Hf contents and Zr/Hf ratios in granitic zircons

Crystallization Ages of Zircons on Eucrite Parent Body from Hf-W systematics

The accretion of planetary bodies like Earth, Moon, Mars, Vesta and other meteorite parent bodies (diameter > 50 kilometers) was quickly followed by melting and metal-silicate differentiation resulting in core formation. The decay of 182 Hf [half-life (T 1/2) ~ 9 million years (Ma)] to 182 W has proved to be a very useful relative chronometer to determine the core formation and silicate differe...

Extinct 244Pu in ancient zircons.

We have found evidence, in the form of fissiogenic xenon isotopes, for in situ decay of 244Pu in individual 4.1- to 4.2-billion-year-old zircons from the Jack Hills region of Western Australia. Because of its short half-life, 82 million years, 244Pu was extinct within 600 million years of Earth's formation. Detrital zircons are the only known relics to have survived from this period, and a stud...

Early (≥4.5 Ga) formation of terrestrial crust: Lu–Hf, δO, and Ti thermometry results for Hadean zircons

Large deviations in ɛHf(T) from bulk silicate Earth seen in N4 Ga detrital zircons from Jack Hills, Western Australia, have been interpreted as reflecting a major differentiation of the silicate Earth at 4.4 to 4.5 Ga. We have expanded the characterization of Hf/Hf initial ratios (Hf ) in Hadean zircons by acquiring a further 116 laser ablation Lu–Hf measurements on 87 grains with ion microprob...

Authigenic phases and biomass contents drive Zr , Hf and REE distributions in anoxic lake sedime ts

The oldest zircons in the solar system

Here we report the occurrence, chemistry, and U-Th-Pb isotopic systematics of three meteoritic zircon assemblages, two from the Vaca Muerta mesosiderite and one from the Simmern H5 chondrite. One of the Vaca Muerta zircons occurs in the mesosiderite proper, the other in a eucritic clast associated with chromite, ilmenite, and tridymite, whereas the Simmern zircon occurs in a chondrule composed ...