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Science 26 April 1963:
Vol. 140. no. 3565, pp. 357 - 366
DOI: 10.1126/science.140.3565.357
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Articles

Geochronology

New techniques provide knowledge of the time and mode of formation and subsequent evolution of rock systems

G. R. Tilton 1 and S. R. Hart 1

1 Geophysical Laboratory and Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, D.C.

In summary, it now seems possible to obtain accurate ages for many of the common rock types. When rocks have been affected by metamorphic episodes after the time of crystallization, it is possible to recognize this from the age values and, in some cases, to date both the time of crystallization and the time of metamorphism. Work is under way that will make it possible to draw accurate geochronological maps of the continents. An impressive regularity is already evident in the map for North America. Knowledge of the temporal and areal distribution of ages should have an important bearing on theories of the origin of continents and of mountain-building processes (50).


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
New Books.
(1965)
Science 150, 1804
   PDF »
Uranium-thorium-lead age-determinations with respect to the phanerozoic time-scale.
A. G. Darnley (1964)
Geological Society, London, Special Publications 1, 73-86
   Abstract »    PDF »


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