Introduction to Planet Earth – Chapter One notes
The word geology is derived from the Greek words geo and logos and means the “study of
Geology: the scientific study of the planet Earth
Geologist: is a professional who studies the planet Earth
The movement of continents on the Earth’s surface was suggested in the twentieth century
by the German meteorologist Alfred Wegener, who wrote on continental drift in 1912.
Wegener recognized that today’s continents had previously been clustered together in a
large land mass, but had subsequently moved apart. He called the land mass Pangea.
Pangea: was the supercontinent that existed during the Palaeozoic and Mesozoic eras
about 200 million years ago, before the component continents were separated into their
Wegener’s idea (with great persistence and great amounts of time dedicated to collecting
lots of evidence) ultimately allowed development of the plate tectonics theory.
Canadian geophysicist J. Tuzo Wilson was responsible for bringing together several of the
key elements in what we now know as plate tectonics theory.
Geology involves vast great amounts of time, often referred to as deep time.
Volcanic eruptions and great landslides happen fairly quickly, however they have to do with
previously stored energy. Most geological process are slow but relentless, reflecting the pace
at which the Earth’s processes work.
The Earth is estimated to be at least 4.55 million years old (4,550,000,000 years). Fossils
tell us that complex forms of life have existed on Earth for about 545 million years, Reptiles
230 million years. Dinosaurs evolved from reptiles and became extinct around 65 million
years ago. Humans have been on the Earth for about 3 million years.
Very slow geological processes are impossible to duplicate. A geologist who wants to study a
certain process cannot repeat sluggish chemical reactions that take millions of years to
occur in nature.
Exploration geologists: geoscientists who work for exploration companies looking for
gold, silver, or diamonds.
As global population becomes increasingly concentrated in larger urban “super cities,” the
risk to public safety from hazards such as volcanism, earthquakes, and severe storms is