Which type of rock is typically formed by the accumulation of sediment over time?

Sedimentary rock is formed through the accumulation and compaction of sediments over time. These sediments can originate from the weathering and erosion of pre-existing rocks, the remains of organisms, or the precipitation of minerals from solutions. The process involves several stages: deposition, where sediments settle out of transport mediums like water, wind, or ice; compaction, where the weight of overlying materials compresses the sediments; and cementation, where minerals precipitate from groundwater and bind the sediments together.

Sedimentary rocks are characterized by their layered appearance and often contain fossils, making them key indicators of past environmental conditions. They can also provide important resources, such as coal, oil, and natural gas, which are formed from organic material trapped within these rock layers. This rock type differs significantly from igneous and metamorphic rocks, which form through different processes involving cooling and crystallization of magma or alteration due to heat and pressure, respectively. The distinction is crucial in geological studies to understand the Earth's history and the processes that shape its surface.