>To form coal you need two basic conditions: wet tropics and a hole to bury organic matter in for a long period of time,” Boyce says. During the formation of Pangea, collisions between continents raised mountain ranges while downwarping adjacent crust, which created massive basins. These basins became ideal depositories for wet organic plant matter, which was buried, compressed and cooked over geologic time to form coal. Similar conditions likely also produced coal deposits during the Mesozoic Era, and the Paleocene and Eocene epochs, often in conjunction with mountain-building episodes such as the formation of the Rocky Mountains.
This article from 2016 goes into the details:
https://www.earthmagazine.org/article/lack-fungi-did-not-lea...
>To form coal you need two basic conditions: wet tropics and a hole to bury organic matter in for a long period of time,” Boyce says. During the formation of Pangea, collisions between continents raised mountain ranges while downwarping adjacent crust, which created massive basins. These basins became ideal depositories for wet organic plant matter, which was buried, compressed and cooked over geologic time to form coal. Similar conditions likely also produced coal deposits during the Mesozoic Era, and the Paleocene and Eocene epochs, often in conjunction with mountain-building episodes such as the formation of the Rocky Mountains.