Lava and Water Battled at Grand Canyon

To sort out all the lava flows, Crow and his colleagues used light detection and ranging (LIDAR) data that was originally collected for the Grand Canyon Monitoring and Research Center (GCMRC) in the spring of 2000.

The LIDAR survey data allowed the team to map out the lava flows in relation to sea level, making it easier to identify the tops and bottoms of the lava flows seen pasted on the walls of the canyons.

As for exactly how the lava dams worked, how far they backed up water and how violently they failed, that's all still largely a matter of conjecture.

"There are many possible scenarios and explanations for how the dams were formed or were destroyed, and it's likely that we'll never know them all," said Cassandra Fenton, a geochemist at GeoForschungsZentrum Potsdam in Potsdam, Germany.

Fenton has studied what may be some of the largest lava dams in the Grand Canyon and their outburst floods.

"It makes you wish you could have been standing on the rim of the Grand Canyon watching it all happen when those lavas were damming the river, or see when the river finally overtook the dams," she said.

Related Links:

Larry O'Hanlon's blog: Earth Impacts

The Grand Canyon Monitoring and Research Center

NOAA: About LIDAR Data

How Stuff Works: Grand Canyon Travel Guide