Igneous rocks are formed from cooled magma. If magma cools below the earth’s surface it forms intrusive igneous rocks (gabbro); if it cools above the surface it forms extrusive igneous rocks (basalt) (Armstrong n. d. ).
As soon as rocks are exposed at the earth’s surface, the eroding or weathering process begins. Physical and chemical reactions caused by contact with air, water, and organic entities cause the rocks to break down. Erosion occurs once rocks are broken down; wind, moving water, and glaciers carry pieces of the rocks away.
Moving water is the most conventional vehicle of erosion; every year tons of sediment is carried by major rivers from the mountains to the oceans (Home Training Tools 2012 para. 6).
Under normal conditions, the force created by the mass of the newer deposits compresses the older, buried sediments. As groundwater moves through these sediments, minerals like calcite and silica precipitate out of the water and coat the sediment grains. These precipitants fill in the pore spaces between grains and act as adhesive, sticking individual particles together.
Because of seasonal or annual buildup of sediments cycles layers are seen in exposed sedimentary rocks (Home Training Tools 2012 para. 7).
If sedimentary rocks or intrusive igneous rocks are not brought to the earth’s surface by uplift and erosion, they may experience even deeper burial and be exposed to high temperatures and pressures. As a result, the rocks begin to change. Rocks that have changed below the earth’s surface due to exposure to heat, pressure, and hot fluids are called metamorphic rocks.
The Term Paper on Study Guides Earth Water Rock
Prep AP/GeographyJanuary 11, 2003 Chapter 1 Study Guide: Exploring Geography Section 1: The Five Themes of Geography 1. Geography- the study of where people, places, and things are located and of the ways in which things relate to each other. 2. Absolute location- any place or thing exact position on the globe. 3. Equator- an imaginary line that circles the globe halfway between the North and ...
