Sedimentary rocks can contain fossils because, unlike most igneous and metamorphic rocks, they form at temperatures and pressures that do not destroy fossil remains. Dead orga … nisms can become sediments which may, under the right conditions, become sedimentary rock.edimentary rocks can contain fossils because, unlike most igneous and metamorphic rocks, they form at temperatures and pressures that do not destroy fossil remains. Dead orga … nisms can become sediments which may, under the right conditions, become sedimentary rock.