Physical geology examines the materials and processes of the Earth.
Historical geology examines the origin and evolution of our planet through time.
• Geology is an evolving science - the theory of plate tectonics was just accepted in the 1960's. •
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Geology seeks to understand the origin of our planet and our place in the Universe - answers to these questions are also posed outside of the realm of science.
History of Early Geology
Catastrophism (James Ussher, mid 1600s) - He interpreted that the Earth was created at 4004 B.C. Subsequent workers then developed the notion of
catastrophism, which held that the the Earth’s landforms were formed over very short periods of time.
Uniformitarianism (James Hutton, late 1700s) - He proposed that the same processes that are at work today were at work in the past. Summarized by “The present is the key to the past.” Hutton recognized
that time is the critical element to the formation of common geologic structures. Uniformitarianism is a basic foundation of modern geology.
Although catastrophism was abandoned, there is certainly evidence that sudden events do occur.
From space, Earth looks small, finite and fragile.
What's the first thing that you notice about our planet when you see this image?
The Earth is composed of several integrated parts (spheres) that interact with one another: atmosphere hydrosphere solid earth (lithosphere) biosphere
The Earth System
Hydrosphere: Oceans are the most prominent features of our (blue) planet. The oceans cover ~71% of our planet.
Atmosphere: the swirling clouds of the atmosphere represent the very thin blanket of air that covers our planet. It is not only the air we breathe, but protects us from harmful radiation from the sun.
The Earth System
Biosphere: includes all life on Earth concentrated at the surface. Plants and animals don't only