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Isotopic and trace element data imply a temporal change in magma sources and thermal conditions beneath the northern Fossa Magna, NE Japan arc from the Oligocene to the Pleistocene. Less radiogenic 176Hf/177Hf and 143Nd/144Nd, and high Zr/Hf characterize the Oligocene - Early Miocene volcanism in the northern Fossa Magna region. The mantle wedge in the Oligocene - Early Miocene consisted of The Central American volcanic front is noted for its systematic along-arc geochemical variations. New data show that the hafnium isotopic compositions of mafic lavas also vary regularly along the front. In detail, 176Hf/177Hf ratios are generally highest in Nicaragua and fall off toward Costa Rica and Guatemala, displaying the same along-arc chevron pattern as U/Th and Ba/La. However, unlike 176Hf/177Hf value of CHUR. calc_ab: Calculate slope and intercept calc_dens: Calculate 1D density of age data calc_dens_hist: Calculate scaled 1d density calc_dkw: Dvoretzky-Kiefer-Wolfowitz inequality 176Hf/177Hf isotopes provide information about the behaviour of so-called immobile elements in subduction environments.
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176Yb/177Hf ± 2 s.e. 176Lu/177Hf ± 2 s.e. Total Hf (V) Age (Ma) 176Hf/177Hf (t)1 Solution multi-collector ICP-MS (MC-ICP-MS) measurements of Hf isotopes from chemically purified aliquots of GHR1 yield a mean 176Hf/177Hf of 0.283050 ± 17 (2s, n = 10), corresponding to a εHf0 of +9.3. Hafnium isotopic measurements from two LA-ICP-MS laboratories are in agreement with the solution MC-ICP-MS value. A two-stage column purification method for Hf from Zr and other elements in silicate samples using the extraction chromatographic resin, UTEVA has been developed. In the first column, using an anion-exchange resin, AG 1X8, Hf, Zr and Ti were collected.
Their εHf ratios, corrected to an emplacement age of 201 Ma (-7.85 to +5.86), form a positive but shallowly sloped array slightly deviating from the terrestrial array on a εHf vs.
Deciphering the zircon Hf isotope systematics of Eoarchean
However, results obtained using was used as the primary reference material for Hf isotope ratios, with a 176Hf/ 177Hf ratio of 0.282507 ± 0.00000659. Corrected 176Lu/177Hf ratios were factor to produce the final 176Hf/177Hf and 178Hf/177Hf ratios, resulting in a During the final Hf isotope analyses, the JMC 475 Hf standard (176Hf/177Hf = Isotopic compositions are measured using H-sampler and H-skimmer cones and with glass spray chamber.
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Isotopes and Isotope Ratios 2017-03-08 · Calculates the initial 176Hf/177Hf values, the initial epsilon hafnium values, the model age using the measured 176Lu/177Hf value and the model age assuming the parental magma was produced (2012) Kimura et al. Geochemical Journal. We propose an analytical protocol for the accurate in situ determination of 176Hf/177Hf isotope ratios in zircon crystals by a 193 nm ultraviolet excimer laser ablation (193ExLA) multiple-collector inductively coupled plasma mass spectrometer (MC-ICPMS). The initial 176Hf/177Hf value (Hfi) in zircon is calculated using the measured 176Lu/177Hf, 176Hf/177Hf and apparent 207Pb/206Pb age and the 176Lu decay constant of Scherer et al. (2001) of 1.865 x 10-11.
Home » ANU Research » ANU Scholarly Output » ANU Research Publications » Meteorite zircon constraints on the bulk Lu-Hf isotope composition and early differentiation of the Earth ANU Research » ANU Scholarly Output » ANU Research Publications » Meteorite zircon constraints on the bulk Lu-Hf isotope composition and early differentiation of the
1995-01-01 · If the high 176Hf/ 177Hf ratios evolve over a time scale simi lar to the age of the oceanic crust beneath Hawaii (- 100 Ma), then the protoliths probably origi nate in the lithosphere. If the high Hf isotope ratios evolve over hundreds of millions, or bil lions, of years, then the protoliths must derive from a deeper, less transient, part of the mantle. 2002-05-01 · This article is cited by 42 publications. Christian Pin and Abdelmouhcine Gannoun . Integrated Extraction Chromatographic Separation of the Lithophile Elements Involved in Long-Lived Radiogenic Isotope Systems (Rb–Sr, U–Th–Pb, Sm–Nd, La–Ce, and Lu–Hf) Useful in Geochemical and Environmental Sciences. Normalized to 176Hf/177Hf = 0.7325, 176Hf/177Hf ranges 0.2828-0.2835, based on 24 basalt samples.
Solution data from two laboratories (Amsterdam and Münster) yield an average present day 176 Hf/ 177 Hf of 0.282000 ± 0.000005 (2σ weighted mean), which we recommend as a reference and nomination value for laser-ablation Hf isotope analyses. Cl imaging shows no visible banding or zonation for CL-active elements.
Isotopes and Isotope Ratios
2017-03-08 · Calculates the initial 176Hf/177Hf values, the initial epsilon hafnium values, the model age using the measured 176Lu/177Hf value and the model age assuming the parental magma was produced
(2012) Kimura et al. Geochemical Journal. We propose an analytical protocol for the accurate in situ determination of 176Hf/177Hf isotope ratios in zircon crystals by a 193 nm ultraviolet excimer laser ablation (193ExLA) multiple-collector inductively coupled plasma mass spectrometer (MC-ICPMS).
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Fakta Om Hafnium - 2021 Planeten jorden
This extra variation is essentially of a random nature, and can perhaps be understood in terms of known Rb The 176Lu-176Hf isotope method and its applications in earth sciences are discussed. Greater fractionation of Lu/Hf than Sm/Nd in planetary magmatic processes makes 176Hf 177Hf a powerful geochemical tracer. In general, proportional variations of 176Hf 177Hf exceed those of 143Nd l44Nd by factors of 1.5-3 in terrestrial and lunar materials. Lu-Hf studies therefore have a major contribution to Hafnium 176Hf to 177Hf isotope ratio analysis can provide insight into the different geological events and processes that a mineral underwent during its formation/metamorphosis; 176Hf/177Hf ratios 2017-12-27 4. Assuming there was no Lu incorporated into the zircon at crystallisation, the 176Hf/177Hf we measured represents the 176Hf/177Hf of its parent rock at the time of crystallisation. 2017-12-19 176Hf/177Hf isotopes provide information about the behaviour of so-called immobile elements in subduction environments.