Although the principle of uniformity is correct in that physical laws have not changed over geologic time, Earth’s behaviour has changed as temperatures have fallen, with the consequence that the extent of igneous activity and movement of Earth’s crust has changed during geologic time.

Uniformitarianism is a theory based on the work of James Hutton and made popular by Charles Lyell in the 19th century. This theory states that the forces and processes observable at earth’s surface are the same that have shaped earth’s landscape throughout natural history.

Answer: Geological processes occurring today have always occurred in the past. – is correct about uniformitarianism.

Charles Lyell

Terms in this set (47) Uniformitarianism is the application of actualism. Uniformitarianism is when the theory of actualism is used to interpret the past.

uniformitarianism

Terms in this set (8) They provide checkpoints to estimate time (when they formed) and provide a basis for estimates as to how the Earth has changed over time. Since uniformitarianism states that Earth`s processes have been happening forever, this helps us to interpret Earth’s processes.

How did the acceptance of the uniformitarianism change the way scientists viewed Earth? They learned that Earth was very old, that Earth’s landscape is always changing, and that the processes they observed had also been at work in the past.

When sand is deposited, sandy sediment forms curved beds at an angle to the bedding plane. These beds are called cross-beds. Scientists can study the shape of the cross-beds to determine the original position of the layers.

The Law of Original Horizontality was first proposed by Danish geological pioneer Nicholas Steno in the 17th century. The law states that layers of sediment were originally deposited horizontally under the action of gravity. Any rock layers that are now folded and tilted have since been altered by later outside forces.

The Principle of Original Horizontality states that layers of sediment are originally deposited horizontally under the action of gravity. It is a relative dating technique. The principle is important to the analysis of folded and tilted strata.

The principle of original horizontality states that sediment is deposited horizontally. This is sometimes easier to envision with liquids: imagine pouring water into a cup. The surface of the water is perfectly flat – horizontal. If you dump that water into a bowl, the surface remains flat.

There are three kinds of unconformities: disconformities, nonconformities, and angular unconformities. Disconformities. Disconformities (Figure 1 ) are usually erosional contacts that are parallel to the bedding planes of the upper and lower rock units.

A paraconformity is a type of unconformity in which strata are parallel; there is no apparent erosion and the unconformity surface resembles a simple bedding plane.