Gigannum

Grappling with time – from the nanoseconds of chemical reaction relaxation times to four gigannums of planetary convulsions – is something that actually unites geologists, planetary scientists, and astronomers (including cosmologists).

On this definition the temporal scale of neural activity tends to emphasize a milliseconds-to-seconds range, while the temporal scale of geology tends to emphasize a kiloannums-to-gigannums (thousands to billions of years) range.

The Sakju and Jongju intrusives are alkali intrusive complexes consisting of alkali pyroxenite, nephelinite, and various syenites, dating back to ~1.89–1.83 Gigannum (Ga) (Kim et al. 2016b; Lee et al. 2021b).