subchronn.
/ˈsʌbkrɒn/, U.S. /ˈsəbˌkrɑn/ Geology.
A time interval (chron) lasting less than 200,000 years between events, esp. reversals of the polarity of the earth's magnetic field. Cf. superchron n.
ΚΠ
1979 Geology 7 581/2 Degrees of rank for chrons, if necessary, can be formed by the prefixes sub- and super-. The time represented by the Jaramillo polarity unit might be better expressed as the ‘Jaramillo subchron’ of the ‘Matuyama chron’.
1992 Cambr. Encycl. Human Evol. (1994) v. iii. 185 (table) Magnetic polarity intervals..with the interval from 0–4.2 million years expanded to show details more clearly..Polarity subchron (event). Pleistocene. Jaramillo..Pliocene. Olduvai. Reunion. Kaena. Mammoth. Cochiti.
2011 Proc. National Acad. Sci. U.S.A. 108 10432/1 Here we present archaeological and geologic evidence that push back Dmanisi's first occupations to shortly after 1.85 Ma and document repeated use of the site over the last half of the Olduvai subchron, 1.85–1.78 Ma.
This is a new entry (OED Third Edition, September 2017; most recently modified version published online March 2022).
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n.1979