The Jaramillo subchron
Another brief magnetic reversal gives the middle of the epoch a datable horizon.
- When
- —
- Duration
- 80 thousand years
- Known to
- ± 10 thousand years
- Era
- Early Pleistocene, Quaternary
From about 1.07 to 0.99 million years ago the field again flips to normal polarity. Like Olduvai, the Jaramillo is a globally correlatable time marker, and it is particularly important in the Chinese loess sequence and in European cave and river deposits where volcanic ash suitable for radiometric dating is absent. Much of the chronology of early European hominin sites hangs on where they sit relative to it.