This unit covers basic principles of tectonic activity and weathering and slope processes. Although the human impact is designated as a sub-unit we need to regard human activities as a factor influencing weathering and slope processes rather than think of them as a separate phenomenon.
The study of the earth’s rocks is one of the relatively newer sciences, pioneered by people like Charles Lyell (1797-1875) whose book Principles of Geology opens with a quotation from the 18th century Swedish botanist, Carl Linnæus: “The stony rocks are not primeval, but the daughters of Time.” In other words the rocks of our planet have not been there in a fixed position since the dawn of time, but they change their form and are broken, melted and moulded into different shapes and states. Our study of rocks takes us on a journey in which we must become time travellers. Just look at the landscape surrounding this school and see the great limestone masses of seabed from the prehistoric Tethys Ocean, and you will see that we live alongside the memory of millions of years of these silent rocks.
Lyell’s book, which began the scientific study of geology has many pages and his own drawings devoted to volcanoes and earthquakes, a subject which clearly interested him deeply. When we remember that the theory of plate tectonics came a hundred years after Lyell, his early geology makes very interesting reading because everything he writes about must be seen in a different light.
Some good general websites on geology:
What is Geology? http://geology.com/articles/what-is-geology.shtml
The USGS: the United States Geological Society has many remarkable resources including the world’s most comprehensive seismic monitoring organisation where online updates on the world’s earthquakes happen every few minutes. http://www.usgs.gov/