And actually, most people don't pay attention to this fact but in reality only about 1/3 of phyla appear in the Cambrian fossil record. So not only is the explosion spanning tens of millions of years, but it also isn't even all encompassing. Most people aren't generally familiar with precambrian microshellies that have been discovered over the past couple decades. But eventually strobel will catch up with the research.
“Only some phyla appear in the Cambrian explosion. In particular, all plants postdate the Cambrian, and flowering plants, by far the dominant form of land life today, only appeared about 140 Mya (Brown 1999).
Even among animals, not all types appear in the Cambrian. Cnidarians, sponges, and probably other phyla appeared before the Cambrian. Molecular evidence shows that at least six animal phyla are Precambrian (Wang et al. 1999). Bryozoans appear first in the Ordovician. Many other soft-bodied phyla do not appear in the fossil record until much later. Although many new animal forms appeared during the Cambrian, not all did. According to one reference (Collins 1994), eleven of thirty-two metazoan phyla appear during the Cambrian, one appears Precambrian, eight after the Cambrian, and twelve have no fossil record.
And that just considers phyla. Almost none of the animal groups that people think of as groups, such as mammals, reptiles, birds, insects, and spiders, appeared in the Cambrian. The fish that appeared in the Cambrian was unlike any fish alive today.”
Morris, Henry M. 1985. Scientific Creationism. Green Forest, AR: Master Books, pp. 80-81.
Watchtower Bible and Tract Society. 1985. Life--How Did It Get Here? Brooklyn, NY, pp. 60-62.
Small shelly fauna - Wikipedia
And here is a table of phyla I've made myself, all are welcome to critique it.
View attachment 310021