They include volcanic features, soil, fauna, flora, air, water, and archeological and historical remains. The National Park Service strives to maintain the health and balance of all of the strands of this intricate web. The monument contains part of the Great Rift, a volcanic rift zone that extends south from the Pioneer Mountains for 60 miles. Eruptions occurred intermittently along the Great Rift from 15,000 until 2,100 years ago, and are likely to begin again within the next 1,000 years. There is very little soil on the recent lava flows of the monument.
Soil forms primarily from the accumulation of wind-blown particles in cracks in the lava.
Given sufficient time, these cracks fill in completely allowing soil to build up on the surface. Older flows and cones are covered with soil supporting a climax community of shrubs and grasses. Although much of the monument surface consists of barren lava flows, plant communities are surprisingly diverse. The varied lava types, micro habitats within lava flows, changes in elevation and topography, and riparian areas all contribute to habitat diversity. The monument's flora reflects the geologic setting.