Klaus Mezger

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The timescales and mechanisms for the formation and chemical differentiation of the planets can be quantified using the radioactive decay of short-lived isotopes. Of these, the (182)Hf-to-(182)W decay is ideally suited for dating core formation in planetary bodies. In an earlier study, the W isotope composition of the Earth's mantle was used to infer that(More)
The Hf–W systematics of meteoritic and planetary samples provide firm constraints on the chronology of the accretion and earliest evolution of asteroids and terrestrial planets and lead to the following succession and duration of events in the earliest solar system. Formation of Ca,Al-rich inclusions (CAIs) at 4568.3 ± 0.7 Ma was followed by the accretion(More)
It has been assumed that Nb and Ta are not fractionated during differentiation processes on terrestrial planets and that both elements are lithophile. High-precision measurements of Nb/Ta and Zr/Hf reveal that Nb is moderately siderophile at high pressures. Nb/Ta values in the bulk silicate Earth (14.0 +/- 0.3) and the Moon (17.0 +/- 0.8) are below the(More)
The use of hafnium-tungsten chronometry to date the Moon is hampered by cosmogenic tungsten-182 production mainly by neutron capture of tantalum-181 at the lunar surface. We report tungsten isotope data for lunar metals, which contain no 181Ta-derived cosmogenic 182W. The data reveal differences in indigenous 182W/184W of lunar mantle reservoirs, indicating(More)
Vehicle positioning with an accuracy of 10 cm or less will enable lane-keeping assistance in addition to other safety benefits when an enhanced lane-level digital map is in place. With constantly evolving technology and sensors, a high-precision positioning system that fits into the automotive market can be expected within the next decade. Such a system(More)
Based on lithological, structural and geophysical characteristics, the Proterozoic Grenville Orogen of southern Ontario and New York has been divided into domains that are separated from each other by ductile shear zones. In order to constrain the timing of metamorphism, U-Pb ages were determined on metamorphic and igneous sphenes from marbles,(More)
  • Michael A. Cosca, Eric J. Essene, Klaus Mezger, Ben A. van der Pluijm
  • 1995
Geochronological data on metamorphic minerals within and outside the Bancroft shear zone, a large-scale Proterozoic shear zone, provide evidence for extensional displacement over a period of 150 m.y. This is the longest time interval yet demonstrated for any fault responding to one orogenic phase. Extensional displacement rates along the Bancroft shear(More)