Bombs and Tubes
This photograph is of the opening into a lava tube, surrounded by lava rock bombs, as found while hiking the Lava Trail in Utah's Snow Canyon State Park.
When lava magma is deep underground, it is under very high pressure. As it moves toward the surface, it carries pieces of molten rock with it, and these are ejected out of vents. These molten blobs cool and solidify in the air and then fall back to earth. Hiking Snow Canyon’s Lava Trail, one will find many of these “lava bombs” on or nearby the hiking paths. And as the magma arrives at the earth’s surface, it breaks apart the cooled crust above it, creating jumbled masses of rock. Many of these rocks are brightly colored, reflecting the high iron oxice content on their surfaces.
Hiking Snow Canyon’s Lava Trail, one may also encounter deep, dark holes. Leading to caves. These are “lava tubes.” When lava flows, surface lava cools and hardens to a solid crust. When the volcanic eruption ends, the lava beneath these crusts drains out, leaving behind a hollow tube. These may remain hidden, but at times the thin surface crust breaks down and one finds a deep hole, surrounded by “lava bombs” of various sizes and colours.
(Notes from “Geology Underfoot in Southern Utah,” by Richard Orndorff, Robert Wider and David Futey.)
Bombs and Tubes
This photograph is of the opening into a lava tube, surrounded by lava rock bombs, as found while hiking the Lava Trail in Utah's Snow Canyon State Park.
When lava magma is deep underground, it is under very high pressure. As it moves toward the surface, it carries pieces of molten rock with it, and these are ejected out of vents. These molten blobs cool and solidify in the air and then fall back to earth. Hiking Snow Canyon’s Lava Trail, one will find many of these “lava bombs” on or nearby the hiking paths. And as the magma arrives at the earth’s surface, it breaks apart the cooled crust above it, creating jumbled masses of rock. Many of these rocks are brightly colored, reflecting the high iron oxice content on their surfaces.
Hiking Snow Canyon’s Lava Trail, one may also encounter deep, dark holes. Leading to caves. These are “lava tubes.” When lava flows, surface lava cools and hardens to a solid crust. When the volcanic eruption ends, the lava beneath these crusts drains out, leaving behind a hollow tube. These may remain hidden, but at times the thin surface crust breaks down and one finds a deep hole, surrounded by “lava bombs” of various sizes and colours.
(Notes from “Geology Underfoot in Southern Utah,” by Richard Orndorff, Robert Wider and David Futey.)