Image Album: The Bizarre Lava Pillars of Iceland

Lava pillars on land

the skaelinger valley in iceland — (Image credit: Tracy Gregg)

A 2013 study has concluded that bizarre, hollow spires in Iceland are a unique type of volcanic formation that was previously only known to form in the deep ocean.

Fortuitous discovery

lava pillars, skaelinger valley, iceland — (Image credit: Tracy Gregg)

University at Buffalo geologist Tracy Gregg was hiking with her husband in the Skaelinger Valley in 1998 in Iceland when she noticed the knobby, hollow spires dotting the landscape.

Troll war?

lava pillars in Skaelinger Valley, Iceland — (Image credit: Tracy Gregg)

Though her guide and others told her the rocks were the detritus of warring trolls who had tossed them through the landscape, Gregg was unconvinced.

Ocean formation

The formations looked very similar to those she studied in her research: lava pillars that form at mid-ocean ridges.

Underwater shapes

At places where the continental plates are pulling apart under the ocean, columns of hot water seep through the pillowy lava on the ocean floor. That process cools the lava surrounding the water columns, forming hardened, hollow pillars when the lava ebbs. The Icelandic spires, with their hollow interiors, seemed to have been formed in a very similar process.

Second look

lava pillars in Iceland — (Image credit: Tracy Greg)

Unfortunately, Gregg didn't have a chance to take a second look at these pillars until 2010, when her graduate student Kenneth Christie received a grant to travel to Iceland to inspect the pillars more closely.

Hollow interiors

lava pillow — (Image credit: Tracy Gregg)

The team concluded that the pillars formed just as they would have in the ocean, with hollow interiors encircled by lava walls. The findings change geologists' understandings of the types of interactions that are possible when lava meets water.

Glassy texture

lava pillars texture — (Image credit: Tracy Gregg)

Some of the pillars have a glassy texture, characteristic of the interaction between lava and water. The lava cooled fast enough to drip, but not fast enough to form crystals.

Steam or pillow

mossy lava pillar in Iceland — (Image credit: Tracy Gregg)

Previously, geologists believed that when water and lava met on land, the water either drowned the lava, forming pillowy structures, or the lava heated the water in a flash to form steam, which then exploded.