14
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Calibration of the lutetium-hafnium clock.

      Read this article at

      ScienceOpenPublisherPubMed
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Well-defined constants of radioactive decay are the cornerstone of geochronology and the use of radiogenic isotopes to constrain the time scales and mechanisms of planetary differentiation. Four new determinations of the lutetium-176 decay constant (lambda176Lu) made by calibration against the uranium-lead decay schemes yield a mean value of 1.865 +/- 0.015 x 10(-11) year(-1), in agreement with the two most recent decay-counting experiments. 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 constant. The existence of strongly unradiogenic hafnium in Early Archean and Hadean zircons implies that enriched crustal reservoirs existed on Earth by 4.3 billion years ago and persisted for 200 million years or more. Hence, current models of early terrestrial differentiation need revision.

          Related collections

          Author and article information

          Journal
          Science
          Science (New York, N.Y.)
          American Association for the Advancement of Science (AAAS)
          0036-8075
          0036-8075
          Jul 27 2001
          : 293
          : 5530
          Affiliations
          [1 ] Institut für Mineralogie, Universität Münster, Corrensstrasse 24, 48149 Münster, Germany. escherer@nwz.uni-muenster.de
          Article
          293/5530/683
          10.1126/science.1061372
          11474108
          9bf798bc-2f40-4fe8-bcd1-50804daa2903
          History

          Comments

          Comment on this article