Accessibility Even if plenty of water is provided, there may be other limits to its use, such as the time taken for people to travel and queue to collect it. If it takes more than 30 minutes to collect water, the amount they will collect will reduce (see Figure 9.4).
. See also Geologic(al) time scale (below). Geologic(al) time scale: a system of chronologic measurement relating stratigraphy to time that is used by geologists, paleontologists and other earth scientists to describe the timing and relationships between events that have occurred during the history of the Earth.
Epochs are subdivisions of geologic periods. Era-A division of geologic time of several hundred million years in duration. An era is smaller than an eon and longer than a period. Geologic Time Scale-A categorization of geological events based on successively smaller time spans: eons, eras, periods, epochs, and ages.Hadean-The earliest eon in the history of the Earth from the first accretion of planetary material until the date of the oldest known rocks.eologic Time Scale-A categorization of geological events based on successively smaller time spans: eons, eras, periods, epochs, and ages. Hadean-The earliest eon in the history of the Earth from the first accretion of planetary material until the date of the oldest known rocks.