1. Igneous Rock to Sedimentary Rock

* Weathering and Erosion: Igneous rocks exposed at the Earth's surface are broken down by weathering (physical and chemical processes) into smaller pieces called sediments.

* Transportation: These sediments are transported by wind, water, or ice to new locations.

* Deposition: The sediments settle and accumulate in layers.

* Lithification: Over time, the layers of sediment are compacted by the weight of overlying layers and cemented together by minerals dissolved in groundwater. This process is called lithification, and it forms sedimentary rock.

2. Sedimentary Rock to Metamorphic Rock

* Heat and Pressure: Sedimentary rocks buried deep within the Earth's crust are subjected to intense heat and pressure.

* Recrystallization: The minerals in the sedimentary rock are unstable under these conditions and start to recrystallize into new minerals that are more stable at higher temperatures and pressures.

* Texture Changes: The original sedimentary layers and textures are often altered or destroyed during the process.

Examples:

* Igneous Rock: Granite

* Sedimentary Rock: Sandstone (formed from weathered granite)

* Metamorphic Rock: Gneiss (formed from metamorphosed sandstone)

The Rock Cycle

This entire process of transformation is part of the rock cycle, a continuous process that describes the formation, breakdown, and reformation of rocks over geological time.

Key Points:

* No single rock type is permanent: Rocks are constantly being transformed through the rock cycle.

* The rock cycle is driven by Earth's internal heat and external forces like weathering and erosion.

* Rocks can be recycled multiple times through the rock cycle.