J.D. Walker^a and J.W. Geissman^b, *

a Department of Geology, 1475 Jayhawk Boulevard, University of Kansas, Lawrence, Kansas 66045, USA b Department of Earth and Planetary Sciences, MSC 03 2040, Northrop Hall, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, USA

Last year marked the 25th anniversary of the first Geological Society of America Geologic Time Scale (Palmer, 1983). The effort to prepare the first Society time scale was concurrent with the preparation of the 27 volumes of The Geology of North America to celebrate the Decade of North American Geology (DNAG). In 1982, an ad hoc time scale advisory committee was formed by the DNAG steering committee to encourage “uniformity among DNAG authors in the citation of numerical ages for chronostratigraphic units of the geologic time scale” (Palmer, 1983). The Time Scale Advisory Committee consisted of Z.E. Peterman (chairman), J.E. Harrison, R.L. Armstrong, and W.A. Berggren. Allison (Pete) Palmer, as centennial science program coordinator for GSA, was given the charge of compiling the committee’s efforts.

The goal of the then-unique layout of the GSA-DNAG Geologic Time Scale …

[ view current time scale ]

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DOI: 10.1130/1052-5173-19.4-5.60

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