History lessons from a volcano

High lava fountain during early phase of the 1959 Kilauea eruption.

Volcanic eruptions are constantly changing the face of our planet, as well as other rocky planets scattered across the universe. Underneath the solid earth, hot magma, or liquid rock, stirs about, sometimes rising to the surface or blasting out of a volcano. The expelled lava then covers the ground and eventually cools to form new rocks and crystals -- a brand new solid surface on top of the old one.

Because this process happens continually over long periods of time, scientists and researchers can learn a lot about the history of the planet by studying the rocks beneath our feet. Now, researchers say they have found a tool to help them understand the history of lava flow and rock formation on our planet and on others: the element iron.

Researcher Fang-Zhen Teng and colleagues have identified unique properties of iron isotopes, or iron atoms with slightly different weights, contained in magma that allows them to chart a history of the magma's movement on the planet. Looking at samples of rock and crystals from the lava lake of Kilauea Iki in Hawaii, which formed during a volcanic eruption in 1959, Teng and his team observed that iron isotopes separate from each other between the time they melt and the time they form new crystals.

This property of iron isotopes to separate at high temperatures is not found in other metals that have been tested, like magnesium or lithium. So far, it seems to be unique to iron isotopes, which makes iron a potentially powerful tool for studying how mountains and canyons form over long periods of time.

In the future, this new application for iron could also help researchers understand the origins of our own planet, as well as how other planets in the universe came to be.

This study appears in the 20 June issue of the journal Science.

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