1. Weathering and Erosion: Igneous rocks, exposed at the Earth's surface, are broken down by weathering (physical and chemical processes).
* Physical weathering: This involves forces like wind, rain, ice, and temperature changes that break down the rock into smaller pieces.
* Chemical weathering: This involves chemical reactions, like the dissolving of minerals by acidic rain or the oxidation of iron, changing the rock's composition.
2. Transportation: The weathered fragments are transported away from their original location by agents like wind, water, or ice. This process often rounds and smooths the rock fragments.
3. Deposition: Eventually, the transported rock fragments, called sediment, settle and accumulate in a new location. This can occur in a variety of environments like riverbeds, lake bottoms, or ocean floors.
4. Compaction and Cementation: Over time, the sediment layers are buried under additional sediment. The weight of the overlying layers compresses the sediment, squeezing out water and air. Dissolved minerals in the water then precipitate out, acting as a glue to bind the sediment grains together. This process is called lithification, which turns the loose sediment into solid rock.
5. Sedimentary Rock Formation: The hardened and cemented sediment becomes sedimentary rock. This rock will have a unique texture and composition depending on the type of igneous rock it originated from and the conditions of its transport and deposition.
Example:
* A granite rock (igneous) is weathered into sand-sized particles.
* These particles are carried by a river and deposited on a beach.
* Over millions of years, the sand layers are buried and compacted, with minerals cementing the grains together.
* This results in the formation of sandstone (sedimentary).
Important Note: This process takes a very long time, often millions of years. The transformation of igneous rock to sedimentary rock is part of the rock cycle, a continuous process that recycles Earth's materials.
