Kerrostumakivissä

Kerrostumakivissä, known in English as stratified rocks or sedimentary rocks, are a major class of rocks that are formed from the accumulation or deposition of mineral or organic particles at the Earth's surface, followed by cementation. These particles, which form the sediments, originate from weathering and erosion of pre-existing rocks, or from the precipitation of minerals from solution, or from the biological activity of organisms. Sedimentary rocks cover approximately 75% of the Earth's surface, though they make up only about 5% of the Earth's crust by volume.

The formation process of kerrostumakivissä involves several key stages. First, the source material is weathered, breaking down into smaller fragments or dissolving. These sediments are then transported by agents like water, wind, or ice. Deposition occurs when the transporting agent loses energy, causing the sediments to settle. Over time, layers of sediment accumulate, exerting pressure on the lower layers. This pressure, along with the presence of pore fluids, leads to compaction and cementation, a process where dissolved minerals precipitate in the pore spaces, binding the sediment grains together to form solid rock.

Common types of kerrostumakivissä include sandstone, shale, limestone, and conglomerate. Sandstone is composed primarily of sand-sized mineral grains or rock fragments. Shale is made of very fine-grained particles, such as clay and silt. Limestone is a chemical sedimentary rock, largely composed of calcium carbonate, often formed from the shells and skeletons of marine organisms. Conglomerates consist of rounded pebbles and cobbles cemented together. Kerrostumakivissä are significant because they often contain fossils, providing invaluable information about past life and environments. They also hold important resources such as coal, oil, natural gas, and groundwater.