How are organic rocks formed?
forms from dead plants and animals that compress deep in the Earth's crust over millions of years.
There are three types of sedimentary rocks: Clastic - rocks formed from sediment accumulated by mechanical weathering (breccia, sandstone and shale) Chemical - rocks formed from dissolved materials settling out of solution (some limestones or rock salt) Organic - rocks formed from sediment formed of plant and animal debris (coal and some limestones)
Rocks are formed from the solidification of molten magma, from the erosion and consolidation of eroded rock, or from the sedimentation of organic matter. Rocks are composed of minerals. Minerals are combinations of elements and are formed in response to many factors which include temperature, pressure, and element availability.
Sedimentary rocks are created when layers of debris are compacted and cemented together. These types of rocks are also known as secondary rocks because they often result from fragments of other rocks being cemented together. The type of sedimentary rock you seem to be asking about is organic. Organic sedimentary rock is formed when the sedimentary debris is compiled through organic processes. For example rocks forming as succesive layers of substrate pile onto one another…
Sedimentary rocks have beds/strata. They are made from decomposed materials of other rocks. Plus they they have 3 forms: clastic = compacted or cemented rock particles (consolidated); precipitated = dissolved minerals deposited as H2O (water) cools or evaporates; organic = formed from organic matter (coal) or the activities of organisms (amber). Clastic sedimentary rocks are the most common, they are either sorted or unsorted. Precipitated sedimentary rocks can be crystals or massive. Organic sedimentary rocks…
Igneous rocks are one of three classifications of rocks. Igneous rocks are formed as a direct result of crystalline solids being formed by the cooling of magma. Sedimentary rocks are the result of pieces broken from chemical, clastic and organic rock. Metamorphic rocks can be any kind of rock and are formed when a rock goes through metamorphic changes, usually due to a buried rock coming in contact with unstable minerals.
Organic sedimentary rocks like some limestones and coal are formed largely from the remains of once living organisms. Chalk and fossiliferous limestones are formed from the skeletons of marine organisms. Coal is formed from vegetation that previously existed in swampy and marshy waterlogged soils which prevented their full decay after their death. As their remains piled up and were covered by more and more deposits, they gradually underwent compaction and cementation.
Most sedimentary rocks are formed through a series of processes: erosion, deposition, compaction, and cementation. There are three major groups of sedimentary rocks: clastic rocks, organic rocks, and chemical rocks. People have used sedimentary rocks throughout history for many different purposes, including building materials and tools.