The Basics of Rocks & Minerals
A mineral can be defined as a solid inorganic substance of natural occurrence.
Igneous rocks are formed when magma cools. As a result, this generates molten rock, inside the Earth or on the surface.
Sedimentary rocks are formed from the results of weathering. They are created from particles of sand, shells, pebbles, and other fragments of material.
Metamorphic rocks are formed from the transformation of existing rock types, in a process called metamorphism, which means to “change in form” over time extreme heat and pressure.
The Principle of Original Horizontality explains that sediments are deposited initially in a horizontal fashion under the action of gravity. It is a relative dating technique. The principle is essential to the examination of the folded and tilted strata.
The Law of Superposition is explained as an undisturbed arrangement of rocks that has accumulated in layers. Basically, each layer is younger than the one under it and older than the one above it.
There are two main rock structures that geologists refer to as ‘primary’ and ‘secondary’ structures:
Primary Structures are structures formed before or at the same as the material is in the process of becoming rock. For example, they are created as magma crystallizes or as sediment accumulates.
Secondary Structures are structures imposed on a rock after it has already formed. It is established as a result of compression of existing rock.
Rocks and minerals play a valuable role in natural systems by providing habitat, maintaining a healthy lifestyle, developing new technologies, and are used in our overall everyday lives.