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Ma vs myr
>I wish y ou guys would stop writing "myr" for million years. In
>scientific notation the prefix "m" means milli, so "myr" means
>thousanths of a year. 100 myr would be justd o ver a month. The
>correct way is to use "M" for Mega or million. And use the
>inernational "a" for annum, not the anglocentric "yr" for year.
Actually, being even more pedantic, "Ma" can only be used for specific
dates, and not durations. Thus, the Cretaceous began at 145 Ma and ended 65
Ma, but did not last 80 Ma, but 80 million years. Unfortunately, "myr" is
often used for the latter, but hopefully someone will come up with a better
Thomas R. Holtz, Jr.
Dept. of Geology
University of Maryland
Colege Park, MD 20742