Journal articles on the topic 'Nd isotopes'
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1
Wu, Li, Ling, Yang, Li, Li, Mao, Li, and Putlitz. "Further Characterization of the RW-1 Monazite: A New Working Reference Material for Oxygen and Neodymium Isotopic Microanalysis." Minerals 9, no. 10 (September 26, 2019): 583. http://dx.doi.org/10.3390/min9100583.
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The oxygen (O) and neodymium (Nd) isotopic composition of monazite provides an ideal tracer of metamorphism and hydrothermal activity. Calibration of the matrix effect and monitoring of the external precision of monazite O–Nd isotopes with microbeam techniques, such as secondary ion mass spectrometry (SIMS) and laser ablation-multicollector-inductively coupled plasma-mass spectrometry (LA-MC-ICPMS), require well-characterized natural monazite standards for precise microbeam measurements. However, the limited number of standards available is impeding the application of monazite O–Nd isotopes. Here, we report on the RW-1 monazite as a potential new working reference material for microbeam analysis of O–Nd isotopes. Microbeam measurements by electron probe microanalysis (EPMA), SIMS, and LA-MC-ICPMS at 10–24 µm scales have confirmed that it is homogeneous in both elemental and O–Nd isotopic compositions. SIMS measurements yield δ18O values consistent, within errors, with those obtained by laser fluorination techniques. Precise analyses of Nd isotope by thermal ionization mass spectrometry (TIMS) are consistent with mean results of LA-MC-ICPMS analyses. We recommend δ18O = 6.30‰ ± 0.16‰ (2SD) and 143Nd/144Nd = 0.512282 ± 0.000011 (2SD) as being the reference values for the RW-1 monazite.
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Vezinet, Adrien, Emilie Thomassot, Yan Luo, Chiranjeeb Sarkar, and D. Graham Pearson. "Diachronous Redistribution of Hf and Nd Isotopes at the Crystal Scale—Consequences for the Isotopic Evolution of a Poly-Metamorphic Crustal Terrane." Geosciences 12, no. 1 (January 12, 2022): 36. http://dx.doi.org/10.3390/geosciences12010036.
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In metamorphic rocks, mineral species react over a range of pressure–temperature conditions that do not necessarily overlap. Mineral equilibration can occur at varied points along the metamorphic pressure–temperature (PT) path, and thus at different times. The sole or dominant use of zircon isotopic compositions to constrain the evolution of metamorphic rocks might then inadvertently skew geological interpretations towards one aspect or one moment of a rock’s history. Here, we present in-situ U–Pb/Sm–Nd isotope analyses of the apatite crystals extracted from two meta-igneous rocks exposed in the Saglek Block (North Atlantic craton, Canada), an Archean metamorphic terrane, with the aim of examining the various signatures and events that they record. The data are combined with published U–Pb/Hf/O isotope compositions of zircon extracted from the same hand-specimens. We found an offset of nearly ca. 1.5 Gyr between U-Pb ages derived from the oldest zircon cores and apatite U–Pb/Sm–Nd isotopic ages, and an offset of ca. 200 Ma between the youngest zircon metamorphic overgrowths and apatite. These differences in metamorphic ages recorded by zircon and apatite mean that the redistribution of Hf isotopes (largely hosted in zircon) and Nd isotopes (largely hosted in apatite within these rocks), were not synchronous at the hand-specimen scale (≤~0.001 m3). We propose that the diachronous redistribution of Hf and Nd isotopes and their parent isotopes was caused by the different PT conditions of growth equilibration between zircon and apatite during metamorphism. These findings document the latest metamorphic evolution of the Saglek Block, highlighting the role played by intra-crustal reworking during the late-Archean regional metamorphic event.
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van de Flierdt, Tina, Alexander M. Griffiths, Myriam Lambelet, Susan H. Little, Torben Stichel, and David J. Wilson. "Neodymium in the oceans: a global database, a regional comparison and implications for palaeoceanographic research." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, no. 2081 (November 28, 2016): 20150293. http://dx.doi.org/10.1098/rsta.2015.0293.
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The neodymium (Nd) isotopic composition of seawater has been used extensively to reconstruct ocean circulation on a variety of time scales. However, dissolved neodymium concentrations and isotopes do not always behave conservatively, and quantitative deconvolution of this non-conservative component can be used to detect trace metal inputs and isotopic exchange at ocean–sediment interfaces. In order to facilitate such comparisons for historical datasets, we here provide an extended global database for Nd isotopes and concentrations in the context of hydrography and nutrients. Since 2010, combined datasets for a large range of trace elements and isotopes are collected on international GEOTRACES section cruises, alongside classical nutrient and hydrography measurements. Here, we take a first step towards exploiting these datasets by comparing high-resolution Nd sections for the western and eastern North Atlantic in the context of hydrography, nutrients and aluminium (Al) concentrations. Evaluating those data in tracer–tracer space reveals that North Atlantic seawater Nd isotopes and concentrations generally follow the patterns of advection, as do Al concentrations. Deviations from water mass mixing are observed locally, associated with the addition or removal of trace metals in benthic nepheloid layers, exchange with ocean margins (i.e. boundary exchange) and/or exchange with particulate phases (i.e. reversible scavenging). We emphasize that the complexity of some of the new datasets cautions against a quantitative interpretation of individual palaeo Nd isotope records, and indicates the importance of spatial reconstructions for a more balanced approach to deciphering past ocean changes. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’.
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Jo, Hui Je, Hyo Min Lee, Go-Eun Kim, Won Myung Choi, and Taehoon Kim. "Determination of Sr–Nd–Pb Isotopic Ratios of Rock Reference Materials Using Column Separation Techniques and TIMS." Separations 8, no. 11 (November 10, 2021): 213. http://dx.doi.org/10.3390/separations8110213.
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Thermal ionization mass spectrometry (TIMS) can provide highly accurate strontium (Sr), neodymium (Nd), and lead (Pb) isotope measurements for geological and environmental samples. Traces of these isotopes are useful for understanding crustal reworking and growth. In this study, we conducted a sequential separation of Sr, Nd, and Pb and subsequently measured the 87Sr/86Sr, 143Nd/144Nd, 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios of 13 widely used rock certified reference materials (CRMs), namely BCR-2, BHVO-2, GSP-2, JG-1a, HISS-1, JLk-1, JSd-1, JSd-2, JSd-3, LKSD-1, MAG-1, SGR-1, and 4353A, using TIMS. In particular, we reported the first isotopic ratios of Sr, Nd, and Pb in 4353A, Sr and Nd in HISS-1 and SGR-1, and Sr in JLk-1, JSd-2, JSd-3, and LKSD-1. The Sr–Nd–Pb isotopic compositions of most in-house CRMs were indistinguishable from previously reported values, although the Sr and Pb isotopic ratios of GSP-2, JSd-2, JSd-3, and LKSD-1 obtained in different aliquots and/or batches varied slightly. Hence, these rock reference materials can be used for monitoring the sample accuracy and assessing the quality of Sr–Nd–Pb isotope analyses.
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Viehmann, Sebastian. "Hf-Nd Isotopes in Archean Marine Chemical Sediments: Implications for the Geodynamical History of Early Earth and Its Impact on Earliest Marine Habitats." Geosciences 8, no. 7 (July 16, 2018): 263. http://dx.doi.org/10.3390/geosciences8070263.
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The Hf-Nd isotope systems are coupled in magmatic systems, but incongruent Hf weathering (‘zircon effect’) of the continental crust leads to a decoupling of the Hf-Nd isotope systems in low-temperature environments during weathering and erosion processes. The Hf-Nd isotope record was recently dated back from the Cenozoic oceans until the Archean, showing that both isotope systems were already decoupled in seawater 2.7 Ga ago and potentially 3.4 Ga and 3.7 Ga ago. While there might have existed a hydrothermal pathway for Hf into Archean seawater, incongruent Hf weathering of more evolved, zircon-bearing uppermost continental crust that was emerged and available for subaerial weathering accounts for a significant decoupling of Hf-Nd isotopes in the dissolved (<0.2 µm) and suspended (>0.2 µm) fractions of Early Earth’s seawater. These findings contradict the consensus that uppermost Archean continental crust was (ultra)mafic in composition and predominantly submerged. Hence, Hf-Nd isotopes in Archean marine chemical sediments provide the unique potential for future research to trace the emergence of evolved continental crust, which in turn has major implications for the geodynamical evolution of Early Earth and the nutrient flux into the earliest marine habitats on Earth.
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Abbott, April N., Brian A. Haley, Aradhna K. Tripati, and Martin Frank. "Constraints on ocean circulation at the Paleocene–Eocene Thermal Maximum from neodymium isotopes." Climate of the Past 12, no. 4 (April 7, 2016): 837–47. http://dx.doi.org/10.5194/cp-12-837-2016.
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Abstract. Global warming during the Paleocene–Eocene Thermal Maximum (PETM) ∼ 55 million years ago (Ma) coincided with a massive release of carbon to the ocean–atmosphere system, as indicated by carbon isotopic data. Previous studies have argued for a role of changing ocean circulation, possibly as a trigger or response to climatic changes. We use neodymium (Nd) isotopic data to reconstruct short high-resolution records of deep-water circulation across the PETM. These records are derived by reductively leaching sediments from seven globally distributed sites to reconstruct past deep-ocean circulation across the PETM. The Nd data for the leachates are interpreted to be consistent with previous studies that have used fish teeth Nd isotopes and benthic foraminiferal δ13C to constrain regions of convection. There is some evidence from combining Nd isotope and δ13C records that the three major ocean basins may not have had substantial exchanges of deep waters. If the isotopic data are interpreted within this framework, then the observed pattern may be explained if the strength of overturning in each basin varied distinctly over the PETM, resulting in differences in deep-water aging gradients between basins. Results are consistent with published interpretations from proxy data and model simulations that suggest modulation of overturning circulation had an important role for initiation and recovery of the ocean–atmosphere system associated with the PETM.
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PE-PIPER, GEORGIA, and DAVID J. W. PIPER. "Late Cenozoic, post-collisional Aegean igneous rocks: Nd, Pb and Sr isotopic constraints on petrogenetic and tectonic models." Geological Magazine 138, no. 6 (November 2001): 653–68. http://dx.doi.org/10.1017/s0016756801005957.
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Nd isotopic composition has been determined for 16 igneous rocks, representing the wide geochemical, spatial and temporal range of post-collisional, late Cenozoic magmas in the Aegean area. Nd isotopes are used to further interpret previously published Pb and Sr isotope data. The overall pattern of late Cenozoic volcanism resulted from rapid extension, with thermal effects causing melting of hydrated, enriched, subcontinental lithosphere to produce widespread K-rich magmas. Slab break-off and intrusion of hot asthenosphere caused partial melting of rift-related continental margin basalts at the detachment point to generate adakitic magmas. Further outboard, mafic magma from enriched lithospheric mantle melted thickened lower crust to produce the granitoid plutons of the Cyclades. Nd isotopic variation in these varied rock types correlates with pre-Cenozoic palaeo-geography. Proterozoic subduction-related enrichment in Th and U, together with other large-ion lithophile elements, produced distinctive Pb isotope composition. This was later modified where Mesozoic subduction of terrigenous sediment was important, whereas subduction of oceanic carbonate sediments produced enrichment in radiogenic Sr and low Ce/Sr ratios. Late Cenozoic magmas sourced in eastern Pelagonian zone sub-continental lithospheric mantle have Nd model ages of about 1.0 Ga, and generally high 87Sr/86Sr and high 207Pb/204Pb (∼ 15.68) and 208Pb/204Pb (∼ 39.0) for low 206Pb/204Pb (∼ 18.6), but rocks to the west have more radiogenic Pb and higher Ce/Sr as a result of greater subduction of terrigenous sediment from the northern Pindos ocean. Magmas sourced from sub-continental lithosphere beneath the Apulian continental block were strongly influenced by subduction of oceanic crust and sediments north of the passive margin of north Africa. Subduction of Nile-derived terrigenous sediment in the east resulted in Nd model ages of 0.7 to 0.8 Ga and radiogenic Pb isotopes. Greater subduction of oceanic carbonate in the west resulted in magmas with higher 87Sr/86Sr and lower Ce/Sr. The strongly negative εNd for adakites in the central Aegean rules out a source from subducted oceanic basalt, and the adakite magma was probably derived from melting of hydrated Triassic sub-alkaline basalt of continental origin. Where trachytic rocks are succeeded by nepheline-normative basalts (e.g. Samos), Nd isotope data imply that early partial melting of the enriched subcontinental lithospheric mantle involved hydrous amphibole and phlogopite, but once these minerals were consumed, younger magmas were produced by partial melting dominated by olivine and orthopyroxene.
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Zhang, Bang-Lu, Zhi-Cheng Lv, Zhi-Guo Dong, Xin Zhang, Xiao-Fei Yu, Yong-Sheng Li, Shi-Min Zhen, and Chang-Le Wang. "Source Characteristics of the Carboniferous Ortokarnash Manganese Deposit in the Western Kunlun Mountains." Minerals 12, no. 7 (June 21, 2022): 786. http://dx.doi.org/10.3390/min12070786.
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The specific source of ancient sedimentary manganese (Mn) deposits is commonly complex. Here we use systematic major and trace element data with strontium (Sr) and neodymium (Nd) isotopic analyses of the Ortokarnash Mn(II) carbonate ores and associated carbonate rocks from the Upper Carboniferous Kalaatehe Formation (ca. 320 Ma) in order to constrain the Mn source. This formation consists of three members: the first member is a volcanic breccia limestone, the second member is a sandy limestone, and the third member is a black marlstone with the Mn(II) carbonate interlayers. Petrographic observations in combination with low Al2O3 (<3.0 wt%) and Hf (<0.40 ppm) contents and the lack of correlations between the Al2O3 and 87Sr/86Sr ratios as well as εNd(t) values demonstrate a negligible influence of terrigenous detrital contamination on both Sr and Nd isotopic compositions of the Mn(II) carbonate ores. The Sr isotopes of Mn(II) carbonate ores are most likely affected by post-depositional alteration, while Nd isotopes remain unaltered. The initial 87Sr/86Sr ratios in the associated carbonate rocks are likely the result of a mixture of the chemical components (i.e., seawater) and the Al-rich components (e.g., volcanoclastic material), while the detrital effects on Nd isotopes are negligible. In addition, both Sr and Nd isotopes in these non-mineralized wall rocks remained unchanged during post-depositional processes. The relatively low Th/Sc ratios and positive εNd(t) values suggest that the aluminosilicate fraction in the calcarenite and sandy limestone was mainly derived from the weathering of a depleted mafic source, representing the riverine input into the seawater. Given that the Mn(II) carbonate ores are characterized by negative εNd(t) values, these suggest that seafloor-vented hydrothermal fluids derived from interaction with the underlying old continental crust mainly contribute to the source of the Mn(II) carbonates.
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Qasim, Hussein N., and Falih H. Al-Khudair. "Structure of the low-lying positive and negative parity states in even–even 144−154Nd isotopes." International Journal of Modern Physics E 28, no. 12 (December 2019): 1950107. http://dx.doi.org/10.1142/s0218301319501076.
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The low-lying positive and negative parity states of even–even [Formula: see text]Nd isotopes are studied using the interacting boson model (IBM). The negative parity states are involved within the IBM model by adding a single angular momentum ([Formula: see text]) boson with intrinsic negative parity [Formula: see text]-boson to [Formula: see text] and [Formula: see text]-bosons model space. For these nuclei, the potential energy surfaces [Formula: see text], transition probability [Formula: see text], [Formula: see text] and [Formula: see text] are calculated. Phase transition from the [Formula: see text] limit to the [Formula: see text] limit is observed in the chain and the critical point has been determined for [Formula: see text]Nd isotope. It is found that the calculated positive and negative parity energy spectra of Nd-isotopes agree well with the experimental data.
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Robinson, Suzanne, Ruza F. Ivanovic, Lauren J. Gregoire, Julia Tindall, Tina van de Flierdt, Yves Plancherel, Frerk Pöppelmeier, Kazuyo Tachikawa, and Paul J. Valdes. "Simulating marine neodymium isotope distributions using Nd v1.0 coupled to the ocean component of the FAMOUS–MOSES1 climate model: sensitivities to reversible scavenging efficiency and benthic source distributions." Geoscientific Model Development 16, no. 4 (February 22, 2023): 1231–64. http://dx.doi.org/10.5194/gmd-16-1231-2023.
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Abstract. The neodymium (Nd) isotopic composition of seawater is a widely used ocean circulation tracer. However, uncertainty in quantifying the global ocean Nd budget, particularly constraining elusive non-conservative processes, remains a major challenge. A substantial increase in modern seawater Nd measurements from the GEOTRACES programme, coupled with recent hypotheses that a seafloor-wide benthic Nd flux to the ocean may govern global Nd isotope distributions (εNd), presents an opportunity to develop a new scheme specifically designed to test these paradigms. Here, we present the implementation of Nd isotopes (143Nd and 144Nd) into the ocean component of the FAMOUS coupled atmosphere–ocean general circulation model (Nd v1.0), a tool which can be widely used for simulating complex feedbacks between different Earth system processes on decadal to multi-millennial timescales. Using an equilibrium pre-industrial simulation tuned to represent the large-scale Atlantic Ocean circulation, we perform a series of sensitivity tests evaluating the new Nd isotope scheme. We investigate how Nd source and sink and cycling parameters govern global marine εNd distributions and provide an updated compilation of 6048 Nd concentrations and 3278 εNd measurements to assess model performance. Our findings support the notions that reversible scavenging is a key process for enhancing the Atlantic–Pacific basinal εNd gradient and is capable of driving the observed increase in Nd concentration along the global circulation pathway. A benthic flux represents a major source of Nd to the deep ocean. However, model–data disparities in the North Pacific highlight that under a uniform benthic flux, the source of εNd from seafloor sediments is too non-radiogenic in our model to be able to accurately represent seawater measurements. Additionally, model–data mismatch in the northern North Atlantic alludes to the possibility of preferential contributions from “reactive” non-radiogenic detrital sediments. The new Nd isotope scheme forms an excellent tool for exploring global marine Nd cycling and the interplay between climatic and oceanographic conditions under both modern and palaeoceanographic contexts.
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Bonev, Nikolay, Zornitsa Dotseva, and Massimo Chiaradia. "Comparative Nd-Sr-Pb isotopes geochemistry of the eastern Circum-Rhodope belt ophiolitic mafic suites, Greece-Bulgaria." Review of the Bulgarian Geological Society 83, no. 3 (December 2022): 69–72. http://dx.doi.org/10.52215/rev.bgs.2022.83.3.69.
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We report on the isotopic compositions of the Jurassic supra-subduction zone Evros ophiolite mafic rocks exposed in the eastern Circum-Rhodope Belt in the Thrace region of northeastern Greece. These mafic units consist of low-Ti gabbroic and basaltic rocks, which Nd-Sr-Pb isotopes are compatible with dominant mantle-derived Mid-Ocean Ridge Basalt (MORB) component mixed with a detectable amount of crustal material and/or sediment involved in their melt source in the subduction zone. These isotopic features are consistent with an intra-oceanic arc origin of the mafic ophiolite rocks, and the Evros ophiolite Nd and Pb isotopes are comparable to those of the counterpart mafic rocks from the Mandritsa Unit in the eastern Rhodope Massif of southern Bulgaria.
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Gudelius, Dominik, Sonja Aulbach, Hans-Michael Seitz, and Roberto Braga. "Crustal fluids cause strong Lu-Hf fractionation and Hf-Nd-Li isotopic provinciality in the mantle of continental subduction zones." Geology 50, no. 2 (November 2, 2021): 163–68. http://dx.doi.org/10.1130/g49317.1.
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Abstract Metasomatized mantle wedge peridotites exhumed within high-pressure terranes of continental collision zones provide unique insights into crust-mantle interaction and attendant mass transfer, which are critical to our understanding of terrestrial element cycles. Such peridotites occur in high-grade gneisses of the Ulten Zone in the European Alps and record metasomatism by crustal fluids at 330 Ma and high-pressure conditions (2.0 GPa, 850 °C) that caused a transition from coarse-grained, garnet-bearing to fine-grained, amphibole-rich rocks. We explored the effects of crustal fluids on canonically robust Lu-Hf peridotite isotope signatures in comparison with fluid-sensitive trace elements and Nd-Li isotopes. Notably, we found that a Lu-Hf pseudo-isochron is created by a decrease in bulk-rock 176Lu/177Hf from coarse- to fine-grained peridotite that is demonstrably caused by heavy rare earth element (HREE) loss during fluid-assisted, garnet-consuming, amphibole-forming reactions accompanied by enrichment in fluid-mobile elements and the addition of unradiogenic Nd. Despite close spatial relationships, some peridotite lenses record more intense fluid activity that causes complete garnet breakdown and high field strength element (HFSE) addition along with the addition of crust-derived unradiogenic Hf, as well as distinct chromatographic light REE (LREE) fractionation. We suggest that the observed geochemical and isotopic provinciality between peridotite lenses reflects different positions relative to the crustal fluid source at depth. This interpretation is supported by Li isotopes: inferred proximal peridotites show light δ7Li due to strong kinetic Li isotope fractionation (−4.7–2.0‰) that accompanies Li enrichment, whereas distal peridotites show Li contents and δ7Li similar to those of the depleted mantle (1.0–7.2‰). Thus, Earth's mantle can acquire significant Hf-Nd-Li-isotopic heterogeneity during locally variable ingress of crustal fluids in continental subduction zones.
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Lattoofi, Nabeel F., and Ali A. Alzubadi. "Study of giant dipole resonances for neodymium isotopes with an exciton model." International Journal of Modern Physics E 29, no. 10 (October 2020): 2050084. http://dx.doi.org/10.1142/s0218301320500846.
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The partial photonuclear [Formula: see text], pn) and [Formula: see text] and the total photonuclear cross-sections (the giant dipole resonance (GDR)) have been investigated theoretically for neodymium isotopes, namely [Formula: see text]Nd, using framework of the EMPIRE 3.2.2 code. The energy, width and cross-section parameters of the GDR used in our calculations have been investigated in this paper depending on the deformation parameters of nuclei. The calculated results have been compared with the experimental data and with those calculated using Lorentzian fitting parameters. Our calculations show a good agreement for all isotopes under study and give better results than the results calculated with Lorentzian parameters. Furthermore, the neutron number dependence of the total and partial photonuclear cross-sections has also been discussed. The results appear that the EMPIRE code used is a perfect tool for reproducing the splitting in the GDR for deformed [Formula: see text]Nd isotope in two distinct dipole modes which are perfectly consistent with the experimental results. It has also been shown that the present parameters are suitable parameters for reproducing the GDR for spherical, or nearly spherical, and the deformed ([Formula: see text]Nd) neodymium isotopes. The parameters have been indicating the small deformation in [Formula: see text]Nd, which cannot be shown by the Lorentzian fitting parameters.
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Alatarvas, Raisa, Ninna Immonen, and Kari Strand. "Clay mineral and Nd, Pb, and Sr isotope provenance of a MIS 4-3 sediment record from the Lomonosov Ridge, central Arctic Ocean." Bulletin of the Geological Society of Finland 95, no. 1 (June 22, 2023): 35–46. http://dx.doi.org/10.17741/bgsf/95.1.003.
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Modern techniques for detrital mineral provenance were applied to sediment core 96/12-1pc from the Lomonosov Ridge in the central Arctic Ocean. The techniques include quantitative clay mineralogy analysis combined with determination of Nd, Pb, and Sr isotopes from clay fraction. The clay mineral assemblage and the isotope signatures depict distinct changes during the Marine Isotope Stage (MIS) 4-3 transition corresponding to the Middle Weichselian deglaciation. This transition is characterised by a homogenous, 48 cm thick, dark grey, silty clay layer with a distinctive IRD concentration, forming a prominent marker bed for the central Arctic Ocean sediments. The elevated smectite and kaolinite contents in the transitional interval are possible weathering products of the Siberian basaltic rocks, such as the Putorana Plateau, feeding the shelves of the Kara Sea and the western Laptev Sea. The Nd and Sr isotope values are compatible with input from the basaltic rocks and fall within the isotopic range of sediments from these shelves. The abrupt changes in the Nd, Pb and Sr isotopic data from the distinct grey layer attributed to the MIS 4-3 transition likely mark a pronounced deglaciation event. An increase in coarse debris in the grey layer indicates a change in the sedimentation regime with a strong iceberg rafting component. This change may also be related to a sudden release of meltwater from a large ice-dammed lake in the northern Siberia.
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Kay, R. W., J. L. Rubenstone, and S. Mahlburg Kay. "Aleutian terranes from Nd isotopes." Nature 322, no. 6080 (August 1986): 605–9. http://dx.doi.org/10.1038/322605a0.
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Nasef, Dalenda, Najat S. Eshaftri Eshaftri, Ayad Ezwam Ezwam, Suad M. Bogrin Bogrin, Asma A. Elbendag Elbendag, and Sadiq M. El-kadi El-kadia. "Structural evolution in 146–158 Nd isotopes using IBM-2 Hamiltonian." Journal of Pure & Applied Sciences 20, no. 2 (December 15, 2021): 171–75. http://dx.doi.org/10.51984/jopas.v20i2.1597.
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Neodymium isotopes (Z=60) lie in the traditional rotational to transitional-spherical region that occurs at the range of deformed nuclei. The identity of 146−158 Neodymium nuclei have been determined in framework of Interacting Boson Model-2, a simulation program with NPBOS has been built to obtain the theoretical energy levels for Neodymium isotopes. The parameters of the best fit to the measured data are determined.
The energy positive parity bands of those isotopes were calculated using (IBM-2) and then it compared with the experimental values. The mentioned isotopes ratios have calculated and also E-GOS curves ) have drawn as a function of the spin I, to classify symmetry of the nuclei. The electromagnetic transition probabilities B(E2) of these nuclei was calculated as well, where a good agreement for low lying energy states were obtained between experimental results and theoretical calculations.
The results have been shown that the interested nuclei 152-158Nd have rotational characters SU (3), and O (6) symmetry is substantiated for 146-148Nd, as well as the critical point X (5) has been determined for 150Nd isotope.
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SHENG, ZONG-QIANG, and JIAN-YOU GUO. "SYSTEMATIC ANALYSIS OF CRITICAL POINT NUCLEI IN THE RARE-EARTH REGION WITH RELATIVISTIC MEAN FIELD THEORY." Modern Physics Letters A 20, no. 35 (November 20, 2005): 2711–21. http://dx.doi.org/10.1142/s0217732305017883.
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The shape phase transition between spherical U (5) and axially deformed SU (3) nuclei is investigated systemically for the rare-earth region nuclei by the constrained relativistic mean field theory with the interactions NL3. The properties of ground state for Nd , Gd and Dy isotopes are described fairly well as compared with experiments. By examining the potential energy curve and quadruple deformation β2 obtained with this microscopic approach, the possible critical point nuclei are suggested to be 148,150 Nd for Nd isotopes, but 148 Nd is the best candidate, and 150 Nd is slightly to the rotor side of the phase transition. For Gd and Dy isotopes, 150,152 Gd and 152,154 Dy are suggested to be the critical point nuclei. Similar conclusions are also drawn from the microscopic neutron single particle spectra.
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Rosner, S. D., D. Masterman, T. J. Scholl, and R. A. Holt. "Measurement of hyperfine structure and isotope shifts in Nd II." Canadian Journal of Physics 83, no. 8 (August 1, 2005): 841–54. http://dx.doi.org/10.1139/p05-029.
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The high-resolution spectra of 110 transitions in Nd II over the range 418465 nm were observed using the collinear fast-ion-beam/laser method (FIBLAS). The lower states of these transitions include the ground state and 10 metastable even-parity states with energies up to 5986 cm1. The 64 odd-parity upper states have energies up to 29 434 cm1. For each transition isotope shifts were measured for all the stable isotopes (mass numbers 142, 143, 144, 145, 146, 148, and 150), as well as hyperfine parameters for the two odd-mass-number isotopes. These quantities are important in modeling profiles of absorption lines in stellar atmospheres to obtain abundances, and in the classification of atomic energy levels. PACS Nos.: 31.30.Gs, 32.10.Fn, 95.30.Ky
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Sun, Xiang, Yongjun Lu, Qiang Li, and Ruyue Li. "A Downgoing Indian Lithosphere Control on Along-Strike Variability of Porphyry Mineralization in the Gangdese Belt of Southern Tibet." Economic Geology 116, no. 1 (November 23, 2020): 29–46. http://dx.doi.org/10.5382/econgeo.4768.
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Abstract The E-trending Gangdese porphyry copper belt in southern Tibet is a classic example of porphyry mineralization in a continental collision zone. New zircon U-Pb geochronological, zircon Hf-O, and bulk-rock Sr-Nd isotope data for the Miocene mineralizing intrusions from the Qulong, Zhunuo, Jiru, Chongjiang, and Lakange porphyry copper deposits and Eocene igneous rocks from the western Gangdese belt, together with literature data, show that both Paleocene-Eocene igneous rocks and Miocene granitoids exhibit coupled along-arc isotopic variations, characterized by bulk-rock ɛNd(t) and zircon ɛHf(t) values increasing from ~84° to ~92°E and then decreasing toward ~95°E. These are interpreted to reflect increasing contributions of subducted Indian continental materials from ~92° to ~84°E and from ~92° to ~95°E, respectively. The Miocene mineralizing intrusions were derived from subduction-modified Tibetan lower crust represented isotopically by the Paleocene-Eocene intrusions, with contributions from Indian plate-released fluids and mafic melts derived from mantle metasomatized by subducted Indian continental materials. Involvement of isotopically ancient Indian continental materials increased from east (Qulong) to west (Zhunuo), which is interpreted to reflect an increasingly shallower angle of the downgoing Indian slab from east to west, consistent with geophysical imaging. Exploration of Gangdese Miocene porphyry copper deposits should focus on the Paleocene-Eocene arc where the subarc mantle was mainly enriched by fluids from the subducted Neo-Tethyan oceanic slab. Neodymium-Hf isotope data for mineralizing igneous rocks from porphyry copper deposits globally show no obvious correlations with Cu endowment. Although Nd-Hf isotopes are useful for imaging lithospheric architecture through time, caution must be taken when using Nd-Hf isotopes to evaluate the potential endowment of porphyry copper deposits, because other factors such as tectonic setting, crustal thickening, magma differentiation, fluid exsolution, and ore-forming processes all play roles in determining Cu endowments and grades.
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Jin, Luying, Kezhang Qin, Guangming Li, Junxing Zhao, Zhenzhen Li, Zhuyin Chu, and Guoxue Song. "Formation of the Chalukou High Fluorine-Type Mo (–Zn–Pb) Deposit, NE China: Constraints from Fluorite and Sphalerite Rare Earth Elements and Sr–Nd Isotope Compositions." Minerals 13, no. 1 (January 3, 2023): 77. http://dx.doi.org/10.3390/min13010077.
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Fluorite is a widespread mineral in porphyry and hydrothermal vein Mo-polymetallic deposits. Here, fluorite is utilised as a probe to trace the fluid source and reveal the fluid evolution process in the Chalukou giant Mo (Pb‒Zn) deposit, Northeast China, which is characterised as early porphyry Mo and later vein-style Zn–Pb mineralisation. A detailed rare earth element (REE) and Sr–Nd isotope study of fluorite combined with Sr isotopes of sphalerite is conducted for the Chalukou deposit. The chondrite-normalised REE patterns of fluorites from molybdenite veins show light REE (LREE)-enriched patterns, with negative Eu anomalies (δEu = 0.60) and weakly negative Y anomalies (Y/Y* = 0.72). The fluorites associated with sphalerite veins exhibit rare earth element (REE)-flat patterns with negative Eu anomalies (δEu = 0.65 to 0.99) and positive Y anomalies (Y/Y* = 1.37 to 3.08). In addition, during the progression from Mo to Zn–Pb mineralisation, the total concentration of REEs decreases from 839 ppm to 53.7 ppm, and Y/Ho ratios increase from 22.1 to 92.5. These features may be explained by the different mobilities of REE complexes during fluid migration. The Eu anomalies are considered to be inherited from source fluids. All the initial 87Sr/86Sr ratios of fluorite and sphalerite are between those of ore-forming porphyries and wall rocks (rhyolite), with fluorite ratios ranging from 0.706942 to 0.707386 and sphalerite ratios varying from 0.705221 to 0.710417. The majority of εNd(t) values of fluorite varying from −6.4 to −3.6 are also located between the ratios exhibited by ore-forming porphyries and rhyolite, whereas three εNd(t) values of fluorites ranging from −0.26 to 0.36 are close to those of ore-forming porphyries. All the isotopic features indicate that the Sr-Nd isotope ratios of hydrothermal fluid are derived from porphyries and disturbed by fluid–rock reactions. Together with a two-stage Sr–Nd isotope mixing model, we suggest that different sources and fluid‒rock interactions (syn-ore intrusions and strata) finally influence the Sr–Nd isotopes of the ore-forming fluids, which are recorded by the majority of fluorite and sphalerite.
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Ouhachi, M., M. R. Oudih, M. Fellah, and N. H. Allal. "Nuclear structure and decay properties of Nd isotopes." International Journal of Modern Physics E 27, no. 07 (July 2018): 1850059. http://dx.doi.org/10.1142/s0218301318500593.
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Using the Hartree–Fock–Bogoliubov mean-field theory, the ground-state structural and decay properties of Nd isotopes are investigated from the proton-rich side up to the neutron drip-line. Quantities such as binding energies per nucleon, one and two-neutron separation energies, rms charge radii, and quadrupole deformation parameters have been calculated. Compared with the relativistic mean-field results, the present calculations are in better agreement with the available experimental data. The results show clearly the signature of a shape transition at [Formula: see text] and an abrupt increase in the deformation near the neutron drip-line. Further, the possible decay modes like alpha, cluster and [Formula: see text]-decay are analyzed in a unified fission model and phenomenological formulas. Overall, a good agreement is achieved between the calculated and experimental [Formula: see text]-values and half-lives wherever available. The most likely decay modes are thus identified throughout the isotopic chain.
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Hindshaw, Ruth S., Nicholas J. Tosca, Alexander M. Piotrowski, and Edward T. Tipper. "Clay mineralogy, strontium and neodymium isotope ratios in the sediments of two High Arctic catchments (Svalbard)." Earth Surface Dynamics 6, no. 1 (March 5, 2018): 141–61. http://dx.doi.org/10.5194/esurf-6-141-2018.
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Abstract. The identification of sediment sources to the ocean is a prerequisite to using marine sediment cores to extract information on past climate and ocean circulation. Sr and Nd isotopes are classical tools with which to trace source provenance. Despite considerable interest in the Arctic Ocean, the circum-Arctic source regions are poorly characterised in terms of their Sr and Nd isotopic compositions. In this study we present Sr and Nd isotope data from the Paleogene Central Basin sediments of Svalbard, including the first published data of stream suspended sediments from Svalbard. The stream suspended sediments exhibit considerable isotopic variation (εNd = −20.6 to −13.4; 87Sr ∕ 86Sr = 0.73421 to 0.74704) which can be related to the depositional history of the sedimentary formations from which they are derived. In combination with analysis of the clay mineralogy of catchment rocks and sediments, we suggest that the Central Basin sedimentary rocks were derived from two sources. One source is Proterozoic sediments derived from Greenlandic basement rocks which are rich in illite and have high 87Sr ∕ 86Sr and low εNd values. The second source is Carboniferous to Jurassic sediments derived from Siberian basalts which are rich in smectite and have low 87Sr ∕ 86Sr and high εNd values. Due to a change in depositional conditions throughout the Paleogene (from deep sea to continental) the relative proportions of these two sources vary in the Central Basin formations. The modern stream suspended sediment isotopic composition is then controlled by modern processes, in particular glaciation, which determines the present-day exposure of the formations and therefore the relative contribution of each formation to the stream suspended sediment load. This study demonstrates that the Nd isotopic composition of stream suspended sediments exhibits seasonal variation, which likely mirrors longer-term hydrological changes, with implications for source provenance studies based on fixed end-members through time.
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Li, Yihong, Shanshan Wang, Yu Yan, Jinpei Yan, Ruilian Yu, and Gongren Hu. "Characteristics and Provenance Implications of Rare Earth Elements and Nd Isotope in PM2.5 in a Coastal City of Southeastern China." Atmosphere 13, no. 9 (August 26, 2022): 1367. http://dx.doi.org/10.3390/atmos13091367.
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The source apportionment of fine particulate matters, especially PM2.5, has drawn great attention worldwide. Since rare earth elements (REEs) and Nd isotopes can serve as source tracers, in this study, the characteristics and provenance implications of REEs and Nd isotopes in PM2.5 of four seasons in Xiamen city, China, were investigated. The range of the ratios of ΣREE to PM2.5 was 1.04 × 10−5 to 8.06 × 10−4, and the mean concentration of REEs in PM2.5 were in the order of spring > autumn > winter > summer. According to the geoaccumulation index (Igeo), spring was the season in which anthropogenic sources had the greatest impact on the REEs in PM2.5. The chondrite-normalized REE distribution patterns exhibited light rare earth elements (LREEs, including La, Ce, Pr, Nd, Pm, Sm and Eu) enrichment and a flat heavy rare earth elements (HREEs, including Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) pattern. Significant negative Eu anomalies and no significant Ce anomalies were observed in the PM2.5. The results of La-Ce-Sm ternary plots indicated that the REEs in the PM2.5 might be related to both natural and anthropogenic sources. Combined with the Nd isotope, the 143Nd/144Nd versus Ce/Ce* plot further illustrated that the REEs in the PM2.5 seemed to mostly originate from multiple potential sources, in which vehicle exhaust emissions, coal burning and cement dust made a great contribution to REEs in PM2.5.
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Kriswarini, Rosika, Noviarty Noviarty, Erlina Noerpitasari, and Arif Nugroho. "Effect of CsNO<sub>3</sub> on Neodymium (Nd) and Cesium (Cs) Recovery in Nuclear Fuel Using Precipitation Method." Materials Science Forum 1093 (July 21, 2023): 127–32. http://dx.doi.org/10.4028/p-pyz39c.
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The addition of CsNO3 against Nd and Cs recovery in nuclear fuel using the precipitation method has been carried out. Precipitation methods have been carried out by previous researchers to separate cesium in U3Si2/Al and UMo/Al nuclear fuels. The recovery of cesium in the nuclear fuel obtained was more than 95%. After got optimal recovery for Cs separation, in this research would use the method for Nd separation. Beside the Cs isotope, the Nd isotope was the result of fission product after the radiation process of nuclear fuel in nuclear reactor. Both isotopes were used as burn-up indicators. To obtain optimal Nd recovery, in the separation process using the precipitation method, weight various CsNO3 are added. CsNO3 as a carrier in this method. The nuclear fuel solution containing Nd was added 100, 200, 400, 600 and 1000 mg of CsNO3. Then the mixed solution was added 4 mL of HClO4 and cooled at 0oC using an ice bath for 1 hour. A precipitate would form after cooling process for 1 hour. The liquid phase was separated from the solid phase. Then Nd and Cs in the liquid phase were analyzed using XRF. The analysis results of the Nd content in the liquid phase showed that the optimal recovery was 94.21% with the addition of 200 mg of CsNO3. While most of the Cs is in the solid phase with recovery greater than 99% on the addition of CsNO3 between 100-1000 mg.
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Falloon, Trevor J., Kaj Hoernle, Bruce F. Schaefer, Ilya N. Bindeman, Stanley R. Hart, Dieter Garbe-Schonberg, and Robert A. Duncan. "Petrogenesis of Lava from Christmas Island, Northeast Indian Ocean: Implications for the Nature of Recycled Components in Non-Plume Intraplate Settings." Geosciences 12, no. 3 (March 3, 2022): 118. http://dx.doi.org/10.3390/geosciences12030118.
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Lava samples from the Christmas Island Seamount Province (CHRISP) record an extreme range in enriched mantle (EM) type Sr-Nd-Pb-Hf isotope signatures. Here we report osmium isotope data obtained on four samples from the youngest, Pliocene petit-spot phase (Upper Volcanic Series, UVS; ~4.4 Ma), and four samples from the earlier, Eocene (Lower Volcanic Series, LVS; ~40 Ma) shield building phase of Christmas Island. Osmium concentrations are low (5–82 ppt) with initial Os isotopic values (187Os/188Osi) ranging from (0.1230–0.1679). Along with additional new geochemical data (major and trace elements, Sr-Nd-Pb isotopes, olivine δ18O values), we demonstrate the following: (1) The UVS is consistent with melting of shallow Indian mid-ocean ridge basalt (MORB) mantle enriched with both lower continental crust (LCC) and subcontinental lithospheric mantle (SCLM) components; and (2) The LVS is consistent with recycling of SCLM components related to Gondwana break-up. The SCLM component has FOZO or HIMU like characteristics. One of the LVS samples has less radiogenic Os (γOs –3.4) and provides evidence for the presence of ancient SCLM in the source. The geochemistry of the Christmas Island lava series supports the idea that continental breakup causes shallow recycling of lithospheric and lower crustal components into the ambient MORB mantle.
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Santhosh, K. P., R. K. Biju, Sabina Sahadevan, and Antony Joseph. "Exotic decay in proton-rich Nd isotopes." Physica Scripta 77, no. 6 (June 2008): 065201. http://dx.doi.org/10.1088/0031-8949/77/06/065201.
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Buck, B., A. C. Merchant, and S. M. Perez. "Exotic clustering in Ce and Nd isotopes." Nuclear Physics A 657, no. 3 (September 1999): 267–79. http://dx.doi.org/10.1016/s0375-9474(99)00342-5.
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Pe-Piper, Georgia, and David JW Piper. "Geochemical evolution of Devonian-Carboniferous igneous rocks of the Magdalen basin, Eastern Canada: Pb- and Nd-isotope evidence for mantle and lower crustal sources." Canadian Journal of Earth Sciences 35, no. 3 (March 1, 1998): 201–21. http://dx.doi.org/10.1139/e97-106.
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Magmatism associated with the extensional Magdalen basin includes voluminous tholeiitic gabbro and basalt and local granite and rhyolite. Pb- and (or) Nd-isotope determinations have been made on 70 igneous rocks from throughout the basin, and a further 15 samples of Avalonian basement from the southern margin of the basin, to characterize the contribution of lower crustal blocks and mantle sources to the magmatism and to constrain tectonic models for the basin. Five phases of magmatic evolution are distinguished in the Magdalen basin. (1) Middle to Late Devonian partial melting of lithospheric mantle, producing principally tholeiites and minor alkalic basalt. Tholeiites have Pb isotopic compositions similar to that of younger Triassic tholeiites generated from the same mantle, but experienced less crustal contamination. Regional variations in trace element composition of the mantle can be recognized. (2) The mafic magma triggered anhydrous base-of-crust melting, principally along the transpressive Cobequid and Rockland Brook faults, producing A-type granites in which radiogenic Pb increases northeastward. (3) In the latest Devonian, a large base-of-crust fractionating magma chamber evolved. It contained immiscible mafic and minor felsic magma, with uniform Nd isotopes, and high Ti in the mafic magma. (4) Although late Tournaisian dykes are not strongly fractionated, their evolution involved more crustal assimilation than earlier mafic rocks. (5) Local Viséan-Westphalian alkalic magmas, which ascended along crustal-scale faults, have Pb and Nd isotopic compositions resembling mantle plumes or their mixtures with lithospheric mantle sources. Only these youngest rocks show any isotopic evidence for input from an asthenospheric plume source, suggesting that regional extension was responsible for most of the magmatism.
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Huang, Chao, Yue-Heng Yang, Jin-Hui Yang, and Lie-Wen Xie. "In situ simultaneous measurement of Rb–Sr/Sm–Nd or Sm–Nd/Lu–Hf isotopes in natural minerals using laser ablation multi-collector ICP-MS." Journal of Analytical Atomic Spectrometry 30, no. 4 (2015): 994–1000. http://dx.doi.org/10.1039/c4ja00449c.
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This study presents a combined methodology of simultaneously measuring Rb–Sr/Sm–Nd or Sm–Nd/Lu–Hf isotopes in natural minerals by a means of two multiple collector inductively coupled plasma mass spectrometers connected to a 193 nm excimer laser ablation system.
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Linghu, Miaomiao, Zimu Li, Jinfeng Sun, and Jiheng Zhang. "Magma Source and Petrogenesis of the Early Cretaceous Granites in The Liaodong Peninsula: Evidence from In Situ Apatite Sr-Nd and Zircon Hf-O Isotopes." Minerals 13, no. 4 (April 12, 2023): 545. http://dx.doi.org/10.3390/min13040545.
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Apatite Sr-Nd and zircon Hf-O isotopes are broadly used to trace magma sources and constrain magma evolution processes, further improving our understanding of the origin of granitoids. We present zircon U-Pb ages, whole-rock major and trace elements, and whole-rock Sr-Nd-Hf, zircon Hf-O, and apatite Sr-Nd isotopic data for the coarse-grained quartz monzonite, biotite monzogranite, and granite porphyry in the Yushulinzi pluton in the Liaodong Peninsula, the eastern North China Craton, to establish their magma sources and petrogenesis. The coarse-grained quartz monzonite, biotite monzogranite, and granite porphyry were formed contemporaneously, with zircon U-Pb ages of 123–119 Ma. They share enriched whole-rock Sr-Nd-Hf and zircon Hf isotopic compositions, and the coarse-grained quartz monzonite has crust-like δ18O values (5.7–6.7‰). The coarse-grained quartz monzonite and biotite monzogranite have variable apatite (87Sr/86Sr)i ratios and negative apatite εNd(t) values. These isotopic characteristics indicate that the different rock types in the Yushulinzi pluton were derived from the partial melting of ancient crustal material in the North China Craton. Their geochemical and petrographic characteristics indicate that the crystal-melt segregation model can be employed to elucidate the genetic links among different rock types, with the coarse-grained quartz monzonite representing crystal accumulation and the biotite monzogranite and granite porphyry representing interstitial melts extracted from a crystal-rich magma chamber. Furthermore, the variable apatite Sr isotopic compositions and subtle differences in the peak zircon εHf(t) values of the studied rock samples confirm the possibility of a contribution from shallow crustal components and materials with high εHf(t) values during magma evolution, which is not readily revealed by their whole-rock Sr-Nd-Hf isotopic compositions. These results demonstrate that in situ apatite Sr-Nd and zircon Hf-O isotopic analyses have the potential to provide distinctive insights into the magma sources and evolution of magmatic systems.
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Bédard, L. Paul, and John N. Ludden. "Nd-isotope evolution of Archaean plutonic rocks in southeastern Superior Province." Canadian Journal of Earth Sciences 34, no. 3 (March 1, 1997): 286–98. http://dx.doi.org/10.1139/e17-026.
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The Opatica plutonic belt, Abitibi greenstone belt, and Pontiac Subprovince represent a major proportion of the southeastern Superior Province, which was formed and accreted rapidly between approximately 2.9 and 2.8 Ga. Plutons in these belts are grouped into four types: (i) trondhjemite–tonalite–granodiorite (TTG) suite (2.82–2.69 Ga), (ii) monzodiorite (MZD) suite (2.697–2.669 Ga), (iii) late alkaline granitoid (ALK) suite (2.68–2.67 Ga), and (iv) anatectic granite and monzonite (ANA) suite (2.69–2.64 Ga). The four suites are represented in all belts and show similar petrography and geochemistry. In terms of Nd-isotope composition, the TTG, MZD, and ALK suites are typical of destructive plate margin magmatism and have + 1.4 < initial εNd < +3.7, values which are very similar to that of the Abitibi mantle (εNd + 2.5). The lower values for the ANA suites (εNd + 0.1 to + 2.4) result from recycling of crustal components. In the Opatica belt the ANA granitoids fall on the Nd-isotope evolution curve defined by the Opatica TTG plutons, and are thus considered to be melt products of this suite. However, Abitibi and Pontiac ANA suites show a larger range of εNd, from + 0.1 to + 2.4, compared with + 1.0 to + 1.3 for the Opatica, suggesting more heterogeneous crustal source rock. Recent geological mapping and geophysical studies associated with the Lithoprobe project have suggested that the Opatica belt represents a plutonic belt against which the Abitibi was accreted by subduction-related collision and that the Pontiac Subprovince is dominated by imbricated metasediments related to the final stages of collision in the Abitibi region. The Nd-isotope data provide support for these arguments. Early plutonic suites are mantle derived and related to arc-accretion processes. As the collision process progresses, a more evolved isotopic component is introduced, possibly in relation to sediment subduction into the mantle. Anatexis of the crust in the central Opatica belt and the core of the Pontiac Subprovince resulted in the formation of granites with a crustal signature for Nd isotopes.
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Huber, Miłosz A., Stanisław Hałas, Yuri N. Neradovsky, Tamara B. Bayanova, Artem W. Mokrushin, and Lesia Lata. "Stable isotope geochemistry of sulfides from intrusion in Monchegorsk, northern part of Baltic Shield." Geochronometria 43, no. 1 (June 1, 2016): 96–101. http://dx.doi.org/10.1515/geochr-2015-0034.
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Abstract The sulfide minerals from old mafic intrusion rocks from the Kola Peninsula were analyzed on stable sulfur isotopes. These samples were already dated by the Sm-Nd method. These sulfide samples were evaluated upon a geochemical composition by ICP-MS. The sulfide mineral samples were selected from the main ore-bearing rocks of the Monchetundra layered intrusion. The analyzed sulfides formed several generations of mineralization associated with primary and hydrothermal stage of formation of the deposits. Isotopic studies confirm a few consecutive stages of mineralization. These data were compared with the results of Sm-Nd dating of sulfide mineralization. The results of geochemical and geochronological studies indicate a complementarity in the context of determining the mineralization stages.
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Abraham, Anne-Claude, Don Francis, and Mireille Polvé. "Origin of Recent alkaline lavas by lithospheric thinning beneath the northern Canadian Cordillera." Canadian Journal of Earth Sciences 42, no. 6 (June 1, 2005): 1073–95. http://dx.doi.org/10.1139/e04-092.
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Recent alkaline lavas that have erupted across the disparate terranes of the northern Canadian Cordillera provide natural probes with which to interrogate the underlying lithosphere. The lavas range between two compositional end members, olivine nephelinite (NEPH) and hypersthene-normative olivine (Hy-NORM) basalt. The chemical signature of amphibole in the incompatible element enriched NEPH end member indicates that it is derived in the lithospheric mantle. The Hy-NORM end member is characterized by lower incompatible trace element contents but is still relatively enriched relative to primitive mantle. Although the Hy-NORM end member is always more radiogenic in Pb and Sr isotopes and less radiogenic in Nd isotopes than the NEPH end member, its isotopic signature varies with tectonic belt. In particular, Hy-NORM basalts in the Omineca Belt are strikingly more radiogenic in Sr and Pb isotopes and less radiogenic in Nd isotopes than otherwise equivalent Hy-NORM basalts in the adjacent Intermontane Belt, indicating the existence of a major lithospheric boundary between the two belts. Cordilleran and other continental Hy-NORM basalts have distinctly low Ca and high Na contents compared with their equivalents in oceanic hot spots or at mid-ocean ridges. A comparison with experimental melts of mantle peridotite indicates that these characteristics reflect smaller degrees of partial melting (<10%) in the stability field of garnet in the lower lithospheric mantle beneath the northern Cordillera. Contrary to the conclusion commonly drawn from experimental results, the Cordilleran NEPH lavas may be derived from similar or shallower depths than coeval Hy-NORM basalts.
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Abbott, A. N., B. A. Haley, A. K. Tripati, and M. Frank. "Constraints on ocean circulation at the Paleocene–Eocene Thermal Maximum from neodymium isotopes." Climate of the Past Discussions 11, no. 3 (June 30, 2015): 2557–83. http://dx.doi.org/10.5194/cpd-11-2557-2015.
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Abstract. Global warming during the Paleocene Eocene Thermal Maximum (PETM) ~55 million years ago (Ma) coincided with a massive release of carbon to the ocean–atmosphere system, as indicated by carbon isotopic data. Previous studies have argued for a role for changing ocean circulation, possibly as a trigger or response to climatic changes. We use neodymium (Nd) isotopic data to reconstruct short high-resolution records of deep-water circulation across the PETM. These records are derived by reductively leaching sediments from seven globally distributed sites and comparing data with published data from fossil fish debris to reconstruct past deep ocean circulation across the PETM. The Nd data for the leachates are interpreted to be consistent with previous studies that have used fish teeth and benthic foraminiferal δ13C to constrain regions of convection. There is some evidence from combining Nd isotope and δ13C records that the three major ocean basins may not have had substantial exchanges of deep waters. If the isotopic data are interpreted within this framework, then the observed pattern may be explained if the strength of overturning in each basin varied distinctly over the PETM, resulting in differences in deep-water aging gradients between basins. Results are consistent with published interpretations from proxy data and model simulations that suggest modulation of overturning circulation had an important role for global recovery of the ocean–atmosphere system after the PETM.
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Speziale, Sergio, Francesca Castorina, Paolo Censi, Celso de Barros Gomes, Leila Soares Marques, and Piero Comin-Chiaramonti. "Carbonatites from the southern Brazilian Platform: A review. II: Isotopic evidences." Open Geosciences 12, no. 1 (August 21, 2020): 678–702. http://dx.doi.org/10.1515/geo-2020-0032.
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AbstractEarly and Late Cretaceous alkaline and alkaline–carbonatitic complexes from southern Brazil are located along the main tectonic lineaments of the South America Platform. Calcium-, magnesium-, and ferrocarbonatites are well represented and frequently associated even in the same complex. Primary carbonates present significant variations in C–O isotopic compositions, which are mainly due to isotope exchange with H2O–CO2-rich hydrothermal fluids, whereas fractional crystallization or liquid immiscibility probably affects the δ18O and δ13C values by no more than 2δ‰. Our isotope exchange model implies that the most significant isotopic variations took place in a hydrothermal environment, e.g., in the range 400–80°C, involving fluids with the CO2/H2O ratio ranging from 0.8 to 1. Sr–Nd–Pb isotope systematics highlight heterogeneous mixtures between HIMU and EMI mantle components, similar to the associated alkaline rocks and the flood tholeiites from southern Brazil. In spite of the strong variation shown by C–O isotopes, Sr–Nd–Pb–Os isotopic systematics could be related to an isotopically enriched source where the chemical heterogeneities reflect a depleted mantle “metasomatized” by small-volume melts and fluids rich in incompatible elements. These fluids are expected to have promoted crystallization of K-rich phases in the mantle, which produced a veined network variously enriched in LILE and LREE. The newly formed veins (enriched component) and peridotite matrix (depleted component) underwent a different isotopic evolution with time as reflected by the carbonatites. These conclusions may be extended to the whole Paraná–Etendeka system, where isotopically distinct parent magmas were generated following two main enrichment events of the subcontinental lithospheric mantle at 2.0–1.4 and 1.0–0.5 Ga, respectively, as also supported by Re–Os systematics. The mantle sources preserved the isotopic heterogeneities over a long time, suggesting a nonconvective lithospheric mantle beneath different cratons or intercratonic regions. Overall, the data indicate that the alkaline–carbonatitic magmatism originated from a locally heterogeneous subcontinental mantle.
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McCoy-West, Alex J., Marc-Alban Millet, Geoff M. Nowell, Oliver Nebel, and Kevin W. Burton. "Simultaneous measurement of neodymium stable and radiogenic isotopes from a single aliquot using a double spike." Journal of Analytical Atomic Spectrometry 35, no. 2 (2020): 388–402. http://dx.doi.org/10.1039/c9ja00308h.
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Plomp, E., I. C. C. von Holstein, J. M. Koornneef, R. J. Smeets, L. Font, J. A. Baart, T. Forouzanfar, and G. R. Davies. "TIMS analysis of neodymium isotopes in human tooth enamel using 1013Ω amplifiers." Journal of Analytical Atomic Spectrometry 32, no. 12 (2017): 2391–400. http://dx.doi.org/10.1039/c7ja00312a.
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Michaelovitch de Mahiques, Michel, Roberto Violante, Paula Franco-Fraguas, Leticia Burone, Cesar Barbedo Rocha, Leonardo Ortega, Rosangela Felicio dos Santos, Bianca Sung Mi Kim, Rubens Cesar Lopes Figueira, and Marcia Caruso Bícego. "Control of oceanic circulation on sediment distribution in the southwestern Atlantic margin (23 to 55° S)." Ocean Science 17, no. 5 (September 15, 2021): 1213–29. http://dx.doi.org/10.5194/os-17-1213-2021.
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Abstract. In this study, we interpret the role played by ocean circulation in sediment distribution on the southwestern Atlantic margin using radiogenic Nd and Pb isotopes. The latitudinal trends for Pb and Nd isotopes reflect the different current systems acting on the margin. The utilization of the sediment fingerprinting method allowed us to associate the isotopic signatures with the main oceanographic features in the area. We recognized differences between Nd and Pb sources to the Argentinean shelf (carried by the flow of Subantarctic Shelf Water) and slopes (transported by deeper flows). Sediments from Antarctica extend up to the Uruguayan margin, carried by the Upper and Lower Circumpolar Deep Water. Our data confirm that, for shelf and intermediate areas (the upper 1200 m), the transfer of sediments from the Argentinean margin to the north of 35∘ S is limited by the Subtropical Shelf Front and the basin-wide recirculated Antarctic Intermediate Water. On the southern Brazilian inner and middle shelf, it is possible to recognize the northward influence of the Río de la Plata sediments carried by the Plata Plume Water. Another flow responsible for sediment transport and deposition on the outer shelf and slope is the southward flow of the Brazil Current. Finally, we propose that the Brazil–Malvinas Confluence and the Santos Bifurcation act as boundaries of geochemical provinces in the area. A conceptual model of sediment sources and transport is provided for the southwestern Atlantic margin.
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Aleinikoff, John N., G. Lang Farmer, Robert O. Rye, and Warren J. Nokleberg. "Isotopic evidence for the sources of Cretaceous and Tertiary granitic rocks, east-central Alaska: implications for the tectonic evolution of the Yukon-Tanana Terrane." Canadian Journal of Earth Sciences 37, no. 6 (June 1, 2000): 945–56. http://dx.doi.org/10.1139/e00-006.
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Magnetotelluric traverses across the southern Yukon-Tanana terrane (YTT) reveal the presence of a thick conductive layer (or layers) beneath Paleozoic crystalline rocks. These rocks have been interpreted to be flysch of probable Mesozoic age, on the basis of the occurrence of Jurassic-Cretaceous flysch in the Kahiltna assemblage and Gravina-Nutzotin belt flanking the YTT to the southwest and southeast, respectively. The Pb, Nd, Sr, and O isotopes in Cretaceous and Tertiary granitic rocks that crop out throughout the YTT were measured to determine if these rocks do in fact contain a component of flysch. Previous limited analyses indicated that the Pb isotopes of the granitic rocks could be a mixture of radiogenic Pb derived from Paleozoic crystalline rocks of the YTT with an increasing component of relatively nonradiogenic Pb with decreasing age. Our Nd, Sr, and O data, along with additional Pb isotope data, eliminate flysch as a likely source and strongly suggest that the nonradiogenic end-member was derived from mafic rocks, either directly from mantle magma or by melting of mafic crust. The lack of a sedimentary component in the granitic plutons suggests either that the plutons did not incorporate significant amounts of flysch during intrusion or that the conductive layer beneath the YTT crystalline rocks is not flysch.
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Hummadi, Sallama S. "Study of Nuclear Structures for Nd 148,150,152 a Isotopes by Using IBM-1." Al-Mustansiriyah Journal of Science 28, no. 2 (April 11, 2018): 196. http://dx.doi.org/10.23851/mjs.v28i2.518.
Full textAbstract:
The nuclear structures of even-even isotopes Nd (A=148,150,152) are studied by using the first
Interacting Boson Model (IBM-1). The energy levels of ground state, beta and gamma bands
,energy ratios are calculated. The results showed dynamical symmetry of these isotopes SU(3)-
SU(6), SU(5)-SU(6).
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Zaikin, D. A., M. V. Mordovskoy, and I. V. Surkova. "Interaction of low-energy neutrons with Nd isotopes." Bulletin of the Russian Academy of Sciences: Physics 74, no. 11 (November 2010): 1581–84. http://dx.doi.org/10.3103/s1062873810110183.
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Minkov, N. "Pear-shape Effects in \(^{130-136}\)Nd Isotopes." Acta Physica Polonica B Proceedings Supplement 13, no. 3 (2020): 443. http://dx.doi.org/10.5506/aphyspolbsupp.13.443.
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Gleason, J. D., P. J. Patchett, W. R. Dickinson, and J. Ruiz. "Nd isotopes link Ouachita turbidites to Appalachian sources." Geology 22, no. 4 (April 1, 1994): 347–50. http://dx.doi.org/10.1130/0091-7613(1994)022<0347:nilott>2.3.co;2.
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Garçon, Marion, Catherine Chauvel, Christian France-Lanord, Pascale Huyghe, and Jérôme Lavé. "Continental sedimentary processes decouple Nd and Hf isotopes." Geochimica et Cosmochimica Acta 121 (November 2013): 177–95. http://dx.doi.org/10.1016/j.gca.2013.07.027.
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SHELLNUTT, J. GREGORY, TUNG-YI LEE, CHIH-CHENG YANG, SHIN-TAI HU, JONG-CHANG WU, KUO-LUNG WANG, and CHING-HUA LO. "Late Permian mafic rocks identified within the Doba basin of southern Chad and their relationship to the boundary of the Saharan Metacraton." Geological Magazine 152, no. 6 (May 6, 2015): 1073–84. http://dx.doi.org/10.1017/s0016756815000217.
Full textAbstract:
AbstractThe Doba gabbro was collected from an exploration well through the Cretaceous Doba basin of southern Chad. The gabbro is composed mostly of plagioclase, clinopyroxene and Fe–Ti oxide minerals and displays cumulus mineral textures. Whole-rock40Ar–39Ar step-heating geochronology yielded a Late Permian plateau age of 257 ± 1 Ma. The major and trace elemental geochemistry shows that the gabbro is tholeiitic in composition and has trace element ratios (i.e. La/YbN> 7; Sm/YbPM> 3.4; Nb/Y > 1; Zr/Y > 5) indicative of a basaltic melt derived from a garnet-bearing mantle source. The moderately enriched Sr–Nd isotopes (i.e. ISr= 0.70495 to 0.70839; ɛNd(T)= −1.0 to −1.3) fall within the mantle array (i.e. OIB-like) and are similar to other Late Permian plutonic rocks of North-Central Africa (i.e. ISr= 0.7040 to 0.7070). The enriched isotopic composition of the Doba gabbro contrasts with the more depleted compositions of the spatially associated Neoproterozoic post-Pan-African within-plate granites. The contrasting Nd isotope composition between the older within-plate granites and the younger Doba gabbro indicates that different mantle sources produced the rocks and thus may mark the southern boundary of the Saharan Metacraton.
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Huang, Hui, Yaoling Niu, Fang-Zhen Teng, and Shui-Jiong Wang. "Discrepancy between bulk-rock and zircon Hf isotopes accompanying Nd-Hf isotope decoupling." Geochimica et Cosmochimica Acta 259 (August 2019): 17–36. http://dx.doi.org/10.1016/j.gca.2019.05.031.
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Zhang, Songsong, Xiaoyong Yang, and Lei Liu. "Evolution, Magmatic Source and Metallogenesis of A-Type Granites in the Fanchang Volcanic Basin, Middle and Lower Yangtze Metallogenic Belt: A Review." Minerals 13, no. 4 (April 18, 2023): 571. http://dx.doi.org/10.3390/min13040571.
Full textAbstract:
The Fanchang volcanic basin (FVB) is located in the Middle and Lower Yangtze Metallogenic Belt (MLYMB) between the ore districts of Ningwu and Tongling. The existing ore deposits in the FVB are relatively small in scale and related to late Mesozoic A-type granites. In this paper, the crystallization age, major and trace element composition, and Sr-Nd and Hf isotope compositions of the A-type granites are summarized from the literature; in addition, the magnetite composition, H and O isotopes of fluid inclusions, and sulfur isotope composition of metal sulfides in some typical ore deposits in the FVB are also summarized to give insights into the petrogenesis and mineralization of the A-type granites intruding into the FVB. The results show that: (1) Orthopyroxene, plagioclase, K-feldspar, and biotite are the main fractionating minerals controlling the evolution of the magmas of A-type granites in the FVB and other areas in the MLYMB. (2) The whole-rock Sr-Nd and zircon Hf isotopic characteristics show that the source of A-type granite magma is complex and includes the enriched mantle, lower crust, and upper crust, probably with stronger participation of Archaean–Paleoproterozoic crustal materials in the FVB granites than in other regions of the MLYMB. (3) The ores in the FVB are dominated by skarn and hydrothermal deposits. H and O isotopes of fluid inclusions indicate that ore-forming fluids have been derived from mixtures of magmatic hydrothermal fluid, meteoric waters, and deep brine related to gypsum layers. S isotopes of metal sulfides indicate that the sulfur may be a mixture of magmatically derived sulfur and sulfur originating from the Triassic gypsum-bearing layers. The deposit and ore characteristics of the main deposits in the FVB are also illustrated, and the evaluation of metal resources indicates that the skarn and hydrothermal iron–zinc ores in the FVB also have potential as sources of Cd, Ga, and Se. In addition, in terms of the oxygen fugacity, rock type, and geochemical characteristics of magmatic rocks, the metallogenic characteristics and potential of the A-type granites in the FVB are evaluated. It is considered that in addition to the dominant constituents of iron and zinc and the minor constituents listed above, the FVB could have the potential for providing copper, gold, molybdenum, uranium, and other metals as well.
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Niu, Xiaolu, Yildirim Dilek, Fei Liu, Guangying Feng, and Jingsui Yang. "Early Devonian ultrapotassic magmatism in the North China Craton: geochemical and isotopic evidence for subcontinental lithospheric mantle metasomatism by subducted sediment-derived fluids." Geological Magazine 158, no. 1 (August 6, 2019): 158–74. http://dx.doi.org/10.1017/s0016756819000797.
Full textAbstract:
AbstractWe report new U–Pb zircon age data, zircon in situ oxygen isotope, mineral chemistry, whole-rock geochemistry and Sr–Nd isotopic compositions from the Early Devonian ultrapotassic Gucheng pluton in the North China Craton, and discuss its petrogenesis. The Gucheng pluton is exposed in the northern part of the North China Craton and forms a composite intrusion, consisting of K-feldspar-bearing clinopyroxenite, clinopyroxene-bearing syenite and alkali-feldspar syenite. Mineral phases in these lithologies include clinopyroxene (Wo43–48En19–35Fs18–38), sanidine (An0Ab3–11Or89–97), and subordinate titanite, andradite and Na-feldspar. These rocks show homogeneous Sr but variable Nd isotopic compositions, and have relatively high zircon in situ oxygen isotopes (δ18O = 5.2–6.7). The Gucheng plutonic rocks formed through fractional crystallization and accumulation from ultrapotassic magmas, which were originated from partial melting of metasomatic vein systems in the subcontinental lithospheric mantle of the North China Craton. These vein networks developed as a result of the reactions of fluids derived from subducted pelitic sediments on the downgoing Palaeo-Asian ocean floor with the enriched, subcontinental lithospheric mantle peridotites. Sensitive high-resolution ion microprobe (SHRIMP) U–Pb zircon dating has revealed a crystallization age of 415 Ma for the timing of the emplacement of the Gucheng pluton that marks the early stages of alkaline magmatism associated with the Andean-type continental margin evolution along the northern edge of the North China Craton facing the Palaeo-Asian Ocean.
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Ayer, John A., and Jaroslav Dostal. "Nd and Pb isotopes from the Lake of the Woods greenstone belt, northwestern Ontario: implications for mantle evolution and the formation of crust in the southern Superior Province." Canadian Journal of Earth Sciences 37, no. 12 (December 1, 2000): 1677–89. http://dx.doi.org/10.1139/e00-067.
Full textAbstract:
Nd and Pb isotopes from the Lake of the Woods greenstone belt indicate the presence of three distinct reservoir sources: old enriched crust (>3.0 Ga); pre-2.7 Ga, homogeneous depleted mantle; and post-2.70 Ga heterogeneous mantle. EpsilonNd values of +1.1 to +2.3 for ultramafic to felsic metavolcanic rocks (2.742.72 Ga) indicate derivation from depleted mantle. The εNd value of 0.9 for younger turbidite (2.71 Ga), in conjunction with detrital zircon ages ranging from 2.72 to 3.0 Ga, indicates detritus from local greenstone belt sources (depleted mantle) mixed with an older crustal source. Post-2.70 Ga heterogeneity is demonstrated by εNd values ranging from 0.4 to +0.4 in shoshonitic to calc-alkaline metavolcanic rocks and +2.1 in a coeval ultrapotassic pluton. Pb isotopes from the pluton indicate derivation from a depleted mantle reservoir with an initial 207Pb/204Pb of 14.52, an initial 206Pb/204Pb of 13.29, and µ1 of 7.86. Isotopic comparison with post-2.70 Ga potassic suites from across the Superior Province indicates widespread mixing between depleted mantle and enriched end members. The enriched end member has isotopic characteristics of rocks derived from old crustal terrains, such as the Winnipeg River and Opatica subprovinces. This type of isotopic heterogeneity could be the result of crustal contamination or derivation from metasomatized mantle. Contamination of the mantle wedge by influx of fluids derived from partial melting of isotopically evolved, subducted sediments is favoured for the Superior Province potassic suite, because elevated concentration of Sr, Nd, and Pb in conjunction with primitive Mg#s suggest only limited crustal contamination has occurred.
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Li, Jianzhong, Yong Huang, Qingsong Wu, Li Zhang, Tao Xiong, Bing Wang, Zhiqiang Liang, Huawen Cao, Wei Liang, and Zuowen Dai. "Petrogenesis of the Qiongduojiang Gabbro in Tethys Himalaya and Its Metallogenetic Implication." Minerals 13, no. 6 (May 24, 2023): 721. http://dx.doi.org/10.3390/min13060721.
Full textAbstract:
With the northward subduction and final closure of the Neo-Tethyan oceanic crust, the Indian and Eurasian plates finally collided together and underwent a strong collision orogenic event, resulting in large-scale crust–mantle magmatic interactions. In order to clarify the controversies about tectono-magmatic activities after the Indian–Eurasian continental collision, we report the newly dated Eocene Qiongduojiang gabbro explored in the Tethyan–Himalaya belt, southern Tibet. LA-ICP-MS zircon U-Pb dating shows that the crystallization age of the Qiongduojiang gabbro is 46.1 ± 1.7 Ma. The whole-rock major and trace elements, as well as Rb-Sr, Sm-Nd, and Pb isotopic data results, show that the Qiongduojiang gabbro is apparently depleted in Nd isotopes, is enriched in Pb isotopes, and has maintained a consistent 87Sr/86Sr(t) value. This paper argues that the E-MORB-like Qiongduojiang gabbro originated from asthenosphere upwelling caused by slab breakoff of the Neo-Tethyan oceanic plate. This event caused large-scale magmatic activities, a magmatic mixing process between ancient crust and deep mantle, and wild distribution of Eocene Gangdese plutons along the Yarlung–Tsangpo Suture Zone, and it rendered the subduction-modified Tibetan lithosphere fertile from the Gangdese porphyry Cu deposits.