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.
Geologic Time Scale . Today, the geologic time scale is divided into major chunks of time called eons. Eons may be further divided into smaller chunks called eras, and each era is divided into periods. Figure 12.1 shows you what the geologic time scale looks like. We now live in the Phanerozoic eon, the Cenozoic era, and the Quarternary period.