At Siccar Point on the South East coast of Scotland you can see vertical sediments cross-cut by an erosion surface called an unconformity [
audio]. On top of this surface younger sediments have been deposited. See figure below.
Hutton realized that this relationship of stratigraphic units could have only developed as a result of Earth processes operating over many millions of years. The character of the rocks on either side (above and below) of the unconformity also speak to the vast changes in the environment that can occur over any one given point on the Earth's surface. At Siccar Point, the rocks below the unconformity were originally deposited in a deep ocean but the rocks now on top of them were deposited in a hot desert on land!
Figure 1.20 Siccar Point, Scotland, where James Hutton and his colleagues found strong evidence that confirmed his ideas about unconformities and the relationship between the rock layers. Image from Wikipedia, annotations by S. Sutherland. QUESTION: Either one of two structural processes
could have caused the Silurian beds to appear vertically oriented at this location. Which two of the following processes could do this?