The sequence of development of culture or the relationship between events that represent culture can be established only when events can be placed in proper time.
Chronology, the study of events in time frame, is hence the central theme of archaeologist, like the geologist who deals with the story of earth history.
They are engaged in defining the stages of hominid evolution and their artifactual record, and the assignment of a chronology to these stages.
Chronology is the science of measuring time and ordering of the things in time.
First, it is because varve accumulation occurs only to glacial areas of the world.