GEOL 303 Lecture 3: Geology 303 Lecture 3
Document Summary
Has to have an origin that is not associated with a living thing. Snowflake is a mineral (so is ice), coal is not a mineral. Rocks are composed of minerals, minerals are composed of elements. 98% of the earth"s crust is composed of only 8 elements: 75% of crust is composed of only two elements: silicon and oxygen. Most minerals are silicate minerals containing both silicon and oxygen. Non-ferromagnisium silicates - light in color and weight, fe + mg poor. Ferromoagneisum silicates - dark and heavy, fe + mg rich. Sedimentary rocks - derived from the breakdown of other rock types. Metamorphic rocks - alternation of other rocks by high temperatures and pressures. Igneous rocks - cooling and crystallization of magma (important) Basalt - dark, ferromagnesium-rich; compositions of dense oceanic crust. Granite - light, ferromagnesium-poor; average composition of low-density continental crust. Relative dating - determine the age of a rock relative to other rocks.
