Notes on Basic Geology
Notes created & information organization based on the book:
The Dynamic Earth - an introduction to physical geology"
Brian Skinner & Stephen C. Porter   (further book information here)
also look at for additional resource information
Introduction - A First Look - Page 5


Any portion of the UNIVERSE that can be isolated for study. It is a defined entity! The observer can DEFINE a system to be anything the observer wants it to be.

A system is a concept useful for the purpose of observation and study. It may be part of "other systems" or there maybe "other systems" within it.

Because it is an "isolated" entity, there must be something that differentiates it from other things. This is known as a boundary.

The boundaries are what effectively defines the system.

Types of Systems

E = mc2

Energy = mass x constant (c = speed of light)

If this is true, then there are only two fundamental things that a system can have MASS and/or ENERGY. Although not easy it is possible to covert one to the other.

There are three kinds of systems ...
Isolated system:
In an isolated system, neither Mass nor Energy is ever lost or gained. It is, in fact, a truly conceptual system since it cannot actually be created.
Closed system:
In an closed system, mass is maintained, but energy can move in and out of the system.
Open system:
In an open system both mass and energy can move in and out of the system.
It's my game and I make the rules!

What kind of system is the earth?

It is a nearly "closed system". It fundamentally has a constant mass, and energy moves in and out.

In reality some atmosphere (mass) is lost all the time, and space "dust" micrometeorites are constantly adding mass.

The earth contains four more "open systems" that allow both mass and energy to move between them. They are:

atmosphere The gases that surround the earth.
hydrosphere The entire water system minus that in the atmosphere
biosphere The organic matter
geosphere The materials that make up the "solid earth".