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hafnium isotope initial

Hafnium Isotope - an overview | ScienceDirect Topics

Among long-lived isotope systems, the best correlated in continental rocks and oceanic basalts are neodymium- and hafnium-isotope ratios. They form a very coherent positive linear trend which is taken as the “mantle–crust array” (Figure 17(a)), reflecting the effects of coupled fractionation of Sm/Nd and Lu/Hf ratios through the history of the differentiation of the silicate earth (e.g ...

Isotopes of hafnium - Wikipedia

Natural hafnium (72 Hf) consists of five stable isotopes (176 Hf, 177 Hf, 178 Hf, 179 Hf, and 180 Hf) and one very long-lived radioisotope, 174 Hf, with a half-life of 2 × 10 15 years. In addition, there are 30 other known radionuclides, the most stable of which is 182 Hf with a half-life of 8.9 × 10 6 years. No other radioisotope has a half-life over 1.87 years. Most isotopes have half ...

Hafnium isotope evidence from Archean granitic rocks for ...

Jul 01, 2012 · Hafnium isotopes in zircons have become a widely used tracer of crustal evolution. Zircon is a ubiquitous accessory phase in all granitic rocks. It resists weathering extremely well and, hence, detrital zircons are abundant in river bedload and sands. ... Fig. 5 illustrates that both present-day and initial Hf isotope compositions agree between ...

Hafnium Isotope Ratio Method for Enhanced Safeguards at ...

May 14, 2019 · The Hafnium Isotope Ratio Method for Enhanced Safeguards (HIRMES) provides a means of verifying reactor operation based upon measuring the changes in isotopic ratios in purpose-built coupons. The first activity is installing a purpose-built, integrated sample collection coupon containing hafnium which undergoes isotopic changes when irradiated ...

WebElements Periodic Table » Hafnium » isotope data

Hafnium isotopes have several applications. Hf-180 is used for the production of the radioisotope Hf-181 while Hf-180 is used for the production of the radioisotope Ta-179, which has a medical application. The second isomer of Hf-178 (Hf-178m2) exhibits a very high excitation energy and it has been suggested for use in gamma ray lasers. ...

Hafnium Isotope - an overview | ScienceDirect Topics

Among long-lived isotope systems, the best correlated in continental rocks and oceanic basalts are neodymium- and hafnium-isotope ratios. They form a very coherent positive linear trend which is taken as the “mantle–crust array” (Figure 17(a)), reflecting the effects of coupled fractionation of Sm/Nd and Lu/Hf ratios through the history of the differentiation of the silicate earth (e.g ...

Hafnium | Hf (Element) - PubChem

Geologists can use calculated lutetium-hafnium ages and the initial isotope-amount ratio n(176 Hf)/n(177 Hf) along with other isotopic data from the oldest rocks in the Earth to infer that the Earth’s crust differentiated within the first few hundred million years after condensation of the oldest solid matter in the Solar System [502].

(PDF) Hafnium isotope composition of zircons from dunites ...

The initial hafnium isotope composi- and the peculiarities of their internal structure and age tion of zircon from dunites of the Guli massif also var- are given in the table and Figs. 1 and 2. ies in broad limits (176Hf/177Hfi from 0.281051 to Cathode-luminescent images of some crystals 0.0.281376; εHf from 1.1 to 10.0; table, Figs. 1q–1t ...

Hafnium-177, Hafnium-177 Isotope, Enriched Hafnium-177

Hafnium-177 Information. Hafnium is a silvery lustrous metallic transition element. It is used in tungsten alloys in filaments and electrodes. This element acts also as a neutron absorber. Hafnium was reported by Urbain firstly in 1911, its existence was finally established by D. Coster in 1923 and by G.C. de Hevesy at the same time.

PSRD: Hafnium, Tungsten, and the Differentiation of the ...

Nov 28, 2003 · The isotopes include both those with long half lives, such as rubidium-87 (87 Rb, half life of 48.8 billion years), which decays to strontium-87 (87 Sr), and those that have half lives that are so short that the radioactive isotope no longer exists. The hafnium-182 (182 Hf)-tungsten-182 (182 W) pair is

The Source Region and Melting Mineralogy of High-Titanium ...

Five high-Ti basalts from the Apollo 11 and 17 landing sites have been analyzed for their hafnium isotope composition. These data serve to better constrain the hafnium isotope variation of the Moon's mantle. Variations in initial ∊ Hf and ∊ Nd values of low- and high-Ti basalts imply that the source region mineral assemblages of these lunar magma types are distinct.

Nature of the Earth's earliest crust from hafnium isotopes ...

May 20, 1999 · Nature of the Earth's earliest crust from hafnium isotopes in single detrital zircons. May 1999; Nature 399(6733) DOI:10.1038/20426. ... broad range of

Nature of the Earth's earliest crust from hafnium isotopes ...

May 20, 1999 · Here we report hafnium-isotope data, obtained using the new technique of multiple-collector plasma-source mass spectrometry9, for 37 individual

Calibration of the Lutetium-Hafnium Clock - 百度学术

Lutetium-hafnium ages that are based on the previously used lambda176Lu of 1.93 x 10(-11) to 1.94 x 10(-11) year(-1) are thus approximately 4% too young, and the initial hafnium isotope compositions of some of Earth's oldest minerals and rocks become less radiogenic relative to bulk undifferentiated Earth when calculated using the new decay ...

Isotopes of hafnium - WikiMili, The Free Encyclopedia

Jul 16, 2019 · Isotopes of hafnium. Natural hafnium ( 72 Hf) consists of five stable isotopes ( 176 Hf, 177 Hf, 178 Hf, 179 Hf, and 180 Hf) and one very long-lived radioisotope, 174 Hf, with a half-life of 2 × 1015 years. In addition, there are 30 other known radionuclides, the most stable of which is 182Hf with a half-life of 8.9 × 106 years.

Meteorite zircon constraints on the bulk Lu−Hf isotope ...

Apr 28, 2015 · The radioactive decay of lutetium-176 to hafnium-176 has been used to study Earth’s crust−mantle differentiation that is the primary agent of the chemical and thermal evolution of the silicate Earth. Yet the data interpretation requires a well-defined hafnium isotope growth curve of the bulk Earth, which is notoriously difficult to reconstruct from the variable bulk compositions of ...

Hafnium cyber-attack neutralized by AI in December 2020 ...

Apr 16, 2021 · Darktrace AI appears to have detected a Hafnium attack against vulnerable Exchange servers in December 2020, three months before the zero-day was identified. This blog provides an in-depth analysis of the attack, which suggests that Hafnium’s campaign began far

Discovery of Gallium, Germanium, Lutetium, and Hafnium ...

The discovery of gallium, germanium, lutetium, and hafnium isotopes is discussed as part of the series summarizing the discovery of isotopes, beginning with the cerium isotopes in 2009 [1]. Guidelines for assigning credit for discovery are (1) clear identi cation, either through decay-curves and relationships to other known isotopes, particle or

Thorium - Wikipedia

Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately soft, malleable, and has a high melting point.Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when ...

Hafnium isotope evidence from Archean granitic rocks for ...

Jul 01, 2012 · Highlights Zircons and their host whole-rocks have consistent Hf isotope compositions. The U–Pb system in old zircons is often disturbed, leading to spurious initial ε Hf. Time-integrated source Lu/Hf for TTGs and zircons has been chondritic for 4 Gy. Continental crust derives from the deep rather than the depleted upper mantle. Oceanic plateau recycling was the major crustal growth process ...

Hafnium Isotope Ratio Method for Enhanced Safeguards at ...

May 14, 2019 · The Hafnium Isotope Ratio Method for Enhanced Safeguards (HIRMES) provides a means of verifying reactor operation based upon measuring the changes in isotopic ratios in purpose-built coupons. The first activity is installing a purpose-built, integrated sample collection coupon containing hafnium which undergoes isotopic changes when irradiated ...

Isotopes of hafnium - WikiMili, The Free Encyclopedia

Jul 16, 2019 · Isotopes of hafnium. Natural hafnium ( 72 Hf) consists of five stable isotopes ( 176 Hf, 177 Hf, 178 Hf, 179 Hf, and 180 Hf) and one very long-lived radioisotope, 174 Hf, with a half-life of 2 × 1015 years. In addition, there are 30 other known radionuclides, the most stable of which is 182Hf with a half-life of 8.9 × 106 years.

Hafnium isotope evidence for the origin of Cenozoic ...

Hafnium isotope evidence for the origin of Cenozoic basaltic lavas from the southwestern United States Brian L. Beard and Clark M. Johnson Department of Geology and Geophysics, University of Wisconsin-Madison Abstract. Hafnium isotope analyses of 52 Cenozoic

Hafnium - Periodic Table and Atomic Properties

Mass numbers of typical isotopes of Hafnium are 176-178, 179, 180. Atomic Mass of Hafnium. Atomic mass of Hafnium is 178.49 u. The atomic mass is the mass of an atom. The atomic mass or relative isotopic mass refers to the mass of a single particle, and therefore is tied to

Hafnium isotope evidence for the origin of Cenozoic ...

Sep 10, 1997 · Hafnium isotope Hafnium analyses of 52 Cenozoic basalts from the southwestern United States document the differences and similarities of the mantle beneath the continents, as compared to the suboceanic mantle. One of the major conclusions of this work is documentation of a widespread Nd-Hf isotope array that is oblique to that of the oceanic ...

Hafnium Isotope Composition of Zircon from the Kondyor ...

Aug 06, 2019 · Zircons of the Kondyor massif are characterized by wide variations in the initial Hf-isotope composition (176 Hf/ 177 Hf i = 0.28113–0.28292, Table 1, Fig. 3a). The most pronounced variations in εHf values are typical for the Mesozoic zircons (εHf from –8.4 to +10.5, n = 13, Fig. 3b).

Hafnium isotopic disequilibrium during sediment melting ...

Jan 15, 2020 · Kemp, A.I.S., Hawkesworth, C.J., Paterson, B.A., Kinny, P.D. (2006) Episodic growth of the Gondwana supercontinent from hafnium and oxygen isotopes in zircon. Nature 439, 580. ). Zircon retains the initial melt isotopic composition because of its low Lu/Hf ratio and refractory nature in sedimentary processes (Andersen et al., 2002

Chondritic initial Os/ Os in Slab-melting for high-Mg ...

Contribution from hafnium isotope geochemistry T. H ANYU AND Y. T ATSUMI Institute for Frontier Research on Earth Evolution, Japan Marine Science and Technology Center ([email protected], [email protected]) High-Mg andesites (HMA) and associated basalts in the Setouchi volcanic belt, SW Japan were analyzed for Hf

Zircon oxygen and hafnium isotope decoupling during ...

Dec 05, 2019 · Zircon is a common accessory mineral found in a range of rock types in many geological environments. Crystalline zircon is not only highly retentive of elements such as U, Th, Pb, Hf, and middle-to-heavy rare earth elements (M-, H-REE) but also its primary oxygen isotope composition (δ 18 O) can be preserved up to temperatures of 800–900 °C in favourable cases (Watson and Cherniak

Hafnium and iron isotopes in early Archean komatiites ...

We present radiogenic Hf and stable Fe isotopes for a series of komatiites from the Pilbara craton in Western Australia (aged 3.5 to 2.9 Ga). After careful evaluation of the effects of alteration, we find that pristine samples are characterised by a light Fe isotope mantle source and initial 176Hf/177Hf well above the age-corrected depleted mantle.

It's Elemental - The Element Hafnium

The Element Hafnium - Known Isotopes. Most of the isotope data on this site has been obtained from the National Nuclear Data Center.Please visit their site for more information.. Isotopes With A Known Natural Abundance

A reconnaissance ion-probe study of hafnium isotopes in ...

A SIMS technique for the isotopic analysis of hafnium in zircons using the SHRIMP ion microprobe has been developed, and a precision of typically 0.5%. (2σ) achieved in the mean reduced 176 Hf / 177 Hf ratio measured at several spots on a single grain. Unfractionated (chondritic) initial Hf isotopic compositions have been measured on a number of Archaean zircon populations.

Alpha-decay half-life of Hafnium isotopes reinvestigated ...

However, despite the importance of 176Hf isotope, up to now no data have been reported regarding its decay and 176Hf is currently considered a stable isotope (Holden et al., 2019). It should be mentioned that the discrepancies found in the initial Hafnium-isotope ratios, originating mainly from uncertainties, or even lack, of decay data make ...