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Neoproterozoic rifting i det övre yangtze kontinentala blocket

18 Jun 2012 176Hf/177Hf isotope ratios of zircons from the Chelopech magmatic rocks, together with published data on the Chelopech area and the about Hf-176 Isotope, Enriched Hf-176, Hf-176 Oxide, Hf-176 Price, Hf-176 Applications , Hf-176 Properties, Buy Hf-176 Isotope. The significant correlations of Rb/Sr vs 87Sr/86Sr, Sm/Nd vs 143Nd/144Nd and Lu/Hf vs 176Hf/177Hf give pseudochron ages of 182 ± 33 Ma, 276 ± 50 Ma and The oldest (3.84–3.82 Ga) zircon cores have tightly clustered 176Hf/177Hf ratios that are consistent with derivation of their tonalitic precursors from chondritic 91500 reference zircon and after evaluating the existing ICPMS and TIMS data we calculate a mean 176Hf/177Hf value of 0.282303 ± 0.000003 (2σ). NF · t1/2 · ST · SE (MeV), SP. 172Hf, {syn.} 1,87 år · ε, 0,350, 172Lu. 174Hf, 0,162 %, 2 × 1015 år, α, 2,495, 170Yb. 176Hf, 5,206 %. Stabil.

Sci. Lett., 129 (1–4) (1995), pp. 13-30. Article Download PDF View Record in Scopus Google 2011-09-01 · Highlights Zircons from granites of the New England Batholith have a range of Hf isotopes. The range of Hf isotopes indicates mixing between crustal and mantle-derived magmas. We examine the relationships between zircon Hf isotopes and rock geochemistry. We argue that the crust and mantle derived magmas are silicic in composition.

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.

Mesoproterozoisk juvenilskorpa i mikrokontinenter av det

Trace elements in zircon do not show systematic variations no straightforward link to processes. 176Hf/177Hf in the rims are diﬀerent than in the cores in (t) C-833-A suggesting contribution of a Hf-enriched melt/ﬂuid.

Mesoproterozoisk juvenilskorpa i mikrokontinenter av det

Although these They record precise U-Pb ages and initial 176Hf/177Hf isotope ratios providing important constraints on the age and nature of the metasomatic events occurring in Our 176Hf/177Hf results of both mafic and felsic geochemical reference standards agree with those reported by other authors. 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. 176Hf/177Hf ratios are corrected to 179Hf/177Hf = the Hf isotope measurements were verified by repeated analyses of reference zircon GJ-1 and Temora, which yielded a 176Hf/177Hf of 0.282008 ± 0.000019 ( 2 The 176Hf/177Hf ratios are 0.281231±24 (2SD, n=20),.

76. February 11, 2009. εHf = ( 176 Hf /177 Hf )sample −(176 Hf /177 Hf )Chon.
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Geochemistry, Geophysics, Geosystems. Using high-precision multiple collector inductively coupled plasma-mass spectrometry (MC-ICP-MS), 176Hf/177Hf was measured in 64 mid-ocean ridge basalts (MORB) from the Mid-Atlantic Ridge … 1 calculated using the 176Lu decay constant of Soderlund et al. (2004) at the assigned age, t. 176Hf/177Hf ratio is a combination of two deter- minations. Two loading methods were primarily used, one following the method of Corfu and Nobel [25], which uses a single Re filament with an Ir-C slurry, and the other following the method of Patchett and Tatsumoto [22 The similarity of the Lu–Hf and Sm–Nd isotope system during most mantle differentiation processes makes the combination of 176Hf/177Hf and 143Nd/144Nd a very sensitive indicator of a select number of processes. This paper present new Hf-isotope data for a large number of ocean islands and examines the Hf–Nd–Pb isotope relations of oceanic volcanics. 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.

εNd diagram. Hf isotopic analyses of all 6 fractions yielded very consistent results with the average 176Hf/177Hf=0.282174 ± 12 (2 S.D.), relative to JMC-475 176Hf/177Hf=0.282162 ± 5 (2 S.D.). Laser ablation analyses of individual grains from the six fractions yielded similar results, with an average 176Hf/177Hf=0.282174 ± 15 (2 S.D.). 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.

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.
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The Central Scandinavian Dolerite Group : Protracted hotspot

176Lu/177Hf is the intensity of 176Lu, calculated from the measured instensity of 175Lu and 176Lu/175Lu=0.02653 (from Patchett, 1983), compared to the measured intensity of 177Hf. Fractionation of Lu Request PDF | Coupled Trace Element and Isotope Variations in Oceanic Basalts: Recycling Re-examined | In 1982 Hofmann and White (Nature, 295, p.363). proposed that the enriched mantle components The samples define two geochemical groups: high-MgO samples with higher 87Sr/86Sr, lower 143Nd/144Nd and 176Hf/177Hf, and a positive correlation of Sr and Pb isotopes; and low-MgO samples displaying lower 87Sr/86Sr but higher 143Nd/144Nd and 176Hf/177Hf than the former group, and a negative correlation of Sr and Pb isotopes. 176Hf/177Hf allowed to constrain the crystallization age (t) of the protolith. Trace elements in zircon do not show systematic variations no straightforward link to processes. 176Hf/177Hf in the rims are diﬀerent than in the cores in (t) C-833-A suggesting contribution of a Hf-enriched melt/ﬂuid. In sample C-838-A, 176Hf/177Hf suggests (t) 2015-10-15 · Extreme 176Hf/177Hf in the sub-oceanic mantle.