Friday, December 17, 2010
This is one of my favorite cave features here at Oregon Caves National Monument. It’s a quartz diorite dike encrusted with calcite.
Water (carrying minerals) flows through cracks in the marble bedrock. Quartz diorite is less permeable than marble, and when the water is unable to seep through. Instead, it flows down the surface of the dike, coating one side with calcite formations.
This is my favorite example of this, but there’s a much more prominent one along the tour route, so you should visit sometime!
If you’d like to learn more about the caves, you should read Ranger Gaelyn’s fantastic cave tour part one and part two!