1. Weathering and Erosion:
* Weathering: Igneous rocks exposed at the Earth's surface are broken down by various weathering processes:
* Physical weathering: Mechanical forces like freezing/thawing, abrasion by wind and water, and plant roots break the rock into smaller pieces.
* Chemical weathering: Reactions with water, oxygen, and acids dissolve or alter the minerals within the rock.
* Erosion: Once broken down, the weathered fragments are transported away from their original location by wind, water, or ice.
2. Transportation and Deposition:
* Transportation: The eroded fragments are carried by wind, water, or ice. During this journey, they are further broken down and sorted by size and density.
* Deposition: Eventually, the carrying power of the transport agent decreases, leading to the deposition of the sediments in a new location, like a lake, riverbed, ocean floor, or desert.
3. Compaction and Cementation:
* Compaction: As layers of sediment accumulate, the weight of the overlying layers presses down on the lower layers, squeezing out water and air, and reducing the volume of the sediment.
* Cementation: Dissolved minerals in the pore spaces between sediment grains precipitate out, acting like glue to bind the sediment particles together, forming solid rock.
4. Lithification:
* The combined processes of compaction and cementation are known as lithification, the final step in the transformation of loose sediment into solid sedimentary rock.
Summary:
1. Weathering and Erosion: Break down igneous rocks.
2. Transportation and Deposition: Move and deposit the fragments.
3. Compaction and Cementation: Squeeze and glue the fragments together.
4. Lithification: The final step to form solid sedimentary rock.
Important Note: Not all igneous rocks will form sedimentary rocks. Some might be buried deep within the Earth and remain igneous. Others might be metamorphosed under intense heat and pressure, forming metamorphic rocks.
