon trace element geochemistry'

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