Mountains have been built and eroded, continents and oceans have moved great distances, and the Earth has fluctuated from being extremely cold and almost completely covered with ice to being very warm and ice-free.
These changes typically occur so slowly that they are barely detectable over the span of a human life, yet even at this instant, the Earth's surface is moving and changing.
Furthermore, useful fossils are either rare or totally absent in rocks from Precambrian time, which constitutes more than 87 percent of Earth history.
Precambrian rocks must therefore be correlated by means of precise isotopic dating.
The impact of the radiocarbon dating technique on modern man has made it one of the most significant discoveries of the 20th century.
No other scientific method has managed to revolutionize man’s understanding not only of his present but also of events that already happened thousands of years ago.
As these changes have occurred, organisms have evolved, and remnants of some have been preserved as fossils.
It is rapidly oxidized in air to form carbon dioxide and enters the global carbon cycle.The basis for assuming that like fossils indicate contemporary formation is faunal succession.However, as previously noted, times of volcanism and metamorphism, which are both critical parts of global processes, cannot be correlated by fossil content.These rocks are tilted due to deposition on the non-horizontal surfaces of primitive rocks.This aspect of Werner's model was useful for explaining the origin of tilted sedimentary rocks.Hutton viewed tilted strata as having been initially deposited horizontally, and then were subsequently deformed (tilted and folded) by the forces of Earth's internal heat engine.