Which types of sedimentary rocks contain fossils?

Sedimentary rocks that contain fossils are primarily classified as organic sedimentary rocks. These rocks form from the accumulation of organic material, such as plant and animal remains. Over time, this organic material is buried and subjected to pressure and temperature, leading to the formation of rock types like limestone, which can contain fossils of marine organisms, or coal, which forms from the accumulation of plant material.

The presence of fossils in organic sedimentary rocks is significant because these fossils provide valuable information about the past environments and the organisms that lived in those environments. Fossils are not typically found in igneous and metamorphic rocks, as these rock types form from processes involving intense heat and pressure, which generally destroy organic material. Clastic sedimentary rocks, which form from the accumulation of rock fragments and minerals, may occasionally contain fossilized remains but are less likely to preserve them than organic rocks, which are specifically derived from biological materials.