Within the boundaries of the Mojave National Preserve, there is another landmark with “National Landmark” status, that being the Cinder Cones and Lava Flows National Natural Landmark. In 1973, the designation was made to protect Cima Dome, along with the Cima Volcanic Field and Cima Volcanic Range. In all it encompasses forty volcanic cinder cone vents, and extensive basaltic lava flows in a volcanic field covering fifty-eight square miles.
Volcanic activity began in this region 7.6 million years ago, and continued through about 8,000 – 10,000 ago. Their last eruption is believed to have taken place at the end of the most recent ice age. Thirty of the cinder cones and their lava flow are from the Pleistocene age (2,588,000 to 11,700 years ago), the remainder are from the Quaternary age (11.7 thousand years ago to today).
When most people think of a volcanic eruption, the idea of large explosions come to mind. This is not the case with cinder cones. Cinder cones form when the lava eruption is like a slow flowing fountain. For instance slowly squeezing a bottle of chocolate syrup, allowing the syrup to slowly run down the bottle.
This slow fountain like process created lava tubes, within the lava flow. As the lava spread out across the land, the top layer began to cool and form a hard layer. Meanwhile hot lava would continue to flow under the upper layer. Once the eruption completed, and lava stopped flowing out of the cinder cone, the remaining lava below the cooled surface would either cool in place, or empty out to create a hollow tube below the upper layer.
One of these lava tubes is easily accessible off of the Aiken Mine Road. A set of stairs was placed at the entrance to allow for easy access to the underground chamber. Inside, visitors are treated with the opportunity to experience the dark chambers, as well as an impressive light show from natural holes, which allow sunlight to penetrate the darkness.