Definition of deep time in US English:

deep time


  • The multimillion year time frame within which scientists believe the earth has existed, and which is supported by the observation of natural, mostly geological, phenomena.

    • ‘On the scale of deep time, or within the scope of a system as complex as a planetary ecosystem, it is not even theoretically possible to determine cause and effect.’
    • ‘The most unsettling aspect of geological deep time was the loneliness of pre-Adamic history, a time span of many millions of years that had gone unwitnessed by human eyes.’
    • ‘The question of how the Sun shines - that is, the source of its energy - did not become a matter of concern among scientists until the concept of geological deep time was established.’
    • ‘Archaeology possesses the technical apparatus for the investigation of deep time through excavation and chronometric dating.’
    • ‘Here they will learn to contemplate the environment in the context of deep time and to study the processes that create landscape and climate (as well as some limited chemistry), upon which life depends.’