Why do fossils and dinosaur bones often preserve in sedimentary rocks instead of igneous rocks?

Fossils are best preserved when organisms are buried in sediments that later harden into rock. The low temperatures of sedimentary environments allow bones, shells, and impressions to survive long enough for mineralization to occur. Igneous rocks form from magma or lava, and the heat is generally too high for biological material to survive. Metamorphic rocks can also damage fossils because heat and pressure alter or destroy them. That is why the richest fossil record is found in sedimentary basins.