Prehistory refers to the period before written history. This is a gargantuan range of time spanning nearly 4.54 billion years, from the formation of the Earth to the first written records.
There is no concrete definition to prehistory, and it is sometimes used to define the time when humans first appeared instead of the time when the Earth or life originated.
- ↑ Manhesa, Gérard; Allègre, Claude J.; Dupréa, Bernard; and Hamelin, Bruno (1980). "Lead isotope study of basic-ultrabasic layered complexes: Speculations about the age of the earth and primitive mantle characteristics". Earth and Planetary Science Letters 47 (3): 370–382. Bibcode 1980E&PSL..47..370M. doi:10.1016/0012-821X(80)90024-2.
- ↑ Fagan, Brian. 2007. World Prehistory: A brief introduction New York:Prentice-Hall, Seventh Edition, Chapter One