Geologic dating ppt
The Absolute Geologic Time Scale has been developed by using a process called “Isotopic Dating”, in which the decay rates of certain radioactive materials are established and measured, then used as “clocks” to calculate the ages of various rocks.The Geologic Time Scale is illustrated here to help you see the way geologists have broken down geologic time into sections, each with an interesting and fascinating name, and each containing a package of rocks deposited during a certain time period…over the world.This aspect of Werner's model was useful for explaining the origin of tilted sedimentary rocks.(dark brown) Flat lying sedimentary rocks were eventually precipitated.The secondary rocks were thought to include interlayered basalts, which Werner thought formed by combustion of buried coal layers.The Scottish geologist James Hutton (1726-1797) argued that granite and basalt by solidification within the earth (as opposed to precipitating in from oceanwater).
You might wish to start in the Cenozoic Era (65.5 million years ago to the present) and work back through time, or start with Hadean time (4.6 to 4 billion years ago)* and journey forward to the present day it's your choice.
** The Ediacaran is the only formal system in the Proterozoic with a global boundary stratotype section and point (GSSP). A geologic time scale is composed of standard stratigraphic divisions based on rock sequences and is calibrated in years (Harland and others, 1982). Geological Survey Geologic Names Committee, 2007, Divisions of geologic time-major chronostratigraphic and geochronologic units: U.
Over the years, the development of new dating methods and the refinement of previous methods have stimulated revisions to geologic time scales.
Clouds formed and storms raged, raining more and more water down on the primitive earth, cooling the surface further until it was flooded with water, forming the seas.
It is theorized that the true age of the earth is about methods to determine the age of rocks means scientists have to rely on when the rock was initially formed (as in - when its internal minerals first cooled).