volcanic pipe

Scientific  

1. A vertical conduit below a volcano through which magma has passed and that has become filled with solidified magma, volcanic breccia, and fragments of older rock.

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Example Sentences

A diamond, the locksmith reminds himself, is only a piece of carbon compressed in the bowels of the earth for eons and driven to the surface in a volcanic pipe.

From Literature

At Ruby Hill near Bingara they were found in a breccia filling a volcanic pipe.

From Project Gutenberg

But if Connel found the yellow ground while setting the charge, and took time to dig a little and be sure there was blue ground under it, he would certainly have known that he was standing on top of a volcanic pipe.

From Project Gutenberg

"A volcanic pipe," Hartson Brant said softly.

From Project Gutenberg

Evidently Guevara had put a ring of men around the volcanic pipe and planned to hold it by force of arms.

From Project Gutenberg