How are rocks classified in the rock cycle?

Answer 1

By origin and method of formation. Igneous--molten material, sedimentary--from sediments, metamorphic--from existing rock that has undergone a physical change. The Three Rock Types and the Rock Cycle The three rock types are sedimentary, igneous, and metamorphic. At one time, early in Earth's history, all rocks were igneous, having solidified from molten rock. The rock cycle is the natural process in which rocks transform from one rock type into another rock type over time, a type of natural recycling. Igneous rocks, which are formed from magma cooling underground, or lava above ground are formed from previous igneous, metamorphic, or sedimentary rocks which have become melted, usually as a result of plate collision and subduction. When these igneous rocks are exposed to weathering and erosion, they break down into smaller particles that are transported by wind and water to a place of deposition, where they can form into sedimentary rock strata, through a process of lithification, where excess water is squeezed out by overburden pressures and the particles are cemented together by various minerals precipitating out of solution. Igneous and metamorphic rocks can both be turned into sedimentary rocks in this way. Igneous and sedimentary rocks can also be changed by heat and/or pressure into metamorphic rocks, by transforming their existing mineral structures into new minerals or realigning the existing minerals. There are different degrees of metamorphism, so even an existing metamorphic rock can become a different metamorphic rock. If these metamorphic rocks are melted, then solidify, they become igneous rocks, and the cycle starts all over again. The rock cycle is largely driven by lithospheric plate movements which cause subduction and uplift, also by climatic conditions and the associated erosion and weathering components.

Answer 2

In the rock cycle, rocks are classified by their stage in the rock cycle as igneous, metamorphic, or sedimentary; this is also their rock type and method of formation.