Geologic Maps Geologic maps show the absolute ages of rock formations that outcrop on the surface. Each of the various rock layers are representing one of four major time units. These time units are defined as eras. Cenozoic is the most recent rock, Mesozoic is older than Cenozoic, even older than Mesozoic is Paleozoic, The oldest rock on earth are Precambrian.
Geologic maps use vivid colors to held distinguish the layers of rock easily.
Introduction to Earth Science Lab. Each layer of rock is older than the layer above. The acceptance that all rock sequences were originally deposited horizontally. Earth Science and the Environment. Harcourt Brace College Publishers.