Journal articles: 'Hf isotopes'

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RATH, ASWINI KUMAR, P. M. WALKER, C. R. PRAHARAJ, and F. R. XU. "K = 6+ ISOMERS IN Hf, Yb AND W NUCLEI." International Journal of Modern Physics E 15, no. 07 (October 2006): 1653–63. http://dx.doi.org/10.1142/s0218301306005186.

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Using deformed Hartree-Fock and angular momentum projection (PHF) technique we try to understand the intrinsic structure and the systematics in the life times of K = 6+ isomers in the Hf isotopes (in 172-178 Hf nuclei) and N = 104 Yb , Hf and W isotones. The band structure in 172 Hf is reasonably well reproduced. The variation in the B ( E 2;2+ → 0+) values in the Hf isotopes as well as N = 104 isotones are well reproduced. The calculated K -forbidden E2 transition probabilities from the isomer bandheads to the 4+ yrast states qualitatively explain the variation of the lifetimes with N and Z .

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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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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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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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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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Du, Bin, Zian Yang, Lifei Yang, Qi Chen, Jiaxuan Zhu, Kangxing Shi, Gao Li, Lei Wang, and Jia Lu. "Zircon Hf-Isotopic Mapping Applied to the Metal Exploration of the Sanjiang Tethyan Orogenic Belt, Southwestern China." Applied Sciences 12, no. 8 (April 18, 2022): 4081. http://dx.doi.org/10.3390/app12084081.

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Zircon Hf-isotopic mapping can be regarded as a useful tool for evaluating the coupling relationship between lithospheric structure and metallic mineralization. Hence, this method shows important significance for mineral prediction. To explore this potential, the published granite zircon Hf isotope data from the Sanjiang Tethyan Orogen were systematically compiled. This study uses the Kriging weighted interpolation in the Mapgis software system to contour Hf isotopes, revealing a relation between the crustal structure and metallogenesis. The mapping results suggest that the Changning–Menglian suture zone is the boundary between ancient and juvenile crust, viz., the western terranes have ancient crust attributes, whereas the eastern terranes exhibit the properties of new juvenile crust. In addition, this study also found that the mineralization and element types in the Sanjiang Tethyan Orogen have a coupling relationship with the crustal structure. The distribution of porphyry Cu-Mo-Au deposits is mainly controlled by the new juvenile crust, whereas the magmatic-hydrothermal Sn-W and porphyry Mo-W(-Cu) deposits are closely related to the reworked ancient crust. The results of zircon Hf isotope mapping prove that the formation and spatial distribution of deposits are related to the composition and properties of the crust. Hf isotope mapping can reveal the regional metallogenic rules and explore metallogenic prediction and metallogenic potential evaluation.

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Caracciolo, Vincenzo, Pierluigi Belli, Rita Bernabei, Fabio Cappella, Riccardo Cerulli, Antonella Incicchitti, Matthias Laubenstein, et al. "Investigation on Rare Nuclear Processes in Hf Nuclides." Radiation 2, no. 2 (May 31, 2022): 234–47. http://dx.doi.org/10.3390/radiation2020017.

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In this work, a review of recent studies concerning rare nuclear processes in Hf isotopes is presented. In particular, the investigations using HP-Ge spectrometry and Hf-based crystal scintillators are focused; the potentiality and the results of the “source = detector” approach are underlined. In addition, a short introduction concerning the impact of such kind of research in the context of astroparticle and nuclear physics is pointed out. In particular, the study of α decay and double beta decay of 174Hf, 176Hf, 177Hf, 178Hf, 179Hf, 180Hf isotopes either to the ground state or to the lower bounded levels have been discussed. The observation of α decay of 174Hf isotope to the ground state with a T1/2=7.0(1.2)×1016 y is reported and discussed. No decay was detected for α decay of 174Hf isotope at the first excited level of daughter and of 176Hf, 177Hf, 178Hf, 179Hf, 180Hf isotopes either to the ground state or to the lower bounded levels. The T1/2 lower limits for these decays are at the level of 1016–1020 y. Nevertheless, the T1/2 lower limits for the transitions of 176Hf→172Yb (0+→0+) and 177Hf→173Yb (7/2−→5/2−) are near to the theoretical predictions, giving hope to their observation in the near future. All the other experimental limits (∼1016–1020 y) are absolutely far from the theoretical expectations. The experiments investigating the 2ϵ and ϵβ+ processes in 174Hf are also reported; the obtained half-life limits are set at the level of 1016–1018 y. Moreover, we estimate the T1/2 of 2ν2ϵ of 174Hf decay at the level of (0.3–6) × 1021 y (at now the related measured lower limit is 7.1×1016 y).

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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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Huang, Chao, Hao Wang, Jin-Hui Yang, Lie-Wen Xie, Yue-Heng Yang, and Shi-Tou Wu. "Further Characterization of the BB Zircon via SIMS and MC-ICP-MS for Li, O, and Hf Isotopic Compositions." Minerals 9, no. 12 (December 11, 2019): 774. http://dx.doi.org/10.3390/min9120774.

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In this contribution, we report the results for the characterization of the BB zircon, a newly developed zircon reference material from Sri Lanka, via secondary ion mass spectrometry (SIMS) and multiple-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). The focus of this work was to further investigate the applicability of the BB zircon as a reference material for micro-beam analysis, including Li, O, and Hf isotopes. The SIMS analyses reveal that BB zircon is characterized by significant localized variations in Li concentration and isotopic ratio, which makes it unsuitable as a lithium isotope reference material. The SIMS-determined δ18O values are 13.81‰ ± 0.39‰ (2SD, BB16) and 13.61‰ ± 0.40‰ (2SD, BB40), which, combined with previous studies, indicates that there is no evidence of conspicuous O isotope heterogeneity within individual BB zircon megacrysts. The mean 176Hf/177Hf ratio of BB16 determined by solution MC-ICP-MS is 0.281669 ± 0.000012 (2SD, n = 29) indistinguishable from results achieved by laser ablation (LA)-MC-ICP-MS. Based on the SIMS and MC-ICP-MS data, BB zircon is proposed as a reference material for the O isotope and Hf isotope determination.

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Sakhno, V. G., and L. S. Tsurikova. "Isotopic and geochemical features of the genesis of igneous complexes and ore-magmatic systems in the Chukotka sector of the Russian Arctic coast." LITHOSPHERE (Russia) 20, no. 2 (April 25, 2020): 196–211. http://dx.doi.org/10.24930/1681-9004-2020-20-2-196-211.

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Research subject. The isotopic composition (Pb-Pb, Sm-Nd, Rb-Sr, Os/Os, Hf/Hf, 3 He/4 He, etc.) of magmatic complexes and ore-magmatic systems (OMS) of two ore clusters (Kupolsky and Ilirneysky) located in the subpolar Western Chukotka was studied. These ore clusters differ from each other both in their structural position and the age of their magmatic complexes, within which the largest deposits of Au-Ag type are known. Materials and methods. The Pb-Pb, Rb-Sr, SmNd, Re-Os, Lu-Hf, 3 He/4 He, 40Ar/36Ar and sulphur isotopic systems were studied at the VSEGEI centre for isotopic studies (St. Petersburg), as well as at the Institute of Geology, Geochemistry and Ore Deposits (IGEM, Moscow) and the Laboratory of Stable Isotopes of the Far Eastern Geological Institute (FEGI, Vladivostok). Re and Os were measured using an ELEMENT-2 inductively coupled plasma single-collector mass spectrometer. Sulphur isotopic ratios were measured using a Finnigan MAT 253 isotope mass spectrometer. Results and conclusions. On the basis of the isotope-geochemical data obtained, an assumption was made that various deep sources participated in the magma generation, and the differentiated composition of late melts may reflect the melting processes of the crust upper horizons. When comparing the data on the magmatism of the Ilirneysky and Kupolsky ore clusters, a different degree of crustal rock influence on melt generation was revealed. The Kupolsky ore cluster is characterised by a large influence of mantle sources in intraplate magmatism associated with ore formation processes. This is likely to have determined a greater amount of mineralisation in the Kupolsky cluster compared to the Ilirneysky ore cluster.

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

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Abstract Hafnium (Hf) isotopes in zircon are important tracers of granite petrogenesis and continental crust evolution. However, zircon in granites generally shows large Hf isotope variations, and the reasons for this are debated. We applied U-Pb geochronology, trace-element, and Hf isotope analyses of zircon from the Miocene Himalayan granites to address this issue. Autocrystic zircon had εHf values (at 20 Ma) of–12.0 to–4.3 (median =–9). Inherited zircon yielded εHf values (at 20 Ma) of–34.8 to +0.3 (median =–13); the majority of εHf values were lower than those of autocrystic zircon. The εHf values of inherited zircon with high U concentrations resembled those of autocrystic zircon. Geochemical data indicates that the granites were generated during relatively low-temperature (<800 °C) partial melting of metasedimentary rocks, which, coupled with kinetic hindrance, may have led to the preferential dissolution of high-U zircon that could dissolve more efficiently into anatectic melt due to higher amounts of radiation damage. Consequently, Hf values of autocrystic zircon can be biased toward the values of U-rich zircon in the source. By contrast, literature data indicate that granites generated at high temperatures (>820–850 °C) generally contain autocrystic and inherited zircons with comparable Hf isotope values. During higher-temperature melting, indiscriminate dissolution of source zircon until saturation is reached will result in near-complete inheritance of Hf isotope ratios from the source. Our results impose an extra layer of complexity to interpretation of the zircon Hf isotope archive that is not currently considered.

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Kohanpour, Fariba, Christopher L. Kirkland, Weronika Gorczyk, Sandra Occhipinti, Mark D. Lindsay, David Mole, and Margaux Le Vaillant. "Hf isotopic fingerprinting of geodynamic settings: Integrating isotopes and numerical models." Gondwana Research 73 (September 2019): 190–99. http://dx.doi.org/10.1016/j.gr.2019.03.017.

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Shao-Ying, Yu, Li Yan-Xia, and Shen Cai-Wan. "Total Routhian Surface Calculations on Hf Isotopes." Communications in Theoretical Physics 50, no. 2 (August 2008): 459–62. http://dx.doi.org/10.1088/0253-6102/50/2/35.

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Simonetti, T. "Hf Isotopes in Mn-Nodules and the Oceanic Hf-Nd Isotopic Correlation as a Tracer of Lithogenic Input." Mineralogical Magazine 62A, no. 3 (1998): 1411–12. http://dx.doi.org/10.1180/minmag.1998.62a.3.73.

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Kinny, P. D., G. J. Love, and N. J. Pearson. "Hf isotopes and zircon recrystallization: A case study." Geochimica et Cosmochimica Acta 70, no. 18 (August 2006): A319. http://dx.doi.org/10.1016/j.gca.2006.06.645.

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Stracke, A., J. E. Snow, E. Hellebrand, A. von der Handt, B. Bourdon, K. Birbaum, and D. Günther. "Abyssal peridotite Hf isotopes identify extreme mantle depletion." Earth and Planetary Science Letters 308, no. 3-4 (August 2011): 359–68. http://dx.doi.org/10.1016/j.epsl.2011.06.012.

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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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Vasileiou, Polytimos, Theo J. Mertzimekis, Eirene Mavrommatis, and Aikaterini Zyriliou. "Nuclear Structure Investigations of Even–Even Hf Isotopes." Symmetry 15, no. 1 (January 9, 2023): 196. http://dx.doi.org/10.3390/sym15010196.

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The mass region of rare-earth nuclei in the nuclear chart is riddled with well-deformed nuclei, exhibiting rotational properties and many interesting nuclear structure-related phenomena. The scarcity of experimental data as the neutron number increases and the exotic phenomena such as shape coexistence, which are strongly connected with the underlying symmetries of the Hamiltonian and are predicted to take place in this region, make this mass region a fertile ground for experimental and theoretical studies of nuclear structure. In this work, we investigate the structure of the even–even 162–184Hf (hafnium) isotopes through a calculation of various observables such as B(E2;01+→21+) reduced transition matrix elements and quadrupole moments. Six different nuclear models are employed in the calculations of the observables for these nuclei, the shapes of which deviate from spherical symmetry, and as such, are characterized by Hamiltonians, which break the rotational invariance of the exact nuclear many-body Hamiltonian. The results of the present study are expected to establish some concrete guidelines for current and future experimental endeavors. Along these lines, the results for the 162–180Hf isotopes are compared with existing experimental data where available, showing an overall good agreement.

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Petersson, Andreas, Karolina Bjärnborg, Anders Scherstén, Axel Gerdes, and Tomas Næraa. "Tracing Proterozoic arc mantle Hf isotope depletion of southern Fennoscandia through coupled zircon U–Pb and Lu–Hf isotopes." Lithos 284-285 (July 2017): 122–31. http://dx.doi.org/10.1016/j.lithos.2017.04.010.

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Majeed, Wasan Z. "Investigation of density and form factor of some F isotopes using Hartree-Fock and shell model calculations." Iraqi Journal of Physics (IJP) 14, no. 30 (February 3, 2019): 158–71. http://dx.doi.org/10.30723/ijp.v14i30.211.

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Structure of unstable 21,23,25,26F nuclei have been investigatedusing Hartree – Fock (HF) and shell model calculations. The groundstate proton, neutron and matter density distributions, root meansquare (rms) radii and neutron skin thickness of these isotopes arestudied. Shell model calculations are performed using SDBAinteraction. In HF method the selected effective nuclear interactions,namely the Skyrme parameterizations SLy4, Skeσ, SkBsk9 andSkxs25 are used. Also, the elastic electron scattering form factors ofthese isotopes are studied. The calculated form factors in HFcalculations show many diffraction minima in contrary to shellmodel, which predicts less diffraction minima. The long tailbehaviour in nuclear density is noticeable seen in HF more than shellmodel calculations. The deviation occurs between shell model andHF results are attributed to the sensitivity of charge form factors tothe change of the tail part of the charge density. Calculations donefor the rms radii in shell model showed excellent agreement withexperimental values, while HF results showed an overestimation inthe calculated rms radii for 21,23F and good agreement for 25,26F. Ingeneral, it is found that the shell model and HF results have the samebehaviour when the mass number (A) increase.

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Johnson, Clark M., Steven B. Shirey, and Karin M. Barovich. "New approaches to crustal evolution studies and the origin of granitic rocks: what can the Lu-Hf and Re-Os isotope systems tell us?" Earth and Environmental Science Transactions of the Royal Society of Edinburgh 87, no. 1-2 (1996): 339–52. http://dx.doi.org/10.1017/s0263593300006738.

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ABSTRACT:The Lu-Hf and Re-Os isotope systems have been applied sparsely to elucidate the origin of granites, intracrustal processes and the evolution of the continental crust. The presence or absence of garnet as a residual phase during partial melting will strongly influence Lu/Hf partitioning, making the Lu–Hf isotope system exceptionally sensitive to evaluating the role of garnet during intracrustal differentiation processes. Mid-Proterozoic (1·1–1·5Ga ) ‘anorogenic’ granites from the western U.S.A. appear to have anomalously high εHf values, relative to their εNd values, compared with Precambrian orogenic granites from several continents. The Hf-Nd isotope variations for Precambrian orogenic granites are well explained by melting processes that are ultimately tied to garnet-bearing sources in the mantle or crust. Residual, garnet-bearing lower and middle crust will evolve to anomalously high εHf values over time and may be the most likely source for later ‘anorogenic’ magmas. When crustal and mantle rocks are viewed together in terms of Hf and Nd isotope compositions, a remarkable mass balance is apparent for at least the outer silicate earth where Precambrian orogenic continental crust is the balance to the high-εHf depleted mantle, and enriched lithospheric mantle is the balance to the low-εHf depleted mantle.Although the continental crust has been envisioned to have exceptionally high Re/Os ratios and very radiogenic Os isotope compositions, new data obtained on magnetite mineral separates suggest that some parts of the Precambrian continental crust are relatively Os-rich and non-radiogenic. It remains unclear how continental crust may obtain non-radiogenic Os isotope ratios, and these results have important implications for Re-Os isotope evolution models. In contrast, Phanerozoic batholiths and volcanic arcs that are built on young mafic lower crust may have exceptionally radiogenic Os isotope ratios. These results highlight the unique ability of Os isotopes to identify young mafic crustal components in orogenic magmas that are essentially undetectable using other isotope systems such as O, Sr, Nd and Pb.

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Bikramaditya, R. K., A. Krishnakanta Singh, Sun-Lin Chung, Rajesh Sharma, and Hao-Yang Lee. "Zircon U–Pb ages and Lu–Hf isotopes of metagranitoids from the Subansiri region, Eastern Himalaya: implications for crustal evolution along the northern Indian passive margin in the early Paleozoic." Geological Society, London, Special Publications 481, no. 1 (November 22, 2018): 299–318. http://dx.doi.org/10.1144/sp481.7.

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AbstractWe studied the zircon U–Pb ages, Hf isotopes, and whole-rock and mineral chemistry of metagranitoids from the Subansiri region of the Eastern Himalaya to constrain their emplacement age, origin and geodynamic evolution. The investigated metagranitoids have high SiO2, Na2O + K2O, Rb, Zr and low Fe2O3, Nb, Ga/Al ratios with fractionated rare earth element patterns [(Ce/Yb)N = 6.46–42.15] and strong negative Eu anomalies (Eu/Eu* = 0.16–0.44). They are peraluminous (molar A/CNK = 1.04–1.27) and calc-alkaline in nature, with normative corundum (1.04–3.61) and relatively high FeOt/MgO ratios in biotite (c. 3.38), indicating their affinity with S-type granites. The time of emplacement of the Subansiri metagranitoids is constrained by zircon U–Pb ages between 516 and 486 Ma. The zircon grains have negative εHf(t) values ranging from −1.4 to −12.7 and yield crustal Hf model ages from 1.5 to 2.2 Ga, suggesting the occurrence of a major crustal growth event in the Proterozoic and re-melting of the crust during the early Paleozoic. The geochemical data in conjunction with the U–Pb ages and Hf isotope data suggest that the Subansiri metagranitoids were produced by partial melting of older metasedimentary rocks in the Indian passive margin.Supplementary material: Hf isotope results for the Mud Tank zircon standard acquired during the experimental period are available at https://doi.org/10.6084/m9.figshare.c.4299830

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Zhang, Wei, David R. Lentz, and Kathleen G. Thorne. "Petrogenesis of the Nashwaak Granite, West-Central New Brunswick, Canada: Evidence from Trace Elements, O and Hf Isotopes of Zircon, and O Isotopes of Quartz." Minerals 10, no. 7 (July 9, 2020): 614. http://dx.doi.org/10.3390/min10070614.

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The petrogenesis of the Pridoli to Early Lochkovian granites in the Miramichi Highlands of New Brunswick, Canada, is controversial. This study focuses on the Pridoli Nashwaak Granite (biotite granite and two-mica granite). In situ trace elements and O and Hf isotopes in zircon, coupled with O isotopes in quartz, are used to reveal its magmatic sources and evolution processes. In the biotite granite, inherited zircon cores have broadly homogenous δ18OZrc ranging from +6.7‰ to 7.4‰, whereas magmatic zircon rims have δ18OZrc of +6.3‰ to 7.2‰ and εHf(t) of −0.39 to −5.10. The Hf and Yb/Gd increase with decreasing Th/U. Quartz is isotopically equilibrated with magmatic zircon rims. The biotite granite is interpreted to be solely derived by partial melting of old basement rocks of Ganderia and fractionally crystallized at the fO2 of 10−21 to 10−10 bars. The two-mica granite has heterogeneous inherited zircon cores (δ18OZrc of +5.2‰ to 9.9‰) and rims (δ18OZrc of +6.2‰ to 8.7‰), and εHf(t) of −11.7 to −1.01. The two-mica granite was derived from the same basement, but with supracrustal contamination. This open-system process is also recorded by Yb/Gd and Th/U ratios in zircon and isotopic disequilibrium between magmatic zircon rims and quartz (+10.3 ± 0.2‰).

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LIU, YU, KUNGUANG YANG, ALI POLAT, and XIAO MA. "Reconstruction of the Cryogenian palaeogeography in the Yangtze Domain: constraints from detrital age patterns." Geological Magazine 156, no. 07 (August 20, 2018): 1247–64. http://dx.doi.org/10.1017/s0016756818000535.

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AbstractDetrital zircons are often used to constrain the maximum sedimentary age of strata and sedimentary provenance. This study aimed at reconstructing the Cryogenian palaeogeography of the Yangtze Domain based on U–Pb ages and Lu–Hf isotopic signatures of detrital zircons from sandstones in the southeastern part of the Yangtze Domain. U–Pb ages of the youngest detrital zircon grains from the Niuguping, Gucheng and Datangpo formations yielded average ages of 712±24 Ma, 679.2±6.2 Ma and 665.1±7.4 Ma, respectively, which are close to the depositional ages of their respective formations. An integrated study of detrital zircon Lu–Hf isotopes and U–Pb ages from three samples revealed six main peak ages in the samples from the Anhua section atc. 680 Ma,c. 780 Ma,c. 820 Ma,c. 940 Ma,c. 2000 Ma andc. 2500 Ma. The characteristics of the U–Pb ages and Hf isotopes indicate a link between the north and southeast margins of the Yangtze Domain as early asc. 680 Ma, and the provenance of the coeval sedimentary sequences in the SE Yangtze Domain was the South Qinling Block on the northern margin of the Yangtze Domain. The provenance analysis on thec. 680 Ma detritus composing upper Neoproterozoic strata in the Yangtze Domain revealed that the detritus was transported southward from South Qinling to the southeast margin of the Yangtze Domain through the Exi Strait, but was hindered by the Jiangnan Orogenic Belt.

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Theine, K., K. P. Blume, H. H�bel, M. Murzel, J. Recht, H. Kluge, and K. H. Maier. "E ?-E ? correlation studies of light-mass Hf isotopes." Zeitschrift f�r Physik A: Atomic Nuclei 334, no. 3 (September 1989): 361–62. http://dx.doi.org/10.1007/bf01284566.

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26

Da-Li, Zhang, and Ding Bin-Gang. "Systematic Study on Triaxial Superdeformed Bands of Hf Isotopes." Communications in Theoretical Physics 51, no. 1 (January 2009): 126–30. http://dx.doi.org/10.1088/0253-6102/51/1/24.

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27

Tsivouraki, Eleni, Sotirios Chasapoglou, Michalis Serris, Michael Axiotis, Georgios Gkatis, Sotirios Harissopulos, Michael Kokkoris, Anastasios Lagoyannis, Stavros Patas, and Rosa Vlastou. "Study of the 176Hf(n,2n)175Hf cross section at 18.9 MeV." HNPS Advances in Nuclear Physics 28 (October 17, 2022): 238–41. http://dx.doi.org/10.12681/hnps.3710.

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Neutron nuclear reactions can provide significant information in the field of nuclear physics and applications. Hafnium (Hf) is one of the rare-earth isotopes with a relative large neutron total cross-section in the thermal neutron energy region and neutron induced reactions in reactor materials could lead to the production of long-lived isomeric states of Hf isotopes. Thus, the knowledge of neutron cross-sections on Hf isotopes is of great importance for basic research in Nuclear Physics as well as for applications concerning the interaction of neutrons with matter. In this study measurements of experimental cross section for the 176Hf(n,2n)175Hf and 180Hf(n,n΄γ)180mHf reactions were carried out, using the activation technique. The neutron beam energy at 18.9 MeV was produced via the 3H(d,n)4He reaction at the 5.5 MeV Tandem Van de Graaf accelerator laboratory of NCSR “Demokritos”. A thin metallic foil of natural Hf was used, while for the determination of the neutron flux at the target position a reference foil of Al was placed at the back of the Hf target. The irradiation was continuous for 28 hours leading to a total neutron fluence of 1010 n/cm2 and a BF3 detector was used for monitoring the neutron flux during the irradiation. After the end of irradiation, the activity of the Hf target and the Al foil were measured off-line by two HPGe detectors. Both detector efficiencies were obtained using a calibrated 152Eu source, placed in the same distance as the target and the reference foil. The 176Hf(n,2n)175Hf reaction has been corrected from the contribution of 177Hf(n,3n)175Hf and the 174Hf(n,γ)175Hf reactions and the 180Hf(n,n΄γ)180mHf reaction from the 179Hf(n,γ)180mHf. Theoretical calculations of the 174Hf(n,2n)175Hf, 176Hf(n,2n)175Hf and 180Hf(n,n΄γ)180mHf reaction cross-sections have also been performed using the nuclear statistical code “EMPIRE 3.2.3” and they have been compared with the data.

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28

Johnson, Beverly J., Marilyn L. Fogel, Gifford H. Miller, and Noreen Tuross. "Isotopic and molecular characterization of modern and fossil proteins in ostrich eggshell." Paleontological Society Special Publications 6 (1992): 151. http://dx.doi.org/10.1017/s2475262200007115.

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Stable carbon and nitrogen isotopes in fossil ostrich eggshell (OES) proteins have the potential to provide paleodietary information on ostriches through the Late Pleistocene in arid and semiarid regions of the Old World. Carbon isotopes may be used as a monitor for floral composition (C3 vs. C4 plant abundance), for example. The stable isotope composition of the organic matter in modern OES and Middle Holocene fossil OES samples from Bir Tarfawi (an archaeological site in southern Egypt) are presented, as well as the nature of modern proteins in OES and the degree to which they are preserved in the fossil samples.The organic fraction was extracted from OES samples and subsequently desalted by (1) decalcification in 0.5 N EDTA, followed by dialysis against water in >6-8,000 molecular weight cut off (MWCO) tubing, or (2) hydrolysis in 6N HCl for 20 minutes at 153°, followed by the addition of concentrated HF to facilitate the precipitation of CaF2. There is good agreement between the stable isotope results of the two organic fractions from modern OES samples (δ13C = −23.51±±0.76 and −23.53±±0.39, and δ15N = +6.23±±0.15 and +6.42±±0.33 for the >6-8,000 MWCO and HF preparations, respectively). A 2± and 4± enrichment between ostrich diets and the organic fraction was found for carbon and nitrogen, respectively. These relationships support a vegetarian diet comprised almost exclusively of C3 plants. Result from the HF preparation show higher variability in both the δ13C and δ15N values in the fossil samples than in the modern. This increased variability may be due to isotopic fractionation accompanying protein degradation or to inadequate methodologies for isolating the bulk organic matter. These effects could be minimized by analyzing individual molecules throughout the study.The >6-8,000 MWCO fraction of the modern and fossil OES samples were electrophoresed on SDS polyacrylamide gels. The modern sample shows predominant bands corresponding to apparent molecular weights of 14 kilodaltons (kD), 28 kD, and 35 kD, and a light smear at the top of the gel. Preliminary results of the fossil sample show a pronounced band corresponding to an apparent molecular weight of 80 kD, and a light smear over the whole gel. Results of an enzyme linked immunosorbent assay (ELISA) on the modern material demonstrate a positive antibody-antigen reaction between the >6-8,000 MWCO fraction and osteocalcin, osteonectin, and albumin.Due to the “closed-system” nature of the ostrich eggshell matrix and the ease with which it can be accurately dated through the Late Pleistocene, it provides an ideal medium for studying protein diagenesis. Subsequent isotopic analyses, using the newly developed technologies of GC/IRMS, offer an alternative method for using the paleodiets of ostriches as a tool for paleoenvironmental reconstructions in Africa and Asia.

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29

David, K., M. Frank, R. K. O'Nions, N. S. Belshaw, and J. W. Arden. "The Hf isotope composition of global seawater and the evolution of Hf isotopes in the deep Pacific Ocean from Fe–Mn crusts." Chemical Geology 178, no. 1-4 (August 2001): 23–42. http://dx.doi.org/10.1016/s0009-2541(00)00427-7.

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30

Kazakov, Andrey G., Taisya Y. Ekatova, Julia S. Babenya, Sergey S. Belyshev, Vadim V. Khankin, Alexander A. Kuznetsov, Sergey E. Vinokurov, and Boris F. Myasoedov. "Recovery of 177Lu from Irradiated HfO2 Targets for Nuclear Medicine Purposes." Molecules 27, no. 10 (May 16, 2022): 3179. http://dx.doi.org/10.3390/molecules27103179.

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A new method of production of one of the most widely used isotopes in nuclear medicine, 177Lu, with high chemical purity was developed; this method includes irradiation of the HfO2 target with bremsstrahlung photons. The irradiated target was dissolved in HF and then diluted and placed onto a column filled with LN resin. Quantitative sorption of 177Lu could be observed during this process. The column later was rinsed with the mixture of 0.1 M HF and 1 M HNO3 and then 2 M HNO3 to remove impurities. Quantitative desorption of 177Lu was achieved by using 6 M HNO3. The developed method of 177Lu production ensures high purification of this isotope from macroquantities of hafnium and zirconium and radioactive impurities of carrier-free yttrium. The content of 177mLu in 177Lu in photonuclear production was determined. Due to high chemical and radionuclide purity, 177Lu obtained by the developed method can be used in nuclear medicine.

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31

Attia, Snir, John M. Cottle, and Scott R. Paterson. "Erupted zircon record of continental crust formation during mantle driven arc flare-ups." Geology 48, no. 5 (February 14, 2020): 446–51. http://dx.doi.org/10.1130/g46991.1.

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Abstract Coupled zircon U-Pb age, trace-element, and Lu-Hf isotope analyses from central Sierra Nevada (eastern California, USA) metavolcanic strata reveal the expression of three Mesozoic arc flare-ups in the volcanic record over ∼150 m.y. of magmatic activity. Zircon εHf(i) values vary up to 20 epsilon units within individual samples and coeval sample populations but show no clear links with other geochemical indices, requiring both mixing and fractionation for arc magma genesis. Zircon compositions show repeated temporal trends across flare-ups: Hf isotopes spanning evolved to juvenile values converge to more juvenile compositions, middle rare earth element (MREE) depletion and heavy REE slopes increase during flare-up main phases, and highly variable U/Yb values converge to low values as flare-ups conclude. Despite pervasive contamination, juvenile source magmas dominate magmas erupted throughout the entirety of high-magma-addition episodes. Arc flare-ups thus represent ∼30 m.y. of increased mantle magma input that represents significant continental crust formation in Cordilleran arcs.

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32

Tarasov, V. N., K. A. Gridnev, S. Schramm, V. I. Kuprikov, D. K. Gridnev, D. V. Tarasov, K. S. Godbey, X. Viñas, and Walter Greiner. "Light exotic nuclei with extreme neutron excess and 2 ≤ Z ≤ 8." International Journal of Modern Physics E 24, no. 07 (July 2015): 1550057. http://dx.doi.org/10.1142/s0218301315500573.

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Using HF + BCS method we study light nuclei with nuclear charge in the range 2 ≤ Z ≤ 8 and lying near the neutron drip line. The HF method uses effective Skyrme forces and allows for axial deformations. We find that the neutron drip line forms stability peninsulas at 18 He and 40 C . These isotopes are found to be stable against one neutron emission and possess the highest known neutron to proton ratio in stable nuclei.

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Ahmad, Saddon T., M. Kotb, Idris H. Salih, and Hewa Y. Abdullah. "Backbending Phenomena in Even–Even $${}^{\boldsymbol{162{-}172}}$$Hf Isotopes." Physics of Atomic Nuclei 84, no. 1 (January 2021): 18–28. http://dx.doi.org/10.1134/s1063778821010063.

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34

Taqi, Ali H., and Ghanim L. Alawi. "Isoscalar giant resonance in 100,116,132Sn isotopes using Skyrme HF-RPA." Nuclear Physics A 983 (March 2019): 103–17. http://dx.doi.org/10.1016/j.nuclphysa.2019.01.001.

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35

Slama, J., J. Kosler, and R. B. Pedersen. "Deciphering metamorphic evolution of rocks by means of Hf isotopes." Geochimica et Cosmochimica Acta 70, no. 18 (August 2006): A596. http://dx.doi.org/10.1016/j.gca.2006.06.1106.

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36

Alzubadi, Ali A. "Investigation of the nuclear structure of 84-108Mo isotopes using Skyrme-Hartree-Fock method." Iraqi Journal of Physics (IJP) 13, no. 26 (February 10, 2019): 1–11. http://dx.doi.org/10.30723/ijp.v13i26.278.

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Over the last few decades the mean field approach using selfconsistentHaretree-Fock (HF) calculations with Skyrme effectiveinteractions have been found very satisfactory in reproducingnuclear properties for both stable and unstable nuclei. They arebased on effective energy-density functional, often formulated interms of effective density-dependent nucleon–nucleon interactions.In the present research, the SkM, SkM*, SI, SIII, SIV, T3, SLy4,Skxs15, Skxs20 and Skxs25 Skyrme parameterizations have beenused within HF method to investigate some static and dynamicnuclear ground state proprieties of 84-108Mo isotopes. In particular,the binding energy, proton, neutron, mass and charge densities andcorresponding root mean square radius, neutron skin thickness andcharge form factor are calculated by using this method with theSkyrme parameterizations mentioned above. The calculated resultsare compared with the available experimental data. Calculationsshow that the Skyrme–Hartree–Fock (SHF) theory with aboveforce parameters provides a good description on Mo isotopes.

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37

Neugebauer, Witold, Eric Pinet, Munsok Kim, and Paul R. Carey. "Modified method of synthesis of N-substituted dithioesters of amino acids and peptides in the Pinner reaction." Canadian Journal of Chemistry 74, no. 3 (March 1, 1996): 341–43. http://dx.doi.org/10.1139/v96-038.

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An improved method for the synthesis of dithioesters of amino acids and peptides has been developed. The syntheses have been carried out from the nitriles. The addition of thiol to the nitrile derivative in the Pinner step of dithioester synthesis was activated with hydrogen fluoride. A few examples of dithioester synthesis using liquid HF are described. Some novel dithioesters, which are model compounds for resonance Raman spectroscopic studies of dithioacylpapain intermediates, are described. Key words: dithioesters, amino acids, Pinner reaction, HF, isotopes.

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38

van Schijndel, V., G. Stevens, C. Lana, T. Zack, and D. Frei. "De Kraalen and Witrivier Greenstone Belts, Kaapvaal Craton, South Africa: Characterisation of the Palaeo-Mesoarchaean evolution by rutile and zircon U-Pb geochronology combined with Hf isotopes." South African Journal of Geology 124, no. 1 (March 1, 2021): 17–36. http://dx.doi.org/10.25131/sajg.124.0011.

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Abstract The formation and evolution of Palaeoarchaean De Kraalen and Witrivier Greenstone Belts (DKGB and WGB) of the Kaapvaal Craton are poorly known. Here we report zircon and rutile in situ U-Pb ages and zircon Hf isotopic data from a variety of supracrustal rocks. The zircon cores from a metamafic amphibole-bearing gneiss from the DKGB give a protolith age of 3 441 ± 5 Ma, whereas the zircon mantle domains give a metamorphic age of 3 211 ± 16 Ma. The 176Hf/177Hft values for all zircon domains give a tight cluster around 0.280596 ± 0.00006 (2 SD). U-Pb analyses of zircon for an amphibolite intercalated with thin calc-silicate layers from the WGB give a single crystallisation age of 3 230 ± 3 Ma, but the Hf isotope ratios of these zircon grains define two different populations. The first population yields 176Hf/177Hf~3.23 Ga = 0.28064 ± 0.00004, corresponding to εHf~3.23 Ga = 2.4 ± 1.9 (2SD) and Hf model ages between ca. 3.51 to 3.30 Ga. These are Hf isotope characteristics for zircons from a relatively juvenile source extracted from a depleted mantle source ca. 0.28 to 0.07 Ga prior zircon crystallisation. The second population yields 176Hf/177Hf~3.23 Ga = 0.28093 ± 0.00004 with εHf~3.23 Ga = 8.1 ± 1.3 (2SD). These Hf data combined with the 206Pb/207Pb ages lead to isotope ratios that lie above those of Depleted Mantle. The unusually high Hf isotope signature for the cores of the zircons from the WGB amphibolite most likely represent a contribution from an early highly depleted mantle source. A rutile in situ U-Pb age of 3.085 Ga from a recrystallised quartzite indicate that the rocks from the DKGB experienced slow cooling following the 3.21 Ga metamorphic event or (partial) resetting due to elevated geothermal gradient caused by the ca. 3.1 Ga intrusions of the Vrede Granitiod Suite. The latter interpretation is preferred because ~145 Ma of slow cooling from the amphibolite facies conditions of peak metamorphism to the blocking temperature for mass diffusion of Pb in rutile is unlikely. While the Zr-in-rutile temperature of ca. 710°C at 7 kbar for DKGB most likely records the peak temperature of the ~3.23 to 3.21 Ga event. The trace element concentrations of the metamorphic rutile grains within the quartzite of the DKGB indicate that the source rock was enriched in Cr. Either due to silification during hydrothermal alteration of the (ultra)mafic country rock or during deposition in an atmosphere that allowed for chromite grains to be part of the sediment.

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CINTRON FRANQUI, NADJA OMARA, SUNG HI CHOI, and DER-CHUEN LEE. "Peridotites and basaltic rocks within an ophiolitic mélange from the SW igneous province of Puerto Rico: relation to the evolution of the Caribbean Plate." Geological Magazine 154, no. 1 (February 2, 2016): 96–118. http://dx.doi.org/10.1017/s001675681500093x.

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AbstractThe geology of Puerto Rico is divided into three regions: the north, central and SW igneous provinces. Characterized by its Jurassic ophiolitic mélange basement, lithology of the SW Igneous Province (SIP) is not related to either of the other two provinces. The ophiolitic mélange is exposed in three peridotite belts: Monte del Estado, Rio Guanajibo and Sierra Bermeja. We present geochemical data to identify the tectonic setting of the SIP peridotite formation and its relation to the evolution of the Caribbean Plate. Comparisons of spinel Cr no. (13–21), Mg no. (63.3–69.6) and TiO2suggest an abyssal peridotite origin; however, only Sierra Bermeja presents high TiO2characteristics of a mid-ocean-ridge-basalt- (MORB-) like melt reaction. Temperatures determined with two-pyroxene geothermometers indicated a cold thermal regime ofc. 800–1050°C, with characteristics of large-offset transform fault abyssal peridotites. The geochemistry and Sr–Nd–Hf–Pb isotopic compositions of basalts within the mélange were also analysed. Las Palmas amphibolites exhibited normal-MORB-like rare earth element (REE) and trace-element patterns, whereas metabasalts and Lower Cajul basalts exhibited island-arc tholeiitic-like patterns. Highly radiogenic Sr isotopes (0.70339–0.70562) of the basalts suggest seawater alteration; however, Pb–Pb and Nd–Hf isotope correlations represent the primary compositions of a Pacific/Atlantic MORB source for the amphibolites, metabasalts and Lower Cajul basalts. We propose that the SIP ophiolitic mélange was formed along a large-offset transform fault, which initiated subduction and preserved both proto-Pacific and proto-Caribbean lithospheric mantle. Younger Upper Cajul basalts exhibited enriched-MORB-like geochemical and isotopic signatures, which can be attributed to a tectonized Caribbean ocean plateau.

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40

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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41

Rasbury, E. Troy, and Jennifer M. Cole. "Directly Dating Sedimentary Rocks." Paleontological Society Papers 12 (October 2006): 77–105. http://dx.doi.org/10.1017/s1089332600001364.

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This contribution seeks to provide a summary of radiometric dating techniques that are currently applicable to Phanerozoic sedimentary deposits and therefore relevant to paleontologists. First we overview the assumptions necessary for radiometric dating and introduce isochrons and concordia diagrams as methods for calculating ages and evaluating isotope systematics. We then focus on the four most promising systems: U-Pb dating of carbonates, Re-Os dating of black shales, and U-Pb and Lu-Hf dating of phosphates. We review expected geochemical behavior of daughter and parent isotopes in the context of both marine and terrestrial depositional environments. A critical evaluation of previously published ages and potential directions for future work are provided.

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Abdulhasan, Ali Ahmed. "Nuclear Structure Investigation of Some Ni-Isotopes Using Skyrme-Hartree-Fock Method." Iraqi Journal of Physics (IJP) 17, no. 42 (August 31, 2019): 1–12. http://dx.doi.org/10.30723/ijp.v17i42.195.

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The nuclear ground-state structure of some Nickel (58-66Ni) isotopes has been investigated within the framework of the mean field approach using the self-consist Hartree-Fock calculations (HF) including the effective interactions of Skyrme. The Skyrme parameterizations SKM, SKM*, SI, SIII, SKO, SKE, SLY4, SKxs15, SKxs20 and SKxs25 have been utilized with HF method to study the nuclear ground state charge, mass, neutron and proton densities with the corresponding root mean square radii, charge form factors, binding energies and neutron skin thickness. The deduced results led to specifying one set or more of Skyrme parameterizations that used to achieve the best agreement with the available experimental data.

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43

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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Konashi, Kenji, Kunihiro Itoh, Tsugio Yokoyama, and Michio Yamawaki. "Utilization Research and Development of Hydride Materials in Fast Reactors." Advances in Science and Technology 94 (October 2014): 23–31. http://dx.doi.org/10.4028/www.scientific.net/ast.94.23.

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Metal hydrides have high hydrogen atom density, which is equivalent to that of liquid water. An application of the hafnium hydride has been investigated as a neutron absorber in the Fast Breeder Reactors (FBRs). Fast neutrons are efficiently moderated by hydrogen in Hf hydrides and are absorbed by Hf. Since three isotopes of Hf have large cross sections, increase in the life of control rod is considered by Hf hydride. Results of design study of the core with Hf hydride control rods shows that the long lived hafnium hydride control rod is feasible in the large sodium-cooled FBR. Results of irradiation test conducted in BOR-60 has demonstrated the integrity of the capsules during irradiation. Na bonded capsule has an advantage in confinement effect of hydrogen compared with He bonded one. An application of hydride technique to transmutation target of MA was also discussed. MA hydride target is able to enhance the transmutation rate in FBR.

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45

Kalamara, A., M. Serris, A. Spiliotis, D. Sigalos, N. Patronis, M. Kokkoris, M. Diakaki, M. Axiotis, A. Lagoyannis, and R. Vlastou. "Activation cross section of the (n,2n) reaction on Hf isotopes." HNPS Proceedings 23 (March 8, 2019): 47. http://dx.doi.org/10.12681/hnps.1906.

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Cross sections of the 174Hf(n,2n)173Hf and 176Hf(n,2n)175Hf reactions have been experimentally determined relative to the 27Al(n,α)24Na reference reaction at incident neutron energies of 15.3 and 17.1 MeV by means of the activation technique. The irradiations were carried out at the 5 MV tandem T11/25 Accelerator Laboratory of NCSR "Demokritos" with monoenergetic neutron beams provided via the 3H(d,n)4He reaction, using a new Ti-tritiated target of 373 GBq activity. In the determination of the 176Hf(n,2n)175Hf reaction cross section the contamination of the 174Hf(n,γ)175Hf and 177Hf(n,3n)175Hf reactions has been taken into account. Moreover, the neutron beam energy has been studied by means of Monte Carlo simulation codes and the neutron flux has been determined via the 27Al(n,α)24Na reference reaction.

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46

Iizuka, Tsuyoshi, Takao Yamaguchi, Keita Itano, Yuki Hibiya, and Kazue Suzuki. "What Hf isotopes in zircon tell us about crust–mantle evolution." Lithos 274-275 (March 2017): 304–27. http://dx.doi.org/10.1016/j.lithos.2017.01.006.

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47

Chen, L. M., S. T. Hsieh, and H. C. Chiang. "Study of Hf isotopes in the boson-plus-fermion-pair model." Il Nuovo Cimento A 104, no. 12 (December 1991): 1713–24. http://dx.doi.org/10.1007/bf02812486.

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48

Condie, Kent C., and Richard C. Aster. "Refinement of the supercontinent cycle with Hf, Nd and Sr isotopes." Geoscience Frontiers 4, no. 6 (November 2013): 667–80. http://dx.doi.org/10.1016/j.gsf.2013.06.001.

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49

PERU, S., and J. F. BERGER. "GIANT RESONANCES IN EXOTIC SPHERICAL NUCLEI WITHIN THE HF+RPA APPROACH." International Journal of Modern Physics E 13, no. 01 (February 2004): 175–79. http://dx.doi.org/10.1142/s0218301304001916.

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The energies and characteristics of giant resonances obtained from HF+RPA calculations with the Gogny force are derived in three doubly magic exotic nuclei. The results show a lowering of the monopole resonance energy compared to systematic values in stable nuclei, in particular in 78 Ni . The Isovector Giant Dipole Resonance (IVGDR) in the two tin isotopes appears splitted into two major peaks.

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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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Abstract:

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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Journal articles on the topic 'Hf isotopes'

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