Abstract
PROFESSOR RANKAMA1 has rightly drawn attention to the prevailing disorder in geochronological time-units and the abbreviations used for them, and his advocacy of “megayear” and “gigayear” is worthy of support. But the current international abbreviation for “year”, as adopted by the SUN Commission of the IUPAP and the British Standards Institution, is not “yr” but “a” (refs. 2 and 3) and the appropriate abbreviations for megayear and gigayear are thus Ma and Ga. The admittedly incongruous appearance (for English-speaking readers) of the first may perhaps explain why it has not yet been generally adopted.
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References
Rankama, K., Nature, 214, 634 (1967).
International Union of Pure and Applied Physics (SUN Commission), Nuclear Physics, 81, 701 (1966).
Amendment No.3 to B. S. 1991: part 1: 1954, p. 3 (1960).
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WILCOCK, B. Megayear and Gigayear. Nature 215, 102 (1967). https://doi.org/10.1038/215102b0
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DOI: https://doi.org/10.1038/215102b0
