Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 24 January 1997:
Vol. 275. no. 5299, pp. 498 - 499
DOI: 10.1126/science.275.5299.498
Prev | Table of Contents | Next

Perspectives

A. W. Hofmann

How did the continents form, and how long ago? These questions have been the subject of debate for 30 years. As Hofmann discusses in his Perspective, results reported by Sylvester et al. (p. 521) reveal that measurements of niobium and uranium isotopes indicate that ancient rocks from Western Australia are indistinguishable from modern mantle rock. This finding suggests that the mass and extent of continents today is comparable to that 2.7 billion years ago.

The author is at the Max-Planck-Institut für Chemie, Postfach 3060, 55020 Mainz, Germany, and is a visiting investigator at the Institut de Physique du Globe, 4 Place Jussieu, 75252 Paris, France. E-mail: hofmann{at}geobar.mpch-mainz.mpg.de

Read the Full Text

To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)