Why are Cambrian fossils generally more abundant than fossils from earlier Precambrian rocks?

Cambrian fossils are generally more abundant than those from earlier Precambrian rocks primarily due to the evolution of biomineralization, which allowed animals to develop hard parts like shells, skeletons, and teeth. These mineralized structures have a much greater potential for preservation in the fossil record than the soft tissues that characterize most Precambrian life.123

While Precambrian organisms existed, they were largely soft-bodied, making their preservation rare and dependent on exceptional conditions. The Cambrian explosion marked a significant transition where many animal phyla independently evolved the ability to secrete hard, mineralized skeletons. Because these hard parts are resistant to decay and scavengers, they are far more likely to be buried and fossilized than soft-bodied organisms. Additionally, the expansion of shallow marine environments during the Cambrian provided ideal settings for the accumulation and preservation of these diverse, shell-bearing faunas.14352