Final answer:
The ICS, or International Chronostratigraphic Chart, is a framework used in geology to divide and correlate Earth's history. It is based on an international consensus among geologists and is continuously updated. The ICS uses specific criteria and markers to define the boundaries between different time units.
Step-by-step explanation:
The ICS, or International Chronostratigraphic Chart, is a framework used in geology to divide and correlate Earth's history. It provides a system for organizing and classifying geological time periods based on significant events and changes in Earth's environment. The ICS is composed of a hierarchy of units such as eras, periods, epochs, and ages.
One characteristic of the ICS is that it is based on an international consensus among geologists and geoscientists. This ensures that the divisions and boundaries of geological time are consistent across different regions and countries. Another characteristic is that the ICS is continuously updated and revised as new scientific discoveries and research emerge. This allows for a more accurate understanding of Earth's history.
Lastly, the ICS uses specific criteria and markers, such as changes in fossil records, sedimentation patterns, and geological events, to define the boundaries between different time units. These criteria enable scientists to establish the relative and absolute ages of rocks and geological formations.