Geologic age dating sequence
Uniformtarianism does not require that all geological processes are slow.
Some are abrupt, such as an explosive volcanic eruption, an earthquake, or a landslide.
Lyell was a significant scientific presence through much of the time of Victorian England in the 1800s.
He had a large influence on the development and spread of the practice of geology as a science, partly through his textbook, that Charles Darwin read had a major influence in his thinking as he traveled around the world collecting samples, and Darwin consulted with Lyell at key stages during the time he developed and published his theory of evolution of species by natural selection.
Relative geologic age is established, based on such evidence as the order in which layers of sediment are stacked, with the younger layer originally on top.
By using the principles of relative geologic age, the sequence of geologic events -- what happened first, what happened next, what happened last -- can be established.
In the two centuries after Steno developed the first set of principles for determining relative geologic age, other geologists contributed major ideas that have allowed scientists to grapple with, measure, and come to terms with geologic time.
The first incorrect interpretation is that it states that only slow changes occur on earth, the second misinterpretation is that it states that catalclysmic events cannot have happened in the past.Geologic time covers the whole sweep of earth's history, from how and when the earth first formed, to everything that has happened on, in, and to the planet since then, right up to now.Geologists analyze geologic time in two different ways: in terms of relative geologic age, and in terms of absolute (or numeric) geologic age.An unconformity is a buried erosional surface or non-depositional surface, a contact between the rocks below and the layer of stratified rock above that is missing a significantly large interval of geologic time.
For example, deep in the Grand Canyon in Arizona, there are places where a layer of rock of Devonian age is right on top of a layer of rock of Cambrian age.Steno made careful geologic observations and illustrations.