lava spine

This acts like a volcanic plug and composes the lava spines that currently form pinnacles on Cayley's rugged summit.

The Castle is a lava spine located west of Squamish in southwestern British Columbia, Canada.

An early sign of a coming eruption is the growth of a so-called Peléan or lava spine, a bulge in the volcano's summit preempting its total collapse.

The thick magma associated with Peléan eruptions can form lava domes and lava spines in the volcano's vent or on the volcano's summit.

Lava spines are upright cylindrical masses of lava caused by the upward squeezing of pasty lava inside a volcanic vent.

A lava spine is a vertically growing monolith of viscous lava that is slowly forced from a volcanic vent, such as those growing on a lava dome (Bates & Jackson, 1987).

Similar to the lava spines remaining on the ridges to the south and east of Old Snowy Mountain, the dense core became exposed after the Packwood Glacier removed the softer ash and broken flows around it.

In February 1983, the dome activity of Mount St. Helens culminated in a spine that reached a height of about 100 ft before collapsing after two weeks, but another lava spine called the Whaleback never collapsed.

Once the volcanic eruptions came to an end, the ongoing forces of glacial erosion stripped away the outer layers of volcanic ash deposits and lava flows, uncovering the rocky lava spines where magma had cooled and hardened within the conduits of the volcano.