In their page, Rocks or Idaho; Harvey, Jacqueline, Vita Taube, and Diana Boyackarth states that the earth contains three types of rocks: igneous, metamorphic, and sedimentary rocks. Sedimentary rock makes up most of the rocks on the earth.The earth contains seventy five percent sedimentary rock. Seventy percent are sedimentary rocks that are on the earths surface, the other 5% is on the earths crust. Sedimentary rocks are formed in two main stages. First ocean waves, rivers, glaciers, wind or landslides transport loose, solid particles from weathering and erosion of preexisting rock. The particles are named sediment (Rocks of Idaho).
Next the loose sediment is converted into sedimentary rock in compaction, cementation, and recrystallization. Compaction is when the air and water is pushed out of the bottom layer of sediment as more layers build up and press down on it. Cementation is when the sediment is cemented together with natural cements like calcite and silica. This process of the loose sediment being converted into sedimentary rock is called lithification (Rocks of Idaho). Recrystallization is when unstable minerals recrystallize to form more stable minerals (South Carolina Geological Survey).
The rocks are formed in places where there had been water at one time. Dead animals, plants and pieces or rock minerals carried by wind, water, ice, and gravity sink to the bottom of bodies or water. When the body of water dries up the rock becomes a surface layer.
There's three basic types of sedimentary rock classic, chemical, and organic. Classic sedimentary rocks are formed from mechanical weathering debri. Examples are breccia, conglomerate, sandstone, and shale. Chemical sedimentary rocks form when dissolved materials precipitate from solutions. Examples are rock salt and some limestones. Organic sedimentary rock forms from the accumulation of plant or animal debris. Examples are coal and some limestones (Geoscience News and Information).
Some of the most common sedimentary rocks include sandstone, limestone, shale, and conglomerate. Sandstone is red or gray. It’s formed when sand grains are cemented together. Limestone is anywhere from white to gray, it’s made of calcite and sometimes fossils. Shale is a dark gray, and is made of compacted mud. Conglomerate is different...