There is also volcanic material deposited here that presumably came from the Yellowstone area.

Initially, the vast majority of volcanic material remained within the crust.

An estimated 50 million cubic meters of volcanic material had been released by 5 November.

It is covered by sedimentary rock and layers of volcanic material on its surface.

The surface of Venus is mostly covered by volcanic materials.

Tuffite should therefore contain more than half of volcanic material.

Some other, mostly older sources state that tuffite may contain 10-50% volcanic material.

The underlying rock is a mixture of sedimentary and volcanic material.

The island is entirely made up of volcanic material.

The event involved the movement of 100 million cubic meters of volcanic material.