Ejecta: Crater Spew
Alamo Impact Crater Formation

Accretionary lapilli

The impact force of a bolide into the underlying rock layers generates an immense amount of crater ejecta. Crater ejecta consist of rock fragments of varying sizes (less than a meter and as big as 20 meters in diameter!) that are thrown out of the impact crater and deposited elsewhere dependent upon their size and density. So many fragments are thrown into the air they create a wall of rock in all directions around the impact, known as an ejecta blanket. Crater ejecta can also consist of dust-size particles of rock that can cloud the air around the impact region. Accretionary lapilli are also formed within the crater ejecta and deposited throughout the impact region.

Read more about lapilli.