How are sedimentary rocks formed?

Sedimentary rocks are formed through the process of lithification, which occurs when sediments—such as particles of minerals, organic material, or fragments of other rocks—are deposited and subsequently compacted and cemented together over time. The crucial aspect of this process is the influence of pressure on the accumulating layers of sediment. As more and more layers build up on top, the weight exerts pressure that helps in squeezing the particles together. Additionally, minerals in the water can act as a binder, further cementing the particles. This process leads to the formation of sedimentary rocks, which can include a variety of textures and compositions depending on the source of the sediments and the conditions of deposition.

The other processes listed in the question describe different methods of rock formation, such as igneous rocks forming from volcanic activity or crystal growth in magma, and metamorphic rocks arising from the alteration of existing rock under heat and pressure. These processes do not pertain to the formation of sedimentary rocks, which specifically rely on the accumulation and compaction of sedimentary materials.