Cenozoic
The shortest interval of geologic time is a nanosecond, which is one billionth of a second. It is used in some specialized fields of geology and geochronology to measure very rapid geological events or processes.
These 3 things usually happen to signal a change from one geologic time interval to another...rocks changeclimate changesdisappearances or appearances of life
No all the dinosaurs were dead by the time of the mammoth.
The longest subdivision in geologic time is the eon, which is further divided into eras. Eons represent the largest interval of time in the geologic time scale, such as the Phanerozoic eon which encompasses the last 541 million years.
The longest in geological time is an Eon eg. Archeozoic Eon . Edit: there is also the supereon, which is usually composed of 2-3 eons.
the Jurassic Period
This period is called holocene.
The shortest interval of time that can be geologically referenced is usually within a few years to decades, and it is often associated with specific events like volcanic eruptions, earthquakes, or floods. These short time intervals are typically recorded in sediment layers, ice cores, tree rings, or other natural archives.
The geologic time scale.
Eon, epoch, period, era
Geologic column is an ordered arrangement of rock layers that is based on the relative age of the rocks. Geologic time is the time IN the geologic column.
The span of geologic time subdivided into periods is called an era. Eras are further subdivided into periods to help scientists classify and study the Earth's history in a systematic way. Each period represents a distinct interval of time with its own set of characteristic geological and biological events.