A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus.
What are "rocks" and "minerals" - explain the differences. Describe essential concepts of chemistry related to earth materials. What is the chemical and mineral composition of the Earth's crust? List some common silicate and nonsilicate minerals. Describe and illustrate the "rock cycle" as it relates to processes and products. Describe basic geologic principles for interpreting landscape forming processes. On Earth, more than 4,000 minerals have been identified, however, of those fewer than 2 dozen are common minerals in Earth's physical environment (Figure 1-1 shows common rock-forming minerals).
It is conceptually important that each rock has an origin in concepts of place, time, and physical and chemical conditions. These changes may be rapid (such as a volcanic explosion) or gradual, taking place over millions or billions of years, and involving movement over great distances, both at the surface or to deep within the Earth's crust below us.
Trying to explain the what, how, and when of a rock's journey is fundamental to explaining why rocks are significant to resolving questions about our Earth's history and conditions within the physical environments where we live.
The chemical composition of Earth's crust has similarities with other stony planets, with silicate-rich rocks being dominant in most locations on the surface.
In addition, basic geologic principles can be applied to resolving the order of events leading to the formation of rocks and landscape features. Cross Sections - interpretations of vertical views of geologic features below the surface.