Rear-arc basalt lava outcrop
![Rear-arc basalt lava outcrop](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/img7292.jpg?itok=huISlwqB)
Detailed Description
A 3-4m (10-12 ft) high outcrop of basalt lava, part of a broader lava flow. These flows were erupted about 300,000 years ago following basalt dike intrusions in a rear-arc region of northern California. The eruptions of three of these flows are thought to have taken place within several hundred years of each other.
Sources/Usage
Public Domain.